Re: Steel Balls vs. Chickens
RE: Steel Balls vs. ChickensNational Research Council in Canada has used chiekens in conjunction with their wind tunnel tests for airworthiness of aircraft designs for at least 25 years. Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (after sale) - Original Message - From: Gary McInturff To: 'k.macl...@aprel.com' ; mtay...@hach.com ; geor...@lexmark.com ; emc-p...@ieee.org Sent: Thursday, September 27, 2001 2:14 PM Subject: RE: Steel Balls vs. Chickens You can find similar data by going through commercial aircraft test procedures. I've seen the video from Boeing of chickens going through turbine blades, cockpit deflections etc. Don't have a contact for you but its not a super secret military idea - and it the turbine test makes tasty sliced chicken for sandwiches. Gary -Original Message- From: k.macl...@aprel.com [mailto:k.macl...@aprel.com] Sent: Thursday, September 27, 2001 7:30 AM To: mtay...@hach.com; geor...@lexmark.com; emc-p...@ieee.org Subject: RE: Steel Balls vs. Chickens Then, of course, there is the (apocryphal?) story of the Brits forgetting to defrost the chickens in their tests... just goes to say that those dreally etailed test procedures can come in handy... Kathy M. MacLean President, APREL Laboratories -EMC-RF Safety-Antenna Design/Test-SAR/MPE-SAR/Near-Field Tools-Acoustics-Wireless- 51 Spectrum Way, Nepean, Ontario K2R 1E6 (613) 820-2730 fax (613) 820-4161 cell (613) 791-3777 Web site: http://www.aprel.com - watch for our new web site coming soon! -Original Message- From: Michael Taylor [mailto:mtay...@hach.com] Sent: September 26, 2001 3:52 PM To: 'geor...@lexmark.com'; emc-p...@ieee.org Subject: RE: Steel Balls vs. Chickens A really trick cannon was used at China Lake-NWTC Edwards-AFB to test the impact resistance on All Weather Aircraft wind screens canopy's. Fresh Frozen chickens were defrosted the day before and shot out of a high pressure tube at the subject wind screens canopy's simulating bird impact in flight. At the end of the test you could not imagine the carnage unless you saw it. What a mess. Many times I wished I was able to photograph the scene - but no cameras allowed. Michael Taylor. -Original Message- From: geor...@lexmark.com [mailto:geor...@lexmark.com] Sent: Wednesday, September 26, 2001 12:51 PM To: emc-p...@ieee.org Subject: Steel Balls vs. Chickens In the late 1960's I was working on what became IBM's first copier. We made frequent use of NESA glass, a PPG product. This consisted of an ultra-thin gold layer deposited on glass sheets. We could perform photoconductor light-discharge experiments by coating the PC on the gold surface, and expose from the opposite side. I was told that the NESA glass concept was developed during WWII to defrost bomber windshields. These were typically made of plexi-glass, and would not thermally conduct sufficient heat from within the cockpit to defrost the exterior. The gold coating was placed on the outside of the windshield, and DC current passed across the surface to create enough heat to melt frost. The question of durability of the gold coating to birds striking the surface was established by firing dead chickens at test surfaces. I often kidded one of my mechanical engineering friends that he could and should design a top-of-the-line chicken cannon, with variable muzzle velocity, variable bores for using birds of different sizes, etc. As you know, jet airplane engines are still tested for their resiliency to birds both small (near airport ground level) and large (those ecountered at high altitudes) by similar methods. George Alspaugh --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: 134kHz transmitter in the U.K.
In Canada there is licenced operation on 137.1Khz and I understand FCC just released a small segment for use on 433Khz on an experimental basis. Ralph Cameron - Original Message - From: Jacob Schanker j.schan...@worldnet.att.net To: Sykes, Bob bob.sy...@marconi.com; emc-p...@ieee.org Sent: Wednesday, September 19, 2001 4:07 PM Subject: Re: 134kHz transmitter in the U.K. Bob: You should be aware that there is a UK amateur radio band at 135.7 - 137.8 kHz. Please keep that in mind both from an interference and from an immunity standpoint. You'll need to check the RA's website for technical limitations. Another resource is the RSGB's website at www.rsgb.org.uk. Regards, Jack Jacob Z. Schanker, P.E. 65 Crandon Way Rochester, NY 14618 Phone: 716 442 3909 Fax: 716 442 2182 j.schan...@ieee.org - Original Message - From: Sykes, Bob bob.sy...@marconi.com To: emc-p...@ieee.org Sent: Wednesday, September 19, 2001 10:49 AM Subject: 134kHz transmitter in the U.K. Greetings, We are looking at providing a short range RFID system to the U.K., and I am tasked with determining the regulatory requirements for this system. It incorporates a low power transmitter/receiver operating at 134kHz. I am familiar with the LVD and EMCD requirements, but unable to determine RTTE applicability, or whether U.K. National regulations apply. Any help would be most appreciated. adTHANKSvance, -Bob Sykes Marconi Commerce Systems --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: CE Mark
Chris: Thanks for your intelligent reply and a little needed humor too. In my days of paid employment CSA electrical safety was where it was at. Nowdays I think they need Compliance Engineers to be able to determine which standard applies. I guess there could be two approaches, generic immunity or the way it is now. Either way, it seems to present as many problems. By the way, I'll endorse your cheques with CE, but only from my basement. Regards, Ralph Cameron - Original Message - From: Chris Chileshe chris.chile...@ultronics.co.uk To: emc-p...@majordomo.ieee.org Sent: Thursday, September 13, 2001 12:37 PM Subject: RE: CE Mark Hi Ralph, The CE mark is not exclusive to EMC. Indeed, it refers to compliance with all directives relevant to the product, so a teddy bear will be CE marked if it meets the requirements of the toy directive and all relevant safety directives. Pressure vessels will have to meet the requirements of the pressure directive and so on, and if any product crosses boundaries, it has to meet all the applicable directives. However, the CE mark is a declaration of conformity and you can self certify. This means I can disappear into my garage for a few weeks and emerge with a CE marked product - and it would be perfectly legal - as long as the declaration is true i.e. I have done what needs to be done to prove compliance, and one way to do this would be to test to applicable harmonised standards. Validity of self certification may change in due course but at the moment, that is how it is. I like Chris Maxwell's spin on the meaning of CE, and it would be true if every firm made a distinction between the compliance engineer and the designer. In all the companies I have worked for - we do it all i.e. the designer designs to spec, takes the product through type approval tests, then through precompliance and then through full compliance. So the electronics designers are responsible for meeting all the applicable directives (EMC, electrical safety) and functional type approval and they do so by product proving and EMC testing the product themselves - to the applicable standard. They are also responsible for the technical documentation for the electrical aspects of the product. The mechanical engineers and hydraulics engineers do likewise and when it's all done, the fall guy (engineering director) puts his signature on the declaration of conformity. What this means is that if the declaration should subsequently be proven false, he is the one who goes to the gallows. Wait a minute! I used to think everyone worked that way, but I get the feeling I may be doing too much! That does it! I am off to see the payroll people soon after sending this e-mail and hopefully will emerge with a CE marked cheque - or CE marked letter of dismissal!! You can never be too sure with these accounts people. Regards y'all - Chris Chileshe -Original Message- From: Ralph Cameron [SMTP:ral...@igs.net] Sent: Thursday, September 13, 2001 4:57 PM To: Chris Chileshe; emc-p...@majordomo.ieee.org Subject: Re: CE Mark I think its fair to state that CE also equates to designed in level of immunity to electromagnetic interference, i.e. reduced sensitivity or susceptibility. In my view , a highly desireable because it prevents a lot of what's out there from coming in and conversely a lot of what's inside from coming out. It's a compromise but better than nothing. Ralph cameron EMC Consulting and Suppression of Consumer Electronics (after sale) snip _ This message has been checked for all known viruses by Star Internet delivered through the MessageLabs Virus Scanning Service. For further information visit http://www.star.net.uk/stats.asp or alternatively call Star Internet for details on the Virus Scanning Service. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord
Re: CE Mark
I think its fair to state that CE also equates to designed in level of immunity to electromagnetic interference, i.e. reduced sensitivity or susceptibility. In my view , a highly desireable because it prevents a lot of what's out there from coming in and conversely a lot of what's inside from coming out. It's a compromise but better than nothing. Ralph cameron EMC Consulting and Suppression of Consumer Electronics (after sale) - Original Message - From: Chris Chileshe chris.chile...@ultronics.co.uk To: emc-p...@majordomo.ieee.org Sent: Thursday, September 13, 2001 7:52 AM Subject: RE: CE Mark This understanding (appended e-mail below) is correct AFAIK. I also checked out the website http://www.conformance.co.uk and they seem to agree with the notion it doesn't really mean anything *any more*. Here is an excerpt from their site .. . We quite often get asked what the 'CE' in the CE logo stands for. If anything it probably stands for Communitee Europeen being the French way of saying European Community. It could also represent Conformite Europeen. However, it is far from certain that whoever invented the mark (some bureaucrat in Brussels) had anything particular in mind other than to create a logo which would be universally recognised in the European Union, and given all the national prejudices about language in the different countries of the EU, even if the original inventor had something specific in mind, it was probably conveniently forgotten by the time it became 'official'. So, officially, it's just a logo and has no linguistic meaning. .. Best regards - Chris -Original Message- From: wmccaffe...@npeurope.com [SMTP:wmccaffe...@npeurope.com] Sent: Tuesday, September 11, 2001 2:44 PM To: Jody Leber Cc: 'emc-p...@majordomo.ieee.org' Subject: Re: CE Mark Hi Jody According to sources within the European Commission the letters CE now have no meaning. Communitie European seems to have been assumed from the inception of the directives but now CE means CE. Slaint _ This message has been checked for all known viruses by Star Internet delivered through the MessageLabs Virus Scanning Service. For further information visit http://www.star.net.uk/stats.asp or alternatively call Star Internet for details on the Virus Scanning Service. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: CE Mark
The correct French spelling for the English equivalent of community is communaute with an accent on the last e, according to my French dictionary. Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (after sale) - Original Message - From: geor...@lexmark.com To: Jody Leber jle...@ustech-lab.com Cc: emc-p...@majordomo.ieee.org Sent: Tuesday, September 11, 2001 8:23 AM Subject: Re: CE Mark Jody, I seem to recall that CE is for European Community but in Frech, i.e. Communite European. You can try looking around the EU website: http://europa.eu.int/comm/enterprise/newapproach/legislation/guide/legislati on.htm George Jody Leber jleber%ustech-lab@interlock.lexmark.com on 09/11/2001 07:30:53 AM Please respond to Jody Leber jleber%ustech-lab@interlock.lexmark.com To: 'emc-p...@majordomo.ieee.org' emc-pstc%majordomo.ieee@interlock.lexmark.com cc:(bcc: George Alspaugh/Lex/Lexmark) Subject: CE Mark Is there an offcial website that defines what the CE actually stands for? I believe it is Conformite Europeene, however I have seen other definitions. I seached the europa site but did not have any luck. Best Regards, Jody Leber Laboratory Manager jle...@ustech-lab.com http://www.ustech-lab.com U. S. Technologies 3505 Francis Circle Alpharetta, GA 30004 770.740.0717 Fax: 770.740.1508 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: UL vs CSA (IT product)
George: I don't think what I said differs substantially from what you said other than I intended to say that where electrical safety of consumer products is concerned only CSA and c-UL certification is acceptable in Canada. If you use a consumer product in Canada not so approved to CSA or c-UL, you'll have a problem with insurance. . In fact Ontario Hydro(now Hydro One) have authority to prevent you from using the product. Its amazing how many products enter the country without any certification because this is not examined at entry. Ralph Cameron - Original Message - From: geor...@lexmark.com To: emc-p...@ieee.org Sent: Monday, September 10, 2001 11:21 AM Subject: UL vs CSA (IT product) Amund, I believe some additional clarification is warranted. UL and CSA are private agencies and do not determine what is acceptable to market goods (ITE) in their respective countries. This is determined by government bodies. The U.S. OSHA has approved multiple Nationally Recognized Testing Laboratories to (NRTLs) to perform testing to the UL standards for ITE. These include UL and CSA. See: http://www.osha-slc.gov/dts/otpca/nrtl/index.html The Standards Council of Canada has approved multiple Certification Bodies to perform testing to the CSA standards for ITE. These include UL and CSA. See http://www.scc.ca/certific/colist_e.html Neither UL nor CSA is obliged to recognize or accept testing performed by the other agency, although their respective governments do so. Canada requires either CSA, c-UL, or marks of the other listed certification bodies. U.S. requires UL, CSA/NRTL, or marks of the other listed NRTLs. So, you can use either agency to get a mark acceptable in both countries. However, here is the down side of each: CSA/NRTL--Not as well known in the U.S. by large corporate customers. Requires some selling to convince that it is equal to UL. c-UL--OK for both country consumer/business markets, but Canadian government tends to give precidence to CSA marked ITE when bidding for its own use. George Alspaugh Lexmark International Inc. Ralph Cameron ralphc%igs@interlock.lexmark.com on 09/10/2001 09:33:00 AM Please respond to Ralph Cameron ralphc%igs@interlock.lexmark.com To: Horst Haug innova.ps%t-online...@interlock.lexmark.com, Peter Merguerian pmerguerian%itl.co...@interlock.lexmark.com, amund%westin@interlock.lexmark.com, emc-pstc%majordomo.ieee@interlock.lexmark.com cc:(bcc: George Alspaugh/Lex/Lexmark) Subject: Re: UL vs CSA (IT product) CSA accepts approval by ULC. The C is indicative of Canadian UL. UL is normally not accpetable by itself in Canada Ralph Cameron EMC Consulting and Suppresion of Consumer Electronics (after sale) - Original Message - From: Horst Haug innova...@t-online.de To: Peter Merguerian pmerguer...@itl.co.il; am...@westin.org; emc-p...@majordomo.ieee.org Sent: Monday, September 10, 2001 5:24 AM Subject: AW: UL vs CSA (IT product) Amund, UL accept components approved by CSA and CSA accepts components approved by UL. A CSA approved Power Supply within an end product with UL approval is no problem any more (that is my experience). The UL PAG practical application guide about is 1.5.002. I send it to you in a separate EMAIL. With best regards Horst Haug -Ursprüngliche Nachricht- Von: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]Im Auftrag von Peter Merguerian Gesendet: Montag, 10. September 2001 09:44 An: 'am...@westin.org'; emc-p...@majordomo.ieee.org Betreff: RE: UL vs CSA (IT product) Amend, See my answers in body of your message. UL and/or CSA certification are mandatory within the electrical safety area,to have access to the US and Canadian marked. Right ? I know there are some differences between them, the certification fee, the certification-handling period and the number of audit/year. My questions are: 1.Do they have the same status? Peter: Yes, to a certain extent. You must check the scope of their acceditations in OSHA's and Standard Council of Canada's websites. 2.What requirements do the end users/ buyers have, do most of them prefer one of the approvals? Peter: Depends on the categories. But most end-users are not aware that other NRTLs are capable of giving the same Listing service. You must educate them. 3.Do we have to go for both of them? Peter: One is enough, but as I said above, you must educate end-users to accept and also check if the test house is accredited for the particular standards. Best regards Amund Westin, Oslo/Norway --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your
Re: UL vs CSA (IT product)
CSA accepts approval by ULC. The C is indicative of Canadian UL. UL is normally not accpetable by itself in Canada Ralph Cameron EMC Consulting and Suppresion of Consumer Electronics (after sale) - Original Message - From: Horst Haug innova...@t-online.de To: Peter Merguerian pmerguer...@itl.co.il; am...@westin.org; emc-p...@majordomo.ieee.org Sent: Monday, September 10, 2001 5:24 AM Subject: AW: UL vs CSA (IT product) Amund, UL accept components approved by CSA and CSA accepts components approved by UL. A CSA approved Power Supply within an end product with UL approval is no problem any more (that is my experience). The UL PAG practical application guide about is 1.5.002. I send it to you in a separate EMAIL. With best regards Horst Haug -Ursprüngliche Nachricht- Von: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]Im Auftrag von Peter Merguerian Gesendet: Montag, 10. September 2001 09:44 An: 'am...@westin.org'; emc-p...@majordomo.ieee.org Betreff: RE: UL vs CSA (IT product) Amend, See my answers in body of your message. UL and/or CSA certification are mandatory within the electrical safety area, to have access to the US and Canadian marked. Right ? I know there are some differences between them, the certification fee, the certification-handling period and the number of audit/year. My questions are: 1.Do they have the same status? Peter: Yes, to a certain extent. You must check the scope of their acceditations in OSHA's and Standard Council of Canada's websites. 2.What requirements do the end users/ buyers have, do most of them prefer one of the approvals? Peter: Depends on the categories. But most end-users are not aware that other NRTLs are capable of giving the same Listing service. You must educate them. 3.Do we have to go for both of them? Peter: One is enough, but as I said above, you must educate end-users to accept and also check if the test house is accredited for the particular standards. Best regards Amund Westin, Oslo/Norway -- Get your firstname@lastname email for FREE at http://Nameplanet.com/?su --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael
Re: Susceptibility level of medical devices (incubator) - urgent!
Antonio: I would say many incubators were manufactured when there were no concerns and the susceptibility was a function of the design and very variable. I have heard they vary from 0.1V/m to 10V/m but don't think there is any set standard. The medical gurus prefer to isolate their equipment by physical barriers and hope that something will not affect them In Canada Health Canada could answer thequestion . In the U.S. I believe its the Food and Drug Administration. Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (After sale). - Original Message - From: Antonio Sarolic antonio.saro...@fer.hr To: emc-p...@majordomo.ieee.org Sent: Monday, August 27, 2001 11:59 AM Subject: Susceptibility level of medical devices (incubator) - urgent! Hi I need urgent info on susceptibility level of medical electronic devices, especially baby incubators. Can anyone confirm if it is 1V/m (according to EU standards)? The EMI source is the GSM BS antenna (900MHz). Thanks very much. Antonio Antonio Sarolic, M.S.E.E. Faculty of Electrical Engineering and Computing Dept. of Radiocommunications and Microwave Engineering Unska 3, HR-1 Zagreb, CROATIA tel. +385 1 61 29 789, fax. +385 1 61 29 717 E-mail: antonio.saro...@fer.hr --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: board scanning on the cheap (sort of)
I think this was known as Kirlian photogrphy - spelling may be wrong. It can detect the electrostatic charge surrounding living tissue. Ralph Cameron - Original Message - From: geor...@lexmark.com To: emc-p...@ieee.org Sent: Thursday, August 09, 2001 4:00 PM Subject: board scanning on the cheap (sort of) Well, this discussion has reached the point where I must add something I read about some years ago. It goes something like this: For many years, Russia was known to conduct many experiments involving paranormal activity, probably to determine if there were any military value in such phenomena as psychic communications etc., if in fact they existed. I was surprised to see an article in a National Geographic years ago that told of one such experiment. It involved photography of the aura (presumably electromagnetic fields) that surround the human body. The peaks in this aura, or field were found to be consistent with the primary acupuncture points long before identified by the Chinese. A faith (hand-on) healing was photographed, revealing that the aura of the healer diminished during the process while the aura of the person being healed increased, i.e. a possible transfer of energy. The point of all this is if the Russians truly developed a means to photograph the low power EMF surrounding humans, it would seem that the same technique would also photograph the EMF surrounding PCBs etc. I have no comment on whether any of the above is true science, but I DID read it in the generally respected National Geographic, albeit not a scientific journal. George Alspaugh --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: ESD - time between successive discharges
John: I thought I had lost your original statement about CE not having a bearing on Quality. I would agree also. The statement was made, as I recall, in some article in Compliance Engineering. Not that UL is a quality mark or RU or FCC 15 etc. Quality is highly dependant on how your marketing people perceive it and refers to appearance, dependability, reputation, need fulfillment and a host of things thought to benefit the cutomer - from the manufacturer's view. On the other hand a CE mark is a rating of performance and how many consumers even know about it? I ask every computer salesman I have occasion to meet the meaning of CE and I have yet to find one who knows. After I explain it to him, he agrees that some generic immunity is a good thing. If you look at all the components and larger computer peripherls now bearing a CE mark, it must be cost effective to include it. I suppress consumer equipment that suffers from no immunity with a simple non intrusive method and suggest to the same consumer to be aware and next time look for a product with the CE mark. I yet to encounter a problem with a CE marked product ( modems, video cards, displays, CD players, and even boom boxes) that could never hack it in today's RF environment. CE is a consumer benefit because it guarnatees a minimum level of immunity With all these domestic wireless devices , it makes prudent engineering sense. Designed in is the only way to go. I don't want to do this forever. Ralph Cameron EMC Consulting and Suppression of Consumer Electronics. (after sale) - Original Message - From: John Woodgate j...@jmwa.demon.co.uk To: emc-p...@majordomo.ieee.org Sent: Tuesday, August 07, 2001 4:34 PM Subject: Re: ESD - time between successive discharges 95fbd8b0830ed511b7720002a51363f1319...@exw-ks.ks.lsil.com, Ehler, Kyle keh...@lsil.com inimitably wrote: No John, I'm not referring to you. (or anyone else in particular) I dont know you well enough -yet..lol I'm just spaking on how we do the job of ensuring that our products meet the standards. I only pick up typos when they are amusing (like, 'We then repeated the tests for completemess.'), or could create confusion. We take this work very seriously and I agree with you that the CE mark is not a quality mark, Good; my comment was directed to those who might think it is. I agree with most of the rest of your comments. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk This message and its contents are not confidential, privileged or protected by law. Access is only authorised by the intended recipient - this means YOU! The contents may be disclosed to, or used by, anyone and stored or copied in any medium. If you are not the intended recipient, please advise the sender yesterday at the latest. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: TV nostalgia
As I recall, the old pcb material was made from urea and smelled like it. Or the exploding selenium rectifiers were a dead giveaway, just like H2S. - Original Message - From: oover...@lexmark.com To: emc-p...@majordomo.ieee.org Sent: Friday, August 03, 2001 5:55 PM Subject: RE: TV nostalgia I have noticed several responses related to the smell of the old equipment. I had been thinking the very same thing. You could trouble-shoot by the type of smell a failed component produced (cap vs. resistor, vs choke, etc.) Ever notice how connected one's memory and smells are connected? Think about the number of things, both good and bad, that particular smells recall. Fresh cut grass, a certain type of perfume, a new or old car, fresh paint, burning leaves, foods, etc. rbusche%es@interlock.lexmark.com on 08/03/2001 05:02:21 PM Please respond to rbusche%es@interlock.lexmark.com To: emc-pstc%majordomo.ieee@interlock.lexmark.com cc:(bcc: Oscar Overton/Lex/Lexmark) Subject: RE: TV nostalgia How about the reported X-Ray emissions from the old high voltage regulators and the 25-35KV anode voltages? Those old color sets were beasts. It is interesting to note that the process of keeping the CRT filaments warm, (instant on) was the cause of numerous TV fires. But you know, there's something pleasant (or nostalgic) about the smell of a tube type radio or TV. Perhaps it's just my age. Rick Busche -Original Message- From: Ehler, Kyle [mailto:keh...@lsil.com] Sent: Friday, August 03, 2001 2:38 PM To: 'Ralph Cameron'; 'EMC and Safety list' Subject: RE: TV nostalgia Which reminds me of other oddball video contraptions. A few years back I had to dispose of a Heathkit GR-2000 25 TV w/onscreen digital clock option. Alas, it worked great, but the digital matrix tuner did not like CATV (ch. 2-13 only). Its entire chassis was copper plated steel. All pcb's were 94V0 and, typical of Heath products, documented more than thoroughly. Very well made! kyle -Original Message- From: Ralph Cameron [mailto:ral...@igs.net] Sent: Friday, August 03, 2001 2:41 PM To: Ehler, Kyle; 'Rich Nute'; 'EMC and Safety list' Subject: Re: TV nostalgia And lest we forget the Hallicrafters electrostatic deflection systems. You could sure get a poke off those. Ralph Cameron - Original Message - From: Ehler, Kyle mailto:keh...@lsil.com To: 'Rich Nute' mailto:ri...@sdd.hp.com ; 'EMC and Safety list' mailto:emc-p...@majordomo.ieee.org Sent: Friday, August 03, 2001 9:23 AM Subject: RE: TV nostalgia My experience was with the Packard-Bell transistorized models. I think the aversion I have was prejudiced by the fellow who mentored me. I had little reason to doubt, but then the sets I worked on, had a callback history that may have been created by my mentor. -kyle -Original Message- From: Rich Nute [ mailto:ri...@sdd.hp.com mailto:ri...@sdd.hp.com ] Sent: Thursday, August 02, 2001 5:36 PM To: emc-p...@majordomo.ieee.org mailto:emc-p...@majordomo.ieee.org Subject: TV nostalgia Okay... more nostalgia and a bit on safety back in those days... so that we don't stray too far from the subject matter of this forum. My first TV was a Motorola 7-inch round in a Bakelite cabinet. The speaker was the same size as the CRT. My second was the famous RCA 10-inch round chassis with 32 tubes. I could pull out 15 tubes and still have a usable picture. Kyle mentions Packard Bell, which I considered a straight-forward, good product. It used the Standard Coil turret tuner. The one that won my respect was Muntz TV. It was CHEAP! When you looked inside the chassis, there was nothing there compared to the other TVs. They really knew how to take the cost out of the TV! Amazingly enough, its picture was among the best, and its reliability was indeed the best -- no parts to go bad! The company was owned by Mad Man Muntz, the classic Los Angeles used car dealer. In the mid-fifties, GE came out with a transformerless 17-inch TV. One side of the power line was tied to the chassis (2-wire plug back in those days). The only protection was the plastic knob on the shafts of the various controls. When servicing this TV, you quickly learned never to touch the chassis! The power supply was a simple full-wave rectified power line. The tube heaters were connected in a series-parallel arrangement. These sets were the initiation of UL's investigation into antenna coupling capacitors. These capacitors provided the isolation between the TV antenna terminals and the mains voltage. TV sets of those days consumed between 400 and 600 watts. When they were turned on, the cold filaments were a very low impedance, so the turn-on current was very high. The off-on switch
Re: TV nostalgia
RE: TV nostalgiaAnd lest we forget the Hallicrafters electrostatic deflection systems. You could sure get a poke off those. Ralph Cameron - Original Message - From: Ehler, Kyle To: 'Rich Nute' ; 'EMC and Safety list' Sent: Friday, August 03, 2001 9:23 AM Subject: RE: TV nostalgia My experience was with the Packard-Bell transistorized models. I think the aversion I have was prejudiced by the fellow who mentored me. I had little reason to doubt, but then the sets I worked on, had a callback history that may have been created by my mentor. -kyle -Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Thursday, August 02, 2001 5:36 PM To: emc-p...@majordomo.ieee.org Subject: TV nostalgia Okay... more nostalgia and a bit on safety back in those days... so that we don't stray too far from the subject matter of this forum. My first TV was a Motorola 7-inch round in a Bakelite cabinet. The speaker was the same size as the CRT. My second was the famous RCA 10-inch round chassis with 32 tubes. I could pull out 15 tubes and still have a usable picture. Kyle mentions Packard Bell, which I considered a straight-forward, good product. It used the Standard Coil turret tuner. The one that won my respect was Muntz TV. It was CHEAP! When you looked inside the chassis, there was nothing there compared to the other TVs. They really knew how to take the cost out of the TV! Amazingly enough, its picture was among the best, and its reliability was indeed the best -- no parts to go bad! The company was owned by Mad Man Muntz, the classic Los Angeles used car dealer. In the mid-fifties, GE came out with a transformerless 17-inch TV. One side of the power line was tied to the chassis (2-wire plug back in those days). The only protection was the plastic knob on the shafts of the various controls. When servicing this TV, you quickly learned never to touch the chassis! The power supply was a simple full-wave rectified power line. The tube heaters were connected in a series-parallel arrangement. These sets were the initiation of UL's investigation into antenna coupling capacitors. These capacitors provided the isolation between the TV antenna terminals and the mains voltage. TV sets of those days consumed between 400 and 600 watts. When they were turned on, the cold filaments were a very low impedance, so the turn-on current was very high. The off-on switch was often mounted on the back of the volume control. Eventually, the contact resistance of the switch would grow to the point where the I**2*R power would melt the solder and the power wires would come loose. It was common to have a customer report that his TV was dead, and it was due to the lack of a good connection to the switch. At one company, we had metal bat-handle toggles blow out of the switch due to the cold filament load. Out of this experience, UL developed the requirements for the TV-rated switch, which had specially-designed contacts that would not overheat when used in a TV or similar application. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: EM-Field Head Protection
Too bad they don't give the resonant frequency of such a device. It could have interesting applications for university lectures. ( in the near field ). Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (After sale) - Original Message - From: Price, Ed ed.pr...@cubic.com To: emc-p...@ieee.org Sent: Wednesday, July 18, 2001 10:22 AM Subject: EM-Field Head Protection Finally, there's a site with construction details and usage suggestions, for aluminum foil EM-field head protectors. Design, metallurgy and history of the subject are also covered. http://zapatopi.net/afdb.html Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: Test Equipment ...
Bob, thanks for that information. I guess the second question would be is the device required to bear a part 15 complaince label? This iinformation is very helpful because most of the answers I get from the authorities indicate Canada's Digital Emission standard ( identical to FCC Part15) is for digital products or those containing mnicroprocessors. Thanks Ralph Cameron - Original Message - From: r...@etlsemko.com To: ral...@igs.net; taniagr...@msn.com; dmck...@corp.auspex.com; emc-p...@majordomo.ieee.org Sent: Wednesday, August 01, 2001 2:43 PM Subject: RE: Test Equipment ... Part 15 does NOT address only digital devices. It does make a lot of reference to digital devices, presumably because these are the worst offenders. However, it defines incidental radiator as a product that generates RF energy while it operates, but is not designed to intentionally generate RF (e.g. clocks). Examples Part 15 gives include dc motors and mechanical light switches. Part 2.802 defines a radiofrequency device as ANY device which is capable of emitting RF energy including The incidental, unintentional and intentional radiators defined in part 15. Part 15 addresses incidental radiators with its 'motherhood and apple pie' statement (15.5(b)) - it must not cause interference and must accept it. It also says (15.13) that manufacturers shall employ good engineering practices to minimize the risk of harmful interference. 15.101 covers Class A and B external switching power supplies and says that they are subject to verification. For many incidental radiators it may not make sense to do the testing because the RF generated is very low. However, it may be wise to test some items like lamp dimmers. The bottom line is that Ralph's observation, re: noisy analog devices. is supported by the FCC. Regardless of being digital or analog, a product is required to be verified to the limits/intent of Part 15. Bob Martin, P.E., N.C.E. Intertek Testing Services NA, Inc. ETL SEMKO 70 Codman Hill Road Boxborough, MA 01719 Tel (978) 263-2662 Fax (978)263-7086 www.etlsemko.com rmar...@etlsemko.com mailto:rmar...@etlsemko.com -Original Message- From: Ralph Cameron [mailto:ral...@igs.net] Sent: Wednesday, August 01, 2001 10:01 AM To: Tania Grant; Doug McKean; EMC-PSTC Discussion Group Subject: Re: Test Equipment ... Many analog devices such as smps emit (conduct) terrible noise in the radio spectrum yet they are exempt. How come? I can cite the supplies for low level halogen/xenon lighting , exercise treadmills and some computer displays. A switch is a switch is a switch and anything that breaks current is capable of generating harmful interference- analog is no exception. The higher the current - the worse the spectral effluent. Where's the rationale there? Ralph Cameron EMC Consulting and Suppression of Consumer Elelctronics ( After sale) - Original Message - From: Tania Grant mailto:taniagr...@msn.com To: Doug McKean mailto:dmck...@corp.auspex.com ; EMC-PSTC Discussion Group mailto:emc-p...@majordomo.ieee.org Sent: Wednesday, August 01, 2001 12:15 AM Subject: Re: Test Equipment ... Doug, et al, FCC Part 15 addresses digital devices only. And they continue to use the term digital over and over again. The scope of FCC Part 15 does not address analog devices, whether they be industrial, commercial, or medical test equipment. However, the FCC are exempting (and some say temporarily) digital devices that are used exclusively as industrial, commercial, or medical test equipment. Therefore, no, a company that makes analog test equipment does not have to EMC test such products. (And someone tell me please how exactly they would test them if they wanted to!) taniagr...@msn.com mailto:taniagr...@msn.com - Original Message - From: Doug McKean Sent: Tuesday, July 31, 2001 5:46 PM To: EMC-PSTC Discussion Group Subject: Re: Test Equipment ... Price, Ed wrote: Doug: The rationale that I recall is that test equipment is expected to be used by people who understand the nature of electrical measurements and safety. These people will have the knowledge and resources, beyond those of a typical consumer, to recognize and ameliorate interference and other problems. Further, it is argued that compliance measures might hinder absolute accuracy and sensitivity of measurement equipment. Also, that test equipment is not usually manufactured in numbers comparable to typical consumer equipment, so the impact on a society is less. IIRC, there is a somewhat shorter and simpler explanation buried somewhere in Part 15. Okay, follow me on this for just a minute. 47 CFR, 15.103, Exempted devices. (c) A digital device used exclusively as industrial, commercial, or medical test equipment. The important word is digital. Why just digital? Does this mean if a company makes analog industrial
Re: Test Equipment ...
Many analog devices such as smps emit (conduct) terrible noise in the radio spectrum yet they are exempt. How come? I can cite the supplies for low level halogen/xenon lighting , exercise treadmills and some computer displays. A switch is a switch is a switch and anything that breaks current is capable of generating harmful interference- analog is no exception. The higher the current - the worse the spectral effluent. Where's the rationale there? Ralph Cameron EMC Consulting and Suppression of Consumer Elelctronics ( After sale) - Original Message - From: Tania Grant To: Doug McKean ; EMC-PSTC Discussion Group Sent: Wednesday, August 01, 2001 12:15 AM Subject: Re: Test Equipment ... Doug, et al, FCC Part 15 addresses digital devices only. And they continue to use the term digital over and over again. The scope of FCC Part 15 does not address analog devices, whether they be industrial, commercial, or medical test equipment. However, the FCC are exempting (and some say temporarily) digital devices that are used exclusively as industrial, commercial, or medical test equipment. Therefore, no, a company that makes analog test equipment does not have to EMC test such products. (And someone tell me please how exactly they would test them if they wanted to!) taniagr...@msn.com - Original Message - From: Doug McKean Sent: Tuesday, July 31, 2001 5:46 PM To: EMC-PSTC Discussion Group Subject: Re: Test Equipment ... Price, Ed wrote: Doug: The rationale that I recall is that test equipment is expected to be used by people who understand the nature of electrical measurements and safety. These people will have the knowledge and resources, beyond those of a typical consumer, to recognize and ameliorate interference and other problems. Further, it is argued that compliance measures might hinder absolute accuracy and sensitivity of measurement equipment. Also, that test equipment is not usually manufactured in numbers comparable to typical consumer equipment, so the impact on a society is less. IIRC, there is a somewhat shorter and simpler explanation buried somewhere in Part 15. Okay, follow me on this for just a minute. 47 CFR, 15.103, Exempted devices. (c) A digital device used exclusively as industrial, commercial, or medical test equipment. The important word is digital. Why just digital? Does this mean if a company makes analog industrial, commercial, or medical test equipment, that equipment MUST be tested? Regards, Doug McKean (slowly becoming more confused ...) --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: Examples of EMC problems in the real world
When the material of the core and the windings are as specified , the emission reduction is uniform over the range for which it is designed- 1Mhz-30Mhz. Resonance is avoided by a distributed winding Ralph Cameron - Original Message - From: Wan Juang Foo f...@np.edu.sg To: Ralph Cameron ral...@igs.net Cc: emc-p...@majordomo.ieee.org Sent: Thursday, June 28, 2001 1:45 AM Subject: Re: Examples of EMC problems in the real world The so call reduction in emmission does not happen all the time. There is still the possibility of resonance, this I have observed in several cases over the past 7 years . Tim Foo, E-mail: f...@np.edu.sg ECE, School of Engineering, http://www.np.edu.sg/ece/ Tel: + 65 460 6143 Ngee Ann Polytechnic, Fax: + 65 467 1730 535 Clementi Road, Singapore 599489 Ralph Cameron ral...@igs.net To: rehel...@mmm.com Sent by: cc: emc-p...@majordomo.ieee.org, (bcc: Wan Juang owner-emc-pstc@majordomFoo/ece/staff/npnet) o.ieee.org Subject: Re: Examples of EMC problems in the real world 06/27/01 09:16 PM Please respond to Ralph Cameron Bob: It just occurred to me that list members may not be failimiar with the application of these components after manufacture. If needed I would be glad to elaborate. Basically, since conducted immunity also decreases conducted emissions its a double benefit. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: Examples of EMC problems in the real world
Bob: It just occurred to me that list members may not be failimiar with the application of these components after manufacture. If needed I would be glad to elaborate. Basically, since conducted immunity also decreases conducted emissions its a double benefit. regards Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (After sale) - Original Message - From: rehel...@mmm.com To: Ralph Cameron ral...@igs.net Cc: emc-p...@majordomo.ieee.org Sent: Wednesday, June 27, 2001 6:51 AM Subject: Re: Examples of EMC problems in the real world Ralph, what is a toroidal cord? Is it a power cord with toroids? Bob Heller 3M Product Safety, 76-1-01 St. Paul, MN 55107-1208 Tel: 651- 778-6336 Fax: 651-778-6252 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: Examples of EMC problems in the real world
Bob, I wish it were then I wouldn't have to wind it. No my eyesight is getting poor and I mean toroidal ( ring / donut shaped ) core. of powdered iron material. Ralph - Original Message - From: rehel...@mmm.com To: Ralph Cameron ral...@igs.net Cc: emc-p...@majordomo.ieee.org Sent: Wednesday, June 27, 2001 6:51 AM Subject: Re: Examples of EMC problems in the real world Ralph, what is a toroidal cord? Is it a power cord with toroids? Bob Heller 3M Product Safety, 76-1-01 St. Paul, MN 55107-1208 Tel: 651- 778-6336 Fax: 651-778-6252 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Bluetooth-IEEE802.11 interference potential
The website that contains one opinion on this problem has surfaced at www.wireless-nets.com/whitepaper_interference.htm Other links from there are quite productive. Ralph Cameron EMC Consulting and Suppression of Consumer Elecrtonics (After sale)
Re: Radio controlled cars (toys)
In Canada both the 27Mhz and 72-75Mhz bands are available for radio controlled models. There are power restritions and the frequency assignements may be viewed on p.14 of the pdf file at http://strategis.ic.gc.ca/pics/sf/ric18.pdf Ralph Cameron - Original Message - From: Lothar Schmidt To: 'EMC-PSTC (E-mail)' Sent: Wednesday, June 20, 2001 3:29 PM Subject: Radio controlled cars (toys) Hi all Thanks a lot for the inputs I got. It is great to have a group like this you can just ask questions and you get a lot of answers. Thanks again. Lothar Hi Group, is there any special frequency range assigned to radio remote control toys? Are there different classes like professional devices to control e.g. planes or helicopters? My customer is looking for a frequency range above 300 MHz. Best Regards Lothar Schmidt Technical Manager EMC/Bluetooth, BQB, Competent Body Cetecom Inc. 411 Dixon Landing Road Milpitas, CA 95035 Phone: +1 (408) 586 6214 Fax: +1 (408) 586 6299
Re: FCC + FCC = FCC? - Outlaw
Doug: I think you hit the crux of the matter with one correction, if I may. Hams in the U.S. are operating as amateurs but have a legal obligation to the country in times of need . In Canada , we operate ( myself included) with permission and have no legal obligations to the government. Our equipment could be comandeered but not the operator. This is a disticntion between our two countries. I advise any consumer in a known high ambient RF area ( such as near broadcast /commercial /ham transmitters to look for the CE mark. 9 times out of 10 the additional components have not been omitted to seel to North America. Likewise in Canada, Industry Canada no longer investigates consumer EMC complaints ( i.e. lack thereof) as of two years ago. Ralph Cameron EMC Consulting and Suppression of Consumer Electronic Equipment ( after sale) - Original Message - From: Doug McKean dmck...@gte.net To: emc-p...@majordomo.ieee.org Sent: Thursday, June 21, 2001 2:32 AM Subject: RE: FCC + FCC = FCC? - Outlaw Sorry but I respectfully disagree ... If the FCC were to say yes to anyone being an outlaw for building their own PC and not having it tested, then why does the FCC label essentially tell everyone suffering from interefernce to take care of it themselves? The FCC was created to protect the big alphabet communication companies from themselves. Me building my own PC is peanuts compared to some of the issues these guys deal with. And cable tv is starting to make the issue of interfering with commercial broadcast a moot point. Heck, I don't even see the pixels blink at all anymore even with the microwave being used only 10 feet away. I was told, not sure how true it is, that the FCC in the early years of Part 15 took to task a famous computer company selling computers which hooked up to your tv screen. They were famous for intereference. I know, I had one. So the FCC threatened to confiscate the units from said company. Well, the sales were going down and the company said, sure big brother, to ahead ... So the FCC took them. Lots of them. In fact, so many, they had to store them all in an area which closed down part of the FCC facility. The company went on to declare it all as a loss. The FCC got stuck with the inventory. I don't think they want to repeat that again. And thus the reason for the wording of the label. Unless you're a real threat to commercial communications (such as a ham) they really don't want to be bothered. Just my 3.1415 cents worth ... - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: FCC + FCC = FCC?
I think this raises a parallel issue of testing methodology versus practical application. Many devices/ boards/ add ons are tested with minimal connecting attachments i.e. conductors, other than those to power the devie and those required to make the measurement. When separate devices such as those mentioned are placed into actual service , the systems themselves become attached to conductors with sizeable electrical lengths. Here we have a computer with internal modem , external speakers, keyboard and display- all have connecting cables external to the deices which have been tested but now the environment contributes external signals which weren't present when these devices were tested indicidually. Without reducing CE or taking steps to improve conducted immunity it seems logical that emissions will be radiated by the connecting attachments and the devices become more susceptible to external interfering sources such as high ambient RF signals. Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (After sale) - Original Message - From: Doug McKean dmck...@corp.auspex.com To: EMC-PSTC Discussion Group emc-p...@ieee.org Sent: Wednesday, June 20, 2001 8:32 PM Subject: Re: FCC + FCC = FCC? Building your own machine doesn't constitute you being a PC mfr. I think that's the reading here. - Doug - Original Message - From: Steve Grobe ste...@transition.com To: 'IEEE Forum' emc-p...@majordomo.ieee.org Sent: Wednesday, June 20, 2001 2:03 PM Subject: RE: FCC + FCC = FCC? If you are so am I. As are a few dozen people I know. The only way to get an OS other than Windows to run well is to build your own machine. Steve -Original Message- From: Massey, Doug C. [mailto:masse...@ems-t.com] Sent: Wednesday, June 20, 2001 2:42 PM To: 'IEEE Forum' Subject: RE: FCC + FCC = FCC? Just to further confuscate the issue - I once built my own home PC. I bought a box, motherboard, CPU, memory, variety of ISA cards, etc. It worked so well, I built a couple or three more for family and friends, and sold them to those family and friends at a good price. I didn't check radiated emissions. Am I an FCC Outlaw ? Doug Massey LXE, Inc. snip --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: Radio controlled cars (toys)
I believe the I.S.M. bands in Canada but will verify that tomorrow- Ralph Cameron - Original Message - From: Pettit, Ghery To: 'Bailey, Jeff' ; EMC-PSTC (E-mail) Sent: Wednesday, June 20, 2001 1:40 PM Subject: RE: Radio controlled cars (toys) Just remember that the frequencies between 50 and 54 MHz require an amateur radio license in order to use them. They are not for unlicensed use. Ghery Pettit Intel -Original Message- From: Bailey, Jeff [mailto:jbai...@mysst.com] Sent: Wednesday, June 20, 2001 10:18 AM To: EMC-PSTC (E-mail) Subject: RE: Radio controlled cars (toys) Lothar: There are also several channels allocated in the 75 MHz, 50 MHz and 27MHz region. Jeff Jeff Bailey Compliance Engineering SST - A Division of Woodhead Canada Phone: (519) 725 5136 ext. 363 Fax: (519) 725 1515 Email: mailto:jbai...@mysst.com Web: www.sstech.on.ca -Original Message- From: Price, Ed [mailto:ed.pr...@cubic.com] Sent: Wednesday, June 20, 2001 10:19 AM To: 'Lothar Schmidt'; EMC-PSTC (E-mail) Subject: RE: Radio controlled cars (toys) Lothar: There are several channels allocated in the 72 MHz region for the USA. I'm not current on this area, but I believe there are some channels specifically for model aircraft control (possibly only by the modelers' private convention). Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis -Original Message- From: Lothar Schmidt [mailto:lothar.schm...@cetecomusa.com] Sent: Tuesday, June 19, 2001 4:59 PM To: EMC-PSTC (E-mail) Subject: Radio controlled cars (toys) Hi Group, is there any special frequency range assigned to radio remote control toys? Are there different classes like professional devices to control e.g. planes or helicopters? My customer is looking for a frequency range above 300 MHz. Best Regards Lothar Schmidt Technical Manager EMC/Bluetooth, BQB, Competent Body Cetecom Inc. 411 Dixon Landing Road Milpitas, CA 95035 Phone: +1 (408) 586 6214 Fax: +1 (408) 586 6299
Re: Wireless Network Issues
Kyle: Take a look at www.Intellon.com . They detail a link to some of the problems associated with proximity of Bluetooth devices to 802.11 LAN specs. These are claimed to be potential interference problems related to hop frequency differences in the two spread spectrum systems. There is also concern with the power line conducted control systems and the Continental Automated Building Associated attempted to address some of the issues related to compatibility during their conference held at the end of May. There are some 26 different standards all independantly developed which I'm sure is enough for a statistical study of the problem. There have been several papers on lack of EMC in hospitals - some originating from McGill University in Montreal. The main problem there seems to be lack of any emc equipment requirements ( although changing due to liability ) and the solution has been to isolate the areas containing the radio sensitive equipment. Tha Radio Advisory Board of Canada's EMC sub committee did address some concerns toward cable TV radiation and possible effects on some aircraft frequencies. With those problems largely overcome by regulating the cable operators , another issue has arisen and that could affect radio aids to navigation and it may have to do with radiation from home wiring above 2Mhz .. This is conceivable with ever increasing data rates and unshielded wiring. When I was chairman of the RABC EMC committee for a couple of years, there were many instances of life threatening incidences related to lack of EMC. Ralph Cameron Electromagnetic Compatibiliy Consulting and Suppression of Consumer Electronics ( after sale) - Original Message - From: kyle_cr...@dell.com To: emc-p...@majordomo.ieee.org Sent: Monday, June 11, 2001 5:23 PM Subject: Wireless Network Issues Hi All, I am currently researching wireless intereference issues for a project and I was wondering if anyone could answer a few of my questions. First off, any links to information that deals directly with wireless interference on airplanes or in hospitals would be appreciated. Secondly, I am curious how similar cell phone wireless technology is to wireless network technology(Wi-FI), from an EMI standpoint. The reason I ask is that I can find a lot of information about cell phone intereference, but I have found nothing about wireless network interference. I am still learning a lot about this, so any information that you could provide would be appreciated. Thanks, Kyle --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: Ethernet baluns
Paolo: I wonder if you could suffer a little line loss and match the balun with a resistive minimum loss pad and use 50 ohm connecotrs?. That way you could minimiz reflections and possiby improve EMC? My two sents worth. Ralph Cameron EMC Culting and Suppression of Consumer Electronics (After Sale)- - Original Message - From: Paolo Roncone paolo...@tin.it To: emc-p...@majordomo.ieee.org Sent: Wednesday, May 30, 2001 11:53 AM Subject: Ethernet baluns Hi everyone: I'm looking for a passive (no ac/dc power supply needed) balun to convert from an Ethernet 10b2 (unbalanced coax 50 ohm) to an Ethernet 10bT (balanced, twisted pair, UTP, 100 ohm). Anyone knows if this kind of box exists ? So far I came up with a perfect match, but for the impedance of the coax connector (75 ohms instead of 50 ohms). We need this in order to improve the EMC behavior of the 10b2 Ethernet that we have to live with (you bet it's a real damn pain in the neck EMC-wise !!!). Thanks Paolo --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: 120V appliance on 240V supply
I would think the clock timing and microprocessor timing would suffer and as a result it may deliver heat but programming prarameters could be drastically incorrect. For short periods of time the heating effects would be minimal but who knows what a safe time period would be. Better to have deisgned the trasnformers for 50Hz to begin with . Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (After sale) - Original Message - From: Ravinder Ajmani ajm...@us.ibm.com To: emc-p...@ieee.org Sent: Monday, May 14, 2001 11:48 AM Subject: 120V appliance on 240V supply Hi, I am interested in knowing if a 120V, 60Hz microwave oven can be safely used on a 240V, 50Hz mains supply with a step-down transformer. Regards, Ravinder Email: ajm...@us.ibm.com *** Always do right. This will gratify some people and astonish the rest. Mark Twain --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: 2. 4 GHz cordless telephone, question of general interest
In terms of heating ( cooking ) 900Mhz is more efficient but its a question then of density of tissue , I understand that between 70-90Mhz the human body absorbs most energy and that first microwave ovens were designed around 450Mhz but 2.4 Ghz was an I.S.M. band so permitted limitless power. The leakage in the average Microwave oven should be so small that you'd never hear it on a 2.4Ghz cell phone (i.e. 50Mhz off frequency) many offie type 2.4Ghz cordless phone use 900mw on the base unit and 200mw on the handset. I would suspect the field intensity that close to the head could be substantial. Ralph Cameron - Original Message - From: Ken Javor ken.ja...@emccompliance.com To: emc-p...@ieee.org Sent: Friday, April 20, 2001 5:40 PM Subject: 2. 4 GHz cordless telephone, question of general interest Someone on this forum likely knows the answer to this question... I was at Wal-Mart the other day and they had 2.4 GHz cordless phones on clearance. My home cordless phones are 900 MHz. One is multiple channels, the other is some kind of spread spectrum. 2.4 GHz is very close to 2450 MHz, the microwave oven frequency that resonates with H2O molecules. Is 2.4 GHz close enough to 2450 MHz to cause significantly more heating than 900 MHz (in the human head adjacent to the head/handset antenna)? I realize this is very low power relative to a cell phone, but I wonder if the issue was ever addressed. Another way of asking this question is, what is the Q of H20 resonance? If it is much better than 50, the problem is not important. If it is 50 or less, then 2.4 GHz would transfer more energy to head tissue than 900 MHz. One way of measuring this effect would be to time how long it takes to raise the temperature of a beaker of water a set amount at 2450 MHz, and then time how long it takes at 2400 MHz... But this all must have been done already... --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: RSS139 and RSS210
RSS stands for Radio Standards Specification and RSS210 covers Unlicensed Low power transmitting devices ( All Bands) . I can send you the PDF file if you wish. The Industry Canada web site has most of these specs and RSS 139 is one I'm not familiar with but I will obtain the title for you. Try their website at www.strategis.ic.gc.ca/s10372e.html#miscellaneousDocuments Regards Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (After Sale) - Original Message - From: Peter Merguerian pmerguer...@itl.co.il To: EMC-PSTC (E-mail) emc-p...@majordomo.ieee.org Sent: Thursday, April 19, 2001 6:52 AM Subject: RSS139 and RSS210 Dear All, Can anyone identify what RSS139 and RSS210 standards stand for? It looks like Canadian requirements for receiving and transmitting equipment. If so, what are the equivalent FCC or other standards? Thank you. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: 972-3-5339022 Fax: 972-3-5339019 Mobile: 972-54-838175 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: Ferrites experience ....... last comment
To the Ferrite discussion: I've refrained from responding to the ferrite question because of being away but I would confirm what Amand states. I use powdered iron FT240-43 from Fair-Rite as they make them for Amidon and have the properties desired to reduce common mode signals appearing on connecting cables to consumer devices- VCR, TV sets, Hi-Fi speaker cables etc. I have treated over 300 cases of RF getting into telephones ( via the phone cable connection) , VCRs via the sheath on the TV cable , modems, speaker cables etc. Success in siolating the offending RF ( 500Khz- over 30Mhz ) has been in ecess of 90%. I say if it works, don't know kit,. 20 years ago I had an EMC engineer characterise the attenutaion over the above frequency range and Mix 43, with init. perm of 850 was the best compromise. As Amand states Mix 77 would work better below 500Khz. The minimum attenutaion was 15dB and approached 27dB at 35Mhz . At 30 dB it provided rejection of RF common mode signals of 25dB. It is important that between 8-9 tuuns be used and spaced over the surface of the toroid to flatten the attenuation curve. Many telephone filters made by ATT and others I have found to have a very peaked response over the HF range and will work sometimes and sometimes not. The nice thing about external devices like this are they don't degrade performance in any way, are re-useable, quite economical and easy to install. It is also important to keep the toroids as close as possible to the device being protected in order to minimize pickup due to re radiation. This is a simple procedure which many manaufacturers overlook , yet could save them a bundle in returned product and in some cases litigation. The components can be used to suppress incoming RF our outgoing.from the product. I started out doing this type of suppression free of charge but after using several hundred toroids ( the 2.4 O.D. ones for power line cables) I started to recover my costs. These thinbgs really do work. Ralph Cameron EMC Consutling and Suppression of Consumer Electronics ( After sale) - Original Message - From: am...@westin.org To: emc-p...@majordomo.ieee.org Sent: Wednesday, March 14, 2001 5:22 PM Subject: Re: Ferrites experience ... last comment Hi all, Many thanks to all of you who participated in this ferrite discusson. I have leard a lot about ferrites the last 10 days. In my special case, I would like to give you some information: We had a problem with conducted emisson on the DC supply line to a telecom product. The harmonic switching frequency was 160kHz and our problems was in the range 160kHz-5MHz. We used a toroid (DC cable five turns in the Toroid)and we managed to decrease the noise about 10-15dB in the frequency range 1-5MHz. The toroid had an outer/inner diameter of 61mm/36mm (a big one). We used a toroid with material 43 and its permeability is approximate 850. Material 43 has its application areas from 30-200MHz, so we should have had a toroid with an other material. I think a toroid with a material 77 (permeability 2000) could have helped us with the 160kHz-1MHz band. Next time . One last comment, try to avoid snap-on ferrites. Remember the air gap, you will have a large increase in the impedance even if you use strips to tighten it together. Use the solid ones See you later. Best regards Amund Westin, Oslo/Norway On 6 Mar 2001 19:16:37 - am...@westin.org wrote: Hi all, During conducted emission test, we have 150kHz power supply switching distrubance on the 48VDC-line, and we can not insert capacitors,chokes or any filters on the line. Do you have any experience using ferrites to suppress noise in the band 100kHz - 5MHz ? We have used ferrites with success on I/O-lines during radiated emission, but no experience on DC-lines (use LISN). Best regards Amund Westin, Oslo / Norway -- Get your firstname@lastname email for FREE at http://Nameplanet.com/?su --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, -- Get your firstname@lastname email for FREE at http://Nameplanet.com/?su --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list
Re: Battery terminals isolation
John: How about an insulated wrench? Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (After sale) - Original Message - From: John Woodgate j...@jmwa.demon.co.uk To: emc-p...@majordomo.ieee.org Sent: Wednesday, February 28, 2001 3:47 PM Subject: Re: Battery terminals isolation sa9d1398.077@sao0002n, SERGIO LUIZ DA ROCHA LOURES SERGIO sergioro...@siemens.com.br inimitably wrote: Can the group tell me if there is any requirement about isolations of lead acid battery terminals? We have a 48V equipment powered by lead acid batteries. The negative of the batteries set is connected to the enclosure. When the batteries need to be replaced, short circuit happens if the tool used to detach the connectors touch the enclosure and the positive of the batteries. Information to disconnect the negative terminal first before replace the batteries is clear in the service manual, but I don't know if only this is sufficient. I don't know of anything explicit in any standard, but the consequences of shorting a 48 V battery could be very serious, up to loss-of-life. Therefore I would think in terms of the General Safety Directive, which says, in effect, 'make it safe, then make it safer'. So: - put a warning notice **next to the battery** saying 'Disconnect THIS terminal first.' Don't rely on a drunken blind, idiot knowing which is the negative one. - if possible, fix to the negative connector a plastic shield that covers up the positive terminal and connector, so you can't even get at the positive terminal without first removing the negative one. If you need to be able to measure the battery voltage with a multimeter, put a small hole in the shield that will just admit a test-prod. You could perhaps put the warning notice on the shield itself. -- Regards, John Woodgate, OOO - Own Opinions Only. Phone +44 (0)1268 747839 Fax +44 (0)1268 777124. http://www.jmwa.demon.co.uk Foxhunters suffer from tallyhosis. PLEASE do not mail copies of newsgroup posts to me. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: Copper Thieving
Doug: A picture says a 1000 words. Well Done. Ralph Cameron - Original Message - From: POWELL, DOUG doug.pow...@aei.com To: rehel...@mmm.com; emc-p...@majordomo.ieee.org Sent: Monday, January 22, 2001 11:40 AM Subject: RE: Copper Thieving I would like to add a little more to this discussion. Last August we had a serious problem occur when a board house arbitrarily added thieving dots to one of our PCBs. This significantly reduced the spacing requirement in a safe-unsafe area. As it turned out, we did not catch the problem immediately because the hipot test did not uncover the problem. Eventually the PCB board house started using a different stamping ink on their inspection stamp that had organic content and it failed hipot. They were using stamp pad ink from the local office supply and could not immediately identify its content. As it turned out the basic board design had enough spacing (barely) because it was originally designed with 230V (L-N) systems in mind and is only used on 120V (L-N) products. We still insisted that they remove the dots from the Gerber files. In the process I learned that there are several things to watch for. 1) Thieving dots and thieving bars are used primarily for balancing copper during etch and plating and for balancing the wave during assembly. These dots may be added at the time Gerber files are generated or even edited into the Gerber files by the PCB house and never show up on a CAD system. 2) Venting of PCBs, I am not entirely clear on this but I understand that this is a modification to the ground plane and other copper fills, to allow process gases to escape from between the laminates on inner layers. Watch for changes in ground currents and reduced maximum current capability. This also has the Gerber files editing problems. 3) Inspection stamps should be epoxy based only, also adhesive labels often applied by companies to identify PCB's should not be printed with LaserJet toner! Toner is very conductive and should not be allowed to bridge safe/unsafe areas. Attached is a photo of a PCB with the thieving dots and triangular inspection stamp that failed hipot. If you look closely at the stamp you can see the trench created by the hipot test. -doug = Douglas E. Powell Regulatory Compliance Engineer Advanced Energy Industries, Inc. 1625 Sharp Point Dr. Ft. Collins, Co 80525 mailto:doug.pow...@aei.com www.advanced-energy.com = -Original Message- From: rehel...@mmm.com [mailto:rehel...@mmm.com] Sent: Thursday, January 18, 2001 7:15 AM To: emc-p...@majordomo.ieee.org Subject: Copper Thieving Please excuse my lack of knowledge..what is copper thieving? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Consumer Electronics Compatibility
Sorry, the attachment called EMCAB-1, Elecrtomagnetic Compatibility Bulletin -1 is 230K of PDF format so it exceeds the server limit. If any one is interested i will send it to you separately. Ralph Cameron - Original Message - From: Price, Ed ed.pr...@cubic.com To: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org Sent: Tuesday, January 16, 2001 10:02 AM Subject: Consumer Electronics Compatibility Ralph: Would you provide a little more detail about the 30MHz Consumer Electronics compatibility problems that you have been addressing? Are you finding that the path is a direct galvanic connection, or is the problem caused primarily by radiation of energy off of the power lines? What are the most common emitting devices, and what types of devices are the most numerous victims? And of course, what's usually the best solution? Thanks, Ed -Original Message- From: Ralph Cameron [mailto:ral...@igs.net] Sent: Monday, January 15, 2001 7:57 PM To: Ken Javor; dan kwok Cc: EMC-PCST (E-mail) Subject: Re: Site Correlation No, your message is clear, what I am saying is that the emissions below 30Mhz cause the majority of the interference problems to consumer electronics and that's not being addressed. Ralph Cameron - Original Message - From: Ken Javor ken.ja...@emccompliance.com To: Ralph Cameron ral...@igs.net; dan kwok dk...@intetron.com Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org Sent: Monday, January 15, 2001 10:34 PM Subject: Re: Site Correlation I must have been unclear in my previous message. The purpose of controlling cable cm CE is to control the resultant cable-induced RE, which are controlled to protect tunable antenna-connected radio receivers, period. There was never any other purpose for controlling CE or RE. Ken Javor Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Site Correlation
What it boils down to Chris is the lack of immunity of the consumer equipment contributes to degradation of the intended function. Once the undesired energy reaches the consumer device there's no way to get rid of it. The rememdy is to prevent it from reaching the device and or isolating it from the source. At one time injection clamps were used for immunity testing- are they still? Ralph Cameron - Original Message - From: Chris Maxwell chris.maxw...@gnnettest.com To: 'Ralph Cameron' ral...@igs.net; Ken Javor ken.ja...@emccompliance.com; dan kwok dk...@intetron.com Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org Sent: Tuesday, January 16, 2001 8:38 AM Subject: RE: Site Correlation Seems like this thread has gotten into how to correlate common mode cable currents with their expected radiated emissions. For those interested, Fischer Custom Communications makes coupling and measuring clamps which can measure common mode surface currents on cables and surfaces. They used to publish some application notes regarding the usage of their clamps to measure surface/cable currents and how to correlate them to expected radiated emissions. I read them a couple of years ago. I never bought the clamps, but it did make for some very good technical reading. I do know of a table top power supply manufacturer that uses this method almost exclusively. They send one power supply to a calibrated OATS. They get it to pass. Then, when the sample comes back to the factory, they take clamp measurements of the common mode currents of the AC input and DC output cable. They then model the power supply as a dipole antenna with the AC input cable and DC output cable being the two poles. For future power supplies, they then use the clamp method in-house to measure the cable currents, if the currents pass, they assume the supply passes radiated emissions. This won't work for every product, but it does fit this application well. The power supply company could make more than 10 versions (3.3VDC, 5VDC, 9VDC, 12VDC ...) of a power supply with the same case and cabling so it can save them a great deal of time and money. The supplies only have two cables, which is easy to model. The supplies have clock speeds in the 100-500Khz range, meaning that most of thier harmonics will be dead over 230Mhz, which is the cutoff for most coupling clamps. I thought that this method would be difficult to use for our products since we have higher clock speeds and multiple cables. I guess many times the measurement method is somewhat defined by what you're measuring. Chris Maxwell Design Engineer GN Nettest 6 Rhoads Drive, Building 4 Utica,NY 13502 email: chris.maxw...@gnnettest.com phone: 315-266-5128 fax: 315-797-8024 -Original Message- From: Ralph Cameron [SMTP:ral...@igs.net] Sent: Monday, January 15, 2001 10:57 PM To: Ken Javor; dan kwok Cc: EMC-PCST (E-mail) Subject: Re: Site Correlation No, your message is clear, what I am saying is that the emissions below 30Mhz cause the majority of the interference problems to consumer electronics and that's not being addressed. Ralph Cameron - Original Message - From: Ken Javor ken.ja...@emccompliance.com To: Ralph Cameron ral...@igs.net; dan kwok dk...@intetron.com Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org Sent: Monday, January 15, 2001 10:34 PM Subject: Re: Site Correlation I must have been unclear in my previous message. The purpose of controlling cable cm CE is to control the resultant cable-induced RE, which are controlled to protect tunable antenna-connected radio receivers, period. There was never any other purpose for controlling CE or RE. Ken Javor -- From: Ralph Cameron ral...@igs.net To: Ken Javor ken.ja...@emccompliance.com, Dan Kwok dk...@intetron.com Cc: EMC-PCST \(E-mail\) emc-p...@majordomo.ieee.org Subject: Re: Site Correlation Date: Mon, Jan 15, 2001, 8:51 PM Perhaps what you state is correct Ken but there has been a supposition that RE , induced or other wise when converted to conducted current does not effect other devices connected to those same conductors whether they be power, incoming TV or telephone cables etc. All these conductors intercept RE and their effects have been eliminated in 90% of cases( I have personally suppressed ) , by suppresseing the common mode signals.Over 300 successes is a significant statistic. Ralph Cameron . - Original Message - From: Ken Javor ken.ja...@emccompliance.com To: Dan Kwok dk...@intetron.com; Ralph Cameron ral...@igs.net Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org Sent: Monday, January 15, 2001 5:42 PM Subject: Re: Site Correlation Mr. Kwok's theories are logical and no doubt bear on the subject, but there is a historical angle that bears
Re: Site Correlation
No, your message is clear, what I am saying is that the emissions below 30Mhz cause the majority of the interference problems to consumer electronics and that's not being addressed. Ralph Cameron - Original Message - From: Ken Javor ken.ja...@emccompliance.com To: Ralph Cameron ral...@igs.net; dan kwok dk...@intetron.com Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org Sent: Monday, January 15, 2001 10:34 PM Subject: Re: Site Correlation I must have been unclear in my previous message. The purpose of controlling cable cm CE is to control the resultant cable-induced RE, which are controlled to protect tunable antenna-connected radio receivers, period. There was never any other purpose for controlling CE or RE. Ken Javor -- From: Ralph Cameron ral...@igs.net To: Ken Javor ken.ja...@emccompliance.com, Dan Kwok dk...@intetron.com Cc: EMC-PCST \(E-mail\) emc-p...@majordomo.ieee.org Subject: Re: Site Correlation Date: Mon, Jan 15, 2001, 8:51 PM Perhaps what you state is correct Ken but there has been a supposition that RE , induced or other wise when converted to conducted current does not effect other devices connected to those same conductors whether they be power, incoming TV or telephone cables etc. All these conductors intercept RE and their effects have been eliminated in 90% of cases( I have personally suppressed ) , by suppresseing the common mode signals.Over 300 successes is a significant statistic. Ralph Cameron . - Original Message - From: Ken Javor ken.ja...@emccompliance.com To: Dan Kwok dk...@intetron.com; Ralph Cameron ral...@igs.net Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org Sent: Monday, January 15, 2001 5:42 PM Subject: Re: Site Correlation Mr. Kwok's theories are logical and no doubt bear on the subject, but there is a historical angle that bears inspection. About the time FCC limits for IT equipment were being drawn up (late '70s) PCs were not yet on everyone's desktop. Most of the business equipment that would have been envisioned to be qualified to USC Title 47, Part 15, Subpart J would have been stand-alone items such a copier, with the only cable connection being ac power. The report which documents the development of the CE and RE limits/test methods found in the above mentioned FCC limits specifically states that 30 MHz was picked as the cutoff between CE and RE for the reason of radiation efficiency per Mr. Kwok's surmise, but also because 30 MHz was the lowest frequency at which a 3 m OATS measurement would provide the desired accuracy. Ken Javor P.S. Said report also demonstrated that the CE limit below 30 MHz sufficed to control RE from the power cable to levels sufficient to protect against cable radiation-induced rfi. -- From: Dan Kwok dk...@intetron.com To: Ralph Cameron ral...@igs.net Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org Subject: Re: Site Correlation Date: Mon, Jan 15, 2001, 2:49 PM Hello Ralph: That's a good question. At one time, I pondered the same question myself. There are obviously plenty of communication systems operating under 30 MHz. I suppose there are reasons why CISPR or CISPR 22 does not specify radiated emissions below 30 MHz. I can suggest one possibility. Perhaps others here will come up with more. For a fixed cable of length L, the ratio of L/lambda gets progressively small for frequencies much less than 30 MHz with most commercial EUTs. If we consider the cable part of dipole antenna, the reduction in frequency has a diminishing effect on the antenna's radiation resistance. Given a constant current, the radiated power would decrease with decreasing radiation resistance. At 550 KHz (bottom of the AM broadcast band in North America), the 1/4 wavelength is 136 meters. Even if the antenna's reactance is ignored, one would need very long cables driven by a significant CM noise voltage at this frequency to radiate much energy. -- Daniel Kwok Principal EMC Engineer Intetron Consulting, Inc. Vancouver, Canada Phone (604) 432-9874 Email dk...@intetron.com Web http://www.intetron.com; Ralph Cameron wrote: Ken: I like the idea of setting a limit to common mode currents on attaching cables but mI wonder why CISPR has chosen to start such measurements at 30Mhz when most of the common mode currents are the result of switching products and are generated harmonically from the fundamental and as such propagate from the low Khz range up through 30Mhz. is there no consideration for those who occupy the spectrum below 30Mhz? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list
Re: Site Correlation
Perhaps what you state is correct Ken but there has been a supposition that RE , induced or other wise when converted to conducted current does not effect other devices connected to those same conductors whether they be power, incoming TV or telephone cables etc. All these conductors intercept RE and their effects have been eliminated in 90% of cases( I have personally suppressed ) , by suppresseing the common mode signals.Over 300 successes is a significant statistic. Ralph Cameron . - Original Message - From: Ken Javor ken.ja...@emccompliance.com To: Dan Kwok dk...@intetron.com; Ralph Cameron ral...@igs.net Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org Sent: Monday, January 15, 2001 5:42 PM Subject: Re: Site Correlation Mr. Kwok's theories are logical and no doubt bear on the subject, but there is a historical angle that bears inspection. About the time FCC limits for IT equipment were being drawn up (late '70s) PCs were not yet on everyone's desktop. Most of the business equipment that would have been envisioned to be qualified to USC Title 47, Part 15, Subpart J would have been stand-alone items such a copier, with the only cable connection being ac power. The report which documents the development of the CE and RE limits/test methods found in the above mentioned FCC limits specifically states that 30 MHz was picked as the cutoff between CE and RE for the reason of radiation efficiency per Mr. Kwok's surmise, but also because 30 MHz was the lowest frequency at which a 3 m OATS measurement would provide the desired accuracy. Ken Javor P.S. Said report also demonstrated that the CE limit below 30 MHz sufficed to control RE from the power cable to levels sufficient to protect against cable radiation-induced rfi. -- From: Dan Kwok dk...@intetron.com To: Ralph Cameron ral...@igs.net Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org Subject: Re: Site Correlation Date: Mon, Jan 15, 2001, 2:49 PM Hello Ralph: That's a good question. At one time, I pondered the same question myself. There are obviously plenty of communication systems operating under 30 MHz. I suppose there are reasons why CISPR or CISPR 22 does not specify radiated emissions below 30 MHz. I can suggest one possibility. Perhaps others here will come up with more. For a fixed cable of length L, the ratio of L/lambda gets progressively small for frequencies much less than 30 MHz with most commercial EUTs. If we consider the cable part of dipole antenna, the reduction in frequency has a diminishing effect on the antenna's radiation resistance. Given a constant current, the radiated power would decrease with decreasing radiation resistance. At 550 KHz (bottom of the AM broadcast band in North America), the 1/4 wavelength is 136 meters. Even if the antenna's reactance is ignored, one would need very long cables driven by a significant CM noise voltage at this frequency to radiate much energy. -- Daniel Kwok Principal EMC Engineer Intetron Consulting, Inc. Vancouver, Canada Phone (604) 432-9874 Email dk...@intetron.com Web http://www.intetron.com; Ralph Cameron wrote: Ken: I like the idea of setting a limit to common mode currents on attaching cables but mI wonder why CISPR has chosen to start such measurements at 30Mhz when most of the common mode currents are the result of switching products and are generated harmonically from the fundamental and as such propagate from the low Khz range up through 30Mhz. is there no consideration for those who occupy the spectrum below 30Mhz? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org
Re: Site Correlation
Hello Dan: Your explanation makes a lot of sense, as applied to RE. It appears that conducted emissions or CE have been largely ignored' nevertheless, cause many problems when the radiating source is external to the device. The average home is a great unintentionl antenna and when conducted currents from noisey switching power supplies or RF from local transmitting facilities, etc appear on house wiring it causes two problems: It radiates ( or re readiates, as the case may be) and disupts or causes radiosensitive equipment to malfuntion or as they say, respond in an unintended manner. This issue has not been addressed very well, except equipment bearing the CE mark does have some conducted immunity , so it is a feature that has a benefit in spite of how some have defined the CE mark. My reason for asking about the frequency range of the RE measurements was to determine the background behind the restriction in the frequency range. It also related to the incidence of equipment malfucntion being almost entirely due to common mode conducted currents. Of course, once RE are intercepted by house wiring they become conducted and that's when the problem begins. You answerd the original question , thanks. Ralph Cameron EMC Consulting and Suppression of Consumer Elecrtonic Equipment ( After sale) p.s. After sale means that only common mode suppression techniques are used to suppress line conducted currents. This does not effect warranty or electrical safety in any way. - Original Message - From: Dan Kwok dk...@intetron.com To: Ralph Cameron ral...@igs.net Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org Sent: Monday, January 15, 2001 3:49 PM Subject: Re: Site Correlation Hello Ralph: That's a good question. At one time, I pondered the same question myself. There are obviously plenty of communication systems operating under 30 MHz. I suppose there are reasons why CISPR or CISPR 22 does not specify radiated emissions below 30 MHz. I can suggest one possibility. Perhaps others here will come up with more. For a fixed cable of length L, the ratio of L/lambda gets progressively small for frequencies much less than 30 MHz with most commercial EUTs. If we consider the cable part of dipole antenna, the reduction in frequency has a diminishing effect on the antenna's radiation resistance. Given a constant current, the radiated power would decrease with decreasing radiation resistance. At 550 KHz (bottom of the AM broadcast band in North America), the 1/4 wavelength is 136 meters. Even if the antenna's reactance is ignored, one would need very long cables driven by a significant CM noise voltage at this frequency to radiate much energy. -- Daniel Kwok Principal EMC Engineer Intetron Consulting, Inc. Vancouver, Canada Phone (604) 432-9874 Email dk...@intetron.com Web http://www.intetron.com; Ralph Cameron wrote: Ken: I like the idea of setting a limit to common mode currents on attaching cables but mI wonder why CISPR has chosen to start such measurements at 30Mhz when most of the common mode currents are the result of switching products and are generated harmonically from the fundamental and as such propagate from the low Khz range up through 30Mhz. is there no consideration for those who occupy the spectrum below 30Mhz? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Site Correlation
Ken: I like the idea of setting a limit to common mode currents on attaching cables but mI wonder why CISPR has chosen to start such measurements at 30Mhz when most of the common mode currents are the result of switching products and are generated harmonically from the fundamental and as such propagate from the low Khz range up through 30Mhz. is there no consideration for those who occupy the spectrum below 30Mhz? In my applications of common mode suppression, almost every case, the source generating the common mode currents , when suppressed with simple external common mode chokes, satisfactorily reduced all the localized radiation caused by such effects. Series common mode chokes not only suppress the outgoing but reduce the incoming common mode currents that have the same potential for casuing equipment malfunction. Ralph Cameron EMC Consulting and Suppression of Consumer Electronic Equipment (After Sale). - Original Message - From: Ken Javor ken.ja...@emccompliance.com To: David Heald dhe...@curtis-straus.com; Tudor, Allen allen_tu...@adc.com Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org Sent: Saturday, January 13, 2001 3:43 AM Subject: Re: Site Correlation I must say that this thread has been a refreshing alternative to the EMC-law/regulations questions that typically occupy this service. Not complaining either, because If I suddenly found myself working commercial EMC issues I would likely be flooding this line with those self-same questions. Almost as an aside, Mr. Heald raises an issue of enduring interest to myself and others. Another important factor... is to manipulate the cables during testing (oh, how much easier our job would be without cables). The same issue was raised parenthetically in my answer to the question about GTEM polarization. The issue is control of cable-sourced radiated emissions. I am now about to allegorically take a baseball bat to a hornets' nest... Bela Szentkuti pointed out almost twenty years ago that it would be much more efficient and accurate to analytically/experimentally determine the relationship between cable common mode currents and the resultant radiated field based on the maximum possible radiation efficiency of that cable, and use that relationship to derive a common mode current limit for cables from 30 MHz to 1 GHz, using the absorbing clamp as a measuring tool. This would speed up OATS or any other kind of RE testing by deleting the requirement to maximize cable radiation. So this question is a poll. How do the subscribers to this service feel about cable common mode current control in lieu of direct measurement of cable-sourced RE measurement? The idea being that first you would measure and bring cable cm CE into compliance with a cable-type limit and only then would you make the RE measurement. The cables would only be support equipment which did not contribute to the RE profile, hence any measured emissions at or near the limit would be guaranteed EUT enclosure-related. Polite responses only, please!!! Ken Javor -- From: David Heald dhe...@curtis-straus.com To: Tudor, Allen allen_tu...@adc.com Cc: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org Subject: Re: Site Correlation Date: Fri, Jan 12, 2001, 9:36 AM Greetings again. I received some questions about this off list and there has been more discussion in this direction, so I thought I would throw my other two cents in. For small fully anechoic chambers with little room for antenna height adjustment, you should be able to have uncertainty of about 6dB or so (10dB is much safer realistically) when you apply correction factors for a 10m site. The reason for this is, as John Barnes pointed out, the absence of reflected waves being received in addition to the direct waves. The key importance to a fully lined chamber (including the floor) is that destructive waves are not present. With a reflective floor, destructive waves can lower your readings by more than 30dB. Add this to the 6 dB or so of uncertainty for additive waves and your total error could be enormous. With an absorber lined floor, the influence of the destructive waves is eliminated or reduced, so a correlation of 6dB (again 10dB is safer) should be achievable (this simply accounts for the absence of constructive interference). Another important factor to ensure you don't have any surprises when moving from precompliance to a compliance run is to manipulate the cables during testing (oh, how much easier our job would be without cables). Large signal strength changes can be achieved just by moving cables a few inches. I also have to agree with Gert's and Ken's comments on far field measurements. I mentioned this in my original message, but didn't elaborate at all. These are very important considerations that can greatly affect any expected correlation to a 10m OATS. -- David Heald
Re: Zo
The old style B insulated wire used for telephone drops and similar lamp cord when twisted always made good balanced feedline for antennas with an impedance somewhere around 70 ohms. This assumes conductors in the range 16-18ga. a.w.g. with rubber insulation. Ralph Cameron EMC Consulting and Suppression of Consumer Electronic Equipment (After sale) - Original Message - From: William D'Orazio dora...@cae.ca To: EMC Posting (E-mail) emc-p...@majordomo.ieee.org Sent: Thursday, January 11, 2001 9:49 AM Subject: Zo Does anybody know the characteristic impedance of a twisted pair? Thanks in advance, ...OLE_Obj... William D'Orazio CAE Electronics Ltd. Electrical System Designer Phone: (514) 341-2000 (X4555) Fax: (514)340-5552 Email: dora...@cae.ca --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: CE Marking Passive devices
Thanks to all who helpfully directed me to the web site with the details. Ralph Cameron - Original Message - From: Brian Jones e...@brianjones.co.uk To: Ralph Cameron ral...@igs.net; Courtland Thomas ctho...@patton.com; emcpost emc-p...@majordomo.ieee.org Sent: Tuesday, December 12, 2000 2:39 PM Subject: Re: CE Marking Passive devices Ralph Toy Safety Directive, 88/378/EEC. For more information, have a look at www.europa.eu.int/scadplus/leg/en/lvb/121005.htm Best wishes Brian Jones EMC Consultant and Competent Body Signatory - Original Message - From: Ralph Cameron ral...@igs.net To: Courtland Thomas ctho...@patton.com; emcpost emc-p...@majordomo.ieee.org Sent: Tuesday, December 12, 2000 5:16 PM Subject: Re: CE Marking Passive devices Many passive plastic and paper toys coming from China carry the CE label. Is there a reason for it ? Ralph Cameron EMC Consultiant and Suppression of Consumer Electronics (After sale) - Original Message - From: Courtland Thomas ctho...@patton.com To: emcpost emc-p...@majordomo.ieee.org Sent: Tuesday, December 12, 2000 12:36 PM Subject: CE Marking Passive devices Hello group, I would like to know if there are any requirements for CE Marking a cable or any passive device, such as a basic surge protector. Thanks, Courtland Thomas Patton Electronics --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: CE Marking Passive devices
Many passive plastic and paper toys coming from China carry the CE label. Is there a reason for it ? Ralph Cameron EMC Consultiant and Suppression of Consumer Electronics (After sale) - Original Message - From: Courtland Thomas ctho...@patton.com To: emcpost emc-p...@majordomo.ieee.org Sent: Tuesday, December 12, 2000 12:36 PM Subject: CE Marking Passive devices Hello group, I would like to know if there are any requirements for CE Marking a cable or any passive device, such as a basic surge protector. Thanks, Courtland Thomas Patton Electronics --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: IEC 61000-3-2 -3-3
My comments re Woodgate was confsuing. What I meant to say was the transformerless SMPS s appear to generate considerable nosie as opposed to the passive transformer. Is anyone concerned about this noise? Ralph Cameron - Original Message - From: Ralph Cameron ral...@igs.net To: Dick Grobner dick.grob...@medgraph.com; IEEE EMC-PSTC E-Mail Forum (E-mail) emc-p...@majordomo.ieee.org Sent: Tuesday, November 28, 2000 11:14 PM Subject: Re: IEC 61000-3-2 -3-3 J.M.Woodgate's comments are very appropriate to identify where all the conducted noise is coming from in consumer residences but does nothing to mitigate the problem. The unfiltered SMPS used for replacement of the old reliable non noise generating physical transformer contributes little or no noise. As soon as some of these high efficiency noise (e.g. Halogen /Xenon lighting supplies) generators start truning the Samrt House concept into a Haunted House, watch the brickbats fly. Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (After sale) p.s. That goes for the trasnformerless supplies in treadmills too. - Original Message - From: Dick Grobner dick.grob...@medgraph.com To: IEEE EMC-PSTC E-Mail Forum (E-mail) emc-p...@majordomo.ieee.org Sent: Tuesday, November 28, 2000 3:50 PM Subject: IEC 61000-3-2 -3-3 At the web address below you will find an article written by J.M. Woodgate dealing with 61000-3-2 -3. This may be of interest to some on this forum as I know the issue seems to surface about every other week. Happy Reading! http://www.conformity-update.com/iec-61000-000908.htm Dick Grobner Compliance Engineering Medical Graphics Corporation 350 Oak Grove Parkway St Paul, MN 55127 651-766-3395 651-766-3389 (fax) dick.grob...@medgraph.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: IEC 61000-3-2 -3-3
J.M.Woodgate's comments are very appropriate to identify where all the conducted noise is coming from in consumer residences but does nothing to mitigate the problem. The unfiltered SMPS used for replacement of the old reliable non noise generating physical transformer contributes little or no noise. As soon as some of these high efficiency noise (e.g. Halogen /Xenon lighting supplies) generators start truning the Samrt House concept into a Haunted House, watch the brickbats fly. Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (After sale) p.s. That goes for the trasnformerless supplies in treadmills too. - Original Message - From: Dick Grobner dick.grob...@medgraph.com To: IEEE EMC-PSTC E-Mail Forum (E-mail) emc-p...@majordomo.ieee.org Sent: Tuesday, November 28, 2000 3:50 PM Subject: IEC 61000-3-2 -3-3 At the web address below you will find an article written by J.M. Woodgate dealing with 61000-3-2 -3. This may be of interest to some on this forum as I know the issue seems to surface about every other week. Happy Reading! http://www.conformity-update.com/iec-61000-000908.htm Dick Grobner Compliance Engineering Medical Graphics Corporation 350 Oak Grove Parkway St Paul, MN 55127 651-766-3395 651-766-3389 (fax) dick.grob...@medgraph.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Speed Measuring Devices
Peter: I acted as a professional witness in a similar claim that clocked a neighbour doing 110 in an 80 Km zone. The neibour lost. I attempted to prove there was the possibility of EMI from a local 50Kw broadcast transmitter which was less than 1/4 mile away. Since the reading taken is a gated reading the gun is only listening for a very few miliseconds to acquire the signal that pretty well ruled out EMI as a souce. Re the calibration. The officier was cross examined by the defendant's lawyer as to his training and qualifications that would ensure he/she knew that the rinstrument was calibrated. They simply use a tuning fork with the gun pointed at it ( one method) and it can be self calibrated. One can request at what time was the gun calibrated and what is the maximum length of time between calibrations as these things do drift over time . This particular gun operated in the 10Ghz band and was relatively new. Older units that did not take a gated reading were susceptible to errors. Another point to make is the angle at which the reading was taken. It was overlooked in the case in which I participated but there was a sharp bend in the road and there was no way my neiighbour could have been travelling at the speed claimed from the angle where the reading was taken. It cost him $1000 and some demerit points. Many judges will side with the officer when push comes to shove but at least ask the right questions and you may find yourslef believed. Ralph Cameron, EMC Consulting and Suppression of Consumer Electronics After sale) - Original Message - From: Peter Merguerian pmerguer...@itl.co.il To: emc-p...@majordomo.ieee.org Sent: Thursday, November 16, 2000 9:28 AM Subject: Speed Measuring Devices Dear All, Yes, I did get a speeding ticket today! I am not sure if I was speeding or not - I do not have my eyes on the speedometer all the time! I asked the policewoman to show me the calibration certificate on her speed measuring gun. She did not know what I was talking about! I inspected the gun and did not see any stickers on it. I plan to go to court and attempt to convince the judge that the speeding gun was not calibrated and/or the gun's measurement data may have been affected by emissions from another device. Can anyone in the calibration business send me professional opinions on the methods and reasons for calibrating speeding guns? What is the best way to present this case in court? Peter Merguerian Managing Director Product Testing Division I.T.L. (Product Testing) Ltd. Hacharoshet 26, POB 211 Or Yehuda 60251, Israel Tel: 972-3-5339022 Fax: 972-3-5339019 e-mail: pmerguer...@itl.co.il website: http://www.itl.co.il TO LEARN ABOUT AUSTRALIAN AND NEW ZEALAND REQUIREMENTS, CONTACT ME AT THE EARLIEST STAGES OF YOUR DESIGN; REQUIREMENTS CAN BE TRICKY! --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
ESD
I referred the ESD question to a good friend of mine who studied lightning and its mode of operation for many years and share this reply. Ralph Cameron EMC Consultant and Suppression of Consumer Electronics (After Sale)
Re: Electron Flow
Ross: I'm with you. The earth represents the reference plane so the charge actually moves from the earth to the cloud to neutralize it. Ralph Cameron - Original Message - From: Hunt, Richard rh...@canoga.com To: 'Lichtenstein, Ross' ross.lichtenst...@owenscorning.com; 'Barry Ma' barry...@altavista.com; emc-p...@majordomo.ieee.org Sent: Thursday, October 05, 2000 12:23 PM Subject: RE: Electron Flow Here we go...this ought to be good. Richard Hunt Engineering Services Manager Direct: (818) 678-3860 Canoga Perkins Corp. Main:(818) 718-6300 20600 Prairie Street FAX: (818) 678-3760 Chatsworth CA 91311-6008 e-mail: rh...@canoga.com rh...@canoga.com -Original Message- From: Lichtenstein, Ross [mailto:ross.lichtenst...@owenscorning.com] Sent: Thursday, October 05, 2000 7:54 AM To: 'Barry Ma'; emc-p...@majordomo.ieee.org Subject: RE: Electron Flow Barry, I could be wrong, and if so I would stand corrected, but from my basic electronics training, I recall that electron flow is from negative to positive. I also recall being taught that lightning actually travels from earth (neg. charge) upward to the positive charge of the clouds. Then there is also the case of lightning between clouds of opposite charge, and again the electron flow direction is from neg. to pos. Ross -Original Message- From: Barry Ma [mailto:barry...@altavista.com] Sent: Wednesday, October 04, 2000 5:58 PM To: emc-p...@majordomo.ieee.org Subject: Re: ESD Opportunities Please allow me to ask a relevant question only for curiosity. We have no idea of what charge (positive or negative) would go to the DUT in ordinary ESD. That's why we have to test two polarities in ESD immunity test. Lightning is a kind of ESD happened between a charged cloud and objects on earth surface. Some figures imply that an electron current flows from the charged cloud to the earth. Is it possible to have an opposite direction - electron flows from earth to cloud? Thanks. Barry Ma ___ Free Unlimited Internet Access! Try it now! http://www.zdnet.com/downloads/altavista/index.html ___ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Power Line Voltages
Reference Data for Engineers has this information. A local library would have it. Ralph Cameron EMC Consulting and Suppression of Consumer Electronic Equipment (After Sale) - Original Message - From: Flinders, Randall randall.flind...@emulex.com To: emc-pstc emc-p...@majordomo.ieee.org Sent: Wednesday, October 04, 2000 8:00 PM Subject: Power Line Voltages Greetings group! I am looking for a resource, preferrably but not neccessarily on the web, were I can get all of the power line voltages and frequencies for every country. This includes Europe, The Pac Rim, Autralia, Africa, Middle East, etc Can anyone direct me to this information? Any help would be greatly appreciated! Regards, Randy Flinders EMC Engineer Emulex Corp. r.flind...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Leakage Current Measurements
Ken: Analog meters are inherently good low pass filters and will mask any high frequency components. The same is truefor most DMMs unless they have been specified for higher frequencies. Typically, don't expect much accuracy beyond 100Khz for soem of the best DMMs. You can always use a scope with adequate bandwidth if you susepct high frequency conducted components. That way, you can not only identify whether noise is present but its waveshape. Any changes to make to reduce the noise are readily visible. RF power meterssuffer from the same deficiency unless specifically rated and designed for pulsed waveform measurments. I recall an evaluation done my our Dept of National Defence that found many gross errors in instruments not designed or compensated for narrow pulses. As mentioned on this forum, check for a true rms voltmeter function and assure yourself what kind of accuracy you're getting at the highest frequencies of interest. If you can live with 5-10% error - go for it. Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment ( After sale) - Original Message - From: Matsuda, Ken matsu...@curtisinst.com To: emc-p...@majordomo.ieee.org Sent: Tuesday, October 03, 2000 3:44 PM Subject: Leakage Current Measurements I found something interesting today. While measuring leakage current with a digital multimeter, I noticed a high amount of leakage. The unit incorporates a switching power supply, with some EMI/EMC circuitry. Anyhow, I read somewhere that DMMs are some times inaccurate with high frequency line conducted emissions. Took a old Simpson analog meter (took forever to figure it out, since I've never touched a analog meter hehehe) and found measurements that were rather low. The questions is, I'm wondering if UL or for that matter, any other testing agency actually know about this fact, or merely fail their clients with incorrect data. Any input on this subject would be appreciated. Ken --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: ESD Opportunities
Try an internet search on electrostatic dischareg and you will finf there are hundreds of papers on the subject. Merely rubbing your hand across wool or cloth or a waxed desk and garbbing an electronic device will cause ESD . Hold a pocket calculator in your hand while you rub your hand against your pant leg and /or shuffle your shoes across a rug and lay your hand on the LCD display. If there's no ESD protection - the LCD display will blank. - caused by charge dispersal. Most modern electronic test equipment manufactured in North America is protected to 10Kv ESD disharge anywhere on the outdide of the intrument for the same reason. In the case of a cell phone it used to be possible to blow the front end by holding on to the antenna after charging up some part of the body through friction. In wintertime the problem is very bad in contacting computing equipment. When you find the CE mark on computer equipment you may be assured that it will at least have some immunity to both ESD and radiated and conducted currents. Obviously, the time to incorporate either ESD immunity or EMC is at the design stage. Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment (After Sale) - Original Message - From: appengr...@aol.com To: litlkim2...@hotmail.com; emc-p...@majordomo.ieee.org Sent: Wednesday, October 04, 2000 12:02 AM Subject: Re: ESD Opportunities ESD is a term used for an electrical discharge that occurs from one charged surface to another un-charged surface usually generated by frictional or triboelectric effects. I have never heard of ESD issues within cell phones or LCD displays. It may be possible that a person with a large charge build up on their bodies could discharge into the phone when they touch the phone, or possibly the phone could have a charge that could discharge into your hand, but in either case it seems very unlikely that an electrical discharge would happen or if it did that it would have much effect on the cell phone or display. Have you ever heard of ESD being an issue? Outside of good EMC/EMI practices I am not sure where or what could be done to prevent ESD. Maybe others on the list may have some insight into this issue. I am doing a graduate research project on the ESD opportunities that exist in the telecom market, specifically cell phones and laptops that have LCD's which are affected by ESD. Is this a market to look into, and what are the requirements and trends that you see going on? What materials or solutions are currently being used to address ESD problems in these systems, and are they they working? Lastly, is ESD a factor that is considered when designing EMI shielding solutions? I would appreciate any insight you may have. Thanks! kl --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Probing power plane with analyser.
Cameron: That's fairly easy to do as long as you: 1. Take all measurments from the same reference points before and after the changes and 2. Use a DC block on the input to the analyzer ;other wise you may have an expensive input to replace. Most analyzers inputs are not protected for DC. Most companies sell the DC isolator as an accessory. Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment. - Original Message - From: Cameron O'phee O'p...@ali.com.au To: 'EMC - PSTC Forum' emc-p...@majordomo.ieee.org Cc: Roman Seifert seif...@ali.com.au Sent: Wednesday, September 27, 2000 8:59 PM Subject: Probing power plane with analyser. Hello All, I have been asked by one of our design engineers if I can measure the RF signature on the 3v plane on one of our PCB designs. The purpose of this is to compare it to proposed changes for cost reduction, ie removal of bypass caps. I would assume I need some sort of CDN but I have no designs for this application. Does anyone have any ideas on how I can safely probe a 3v DC power rail with an EMC analyser (HP8591E)? Regards, Cameron O'Phee. EMC Safety Precompliance. Aristocrat Technologies Australia. Telephone : +61 2 9697 4420 Facsimile : +61 2 9663 1412 Mobile : 0418 464 016 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Re[3]: Battery Safety
Barry: This is the same principal used to charge the batteries for the artificial heart- an inductive loop. Ralph Cameron - Original Message - From: Barry Ma barry...@altavista.com To: eric.petitpie...@pulse.com Cc: emc-p...@ieee.org Sent: Tuesday, September 26, 2000 8:26 PM Subject: Re: Re[3]: Battery Safety Eric, Thanks for the nice answer. Barry Ma - On Tue, 26 September 2000, Eric Petitpierre wrote: Barry, There is likely an excitation coil in the base. I sends out a magnetic field. The recever, (toothbrush) has a receive coil that charges the battery. In other words, the primary of the transformer is in the base. The secondary of the transformer is in the toothbrush. When the toothbrush is in the base, the proximity is close enough to charge the battery. Eric Petitpierre ___ ___ Free Unlimited Internet Access! Try it now! http://www.zdnet.com/downloads/altavista/index.html ___ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Battery Safety
Chris: Is the battery a rechargeable? Have you tried disconnecting the 91K reisstor and measuring the resulting voltage increase? Doesn't make sense to me. Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (After sale) - Original Message - From: Maxwell, Chris chr...@gnlp.com To: 'EMC-PSTC Internet Forum' emc-p...@majordomo.ieee.org Sent: Monday, September 25, 2000 11:30 AM Subject: Battery Safety All, We have inherited a design from a company which we purchased. The product is a handheld and can be operated from a pair of Alkaline batteries. Inside the unit, there is a 91 KOhm resistor across the + and - terminals of the batteries. Since the people who designed the instrument are long gone, some of my collegues have asked me if this resistor could be a safety feature. I can't think of any way this resistor would help the safety of the instrument. I did read through the safety test report; and I found no reference to this resistor being required. All it does is provide a constant drain on the battery (reducing battery life). It has been suggested to me that some designers put resistors across batteries to reduce the electrical noise in a product. To me a capacitor would be better for this because it wouldn't drain the battery while it was filtering. Even so, isn't a battery the ultimate capacitor? I'm just drawing a blank why anyone would do this. I'd love to recommend that we pull this resistor out because it's a pain to solder and it affects battery life. However, I don't want to sacrifice the safety of the product. Anybody want to take a guess at this one? Thanks. Chris Maxwell, Design Engineer GN Nettest Optical Division 6 Rhoads Drive, Building 4 Utica, NY 13502 PH: 315-797-4449 FAX: 315-797-8024 EMAIL: chr...@gnlp.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Component Qualification
Tony: I have sold these systems and also used them and they are good for graphing a profile of a scanned board and giving the field intensity vs postion over the board area. You can quickly find trouble spots using the computer interface. Ralph Cameron - Original Message - From: Tony J. O'Hara tonyoh...@compuserve.com To: Koh Nai Ghee koh...@cyberway.com.sg Cc: EMC-PSTC emc-p...@majordomo.ieee.org Sent: Wednesday, September 20, 2000 4:42 PM Subject: Re: Component Qualification You may want to look at using a PCB Electromagnetic Scanning System! One of the advertised uses for these test devices is for quickly comparing EMC performance when component changes are made etc.! I believe there are 4 different manufacturers who make these devices. The one that I'm just starting to learn about is made by EMSCAN in Canada. Their web is www.emscan.com Maybe someone who has uses one of these scanners can provide an experienced viewpoint? Regards Tony Colorado --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Component Qualification
Chris, Don't get me wrong. I didn't read the full text of the application and merely supported the utility of the EMSCAN system. If you know of sources where you cn get ferrites, specifically ferrite toroids for a dime a dump truck, I'd be interested. In the past two years my costs for them have more than tripled as the mfr now uses dealers who have minu\imum quantities which are out of sight for the small vendor. With the heavier weights , shipping costs skyrocket. I like your methods of determining ferrite application and how to look for hpt spots. My opinions are my own since I work for me. regards Ralph Cameron EMC Consultant and Suppression of Consumer Elecronics (after sale). - Original Message - From: Maxwell, Chris chr...@gnlp.com To: 'Ralph Cameron' ral...@igs.net; Tony J. O'Hara tonyoh...@compuserve.com; Koh Nai Ghee koh...@cyberway.com.sg Cc: EMC-PSTC emc-p...@majordomo.ieee.org Sent: Thursday, September 21, 2000 7:58 AM Subject: RE: Component Qualification Wait a minute! Buying a board scanning system to evaluate different vendors for ferrites and oscillators? My company doesn't have that kind of money to throw around. These systems can cost 10's of thousands of dollars. Ferrite beads cost about a dime for a dump truck load. If it costs $10,000 to evaluate a second source for ferrites, I 'll stick with the ferrites I have. I'd like to offer a lower cost alternative. Koh Nai asked about what specifications were important for qualifying alternate sources for ferrites and oscillators. When it comes to ferrites, I look at three things: I look at the PCB footprint (it won't work if it won't fit). I look at the impedance curve and the current capacity. If all three of these specifications are equal or better than what I need, I accept them. I don't even consider re-testing for emissions if I have checked these three specifications. Alternate sources for ferrites can be qualified for the cost of reading a spec sheet. Oscillators are a different story. When one of my digital design colleagues wants to change oscillators. They consider its PCB footprint, the output frequency, its ambient stability, its temperature stability and its load driving capability. If it meets their needs; then I take a circuitboard with the existing oscillator and run a near field probe over it near the oscillator until if find a location of maximum near field emissions. (If you really are strapped for cash, you can make your own near field probe.) I write down the exact position and orientation of the near field probe and I either print out or write down the spectrum analyzer readings. I then put the new oscillator on the exact same board and repeat the experiment. If the measurements are close (within a dB or two) I don't worry. If the measurements are more than 4 dB higher, then I look further. Then I consider: testing the whole unit with the new oscillator with my antenna set up 1 meter away in-house, or re-testing the unit for emissions at an OATS, or not using the new oscillator. ONE WARNING: if the new oscillator is at a different frequency, then the method above WILL NOT yield any useful results. One thing that we have done with new designs is to put a 1206 surface mount PCB footprint in line with the oscillator output. We start our testing with a 0 ohm resistor. If we run into problems, we can put either a ferrite bead or higher value resistor in this position to cool off the oscillator. This has worked well with oscillators under 100MHz. I don't know if it will work for faster oscillator. I know that there are problems with using near field probes to make such correlations, however using a board scanning device would cost much more than a near field probe and still only be measuring near fields. Even so, if I had the budget, I'd love to try one out. To me, the real method of doing this starts with the initial testing of your product. I try to get more than a 5dB margin during the initial testing. With these margins, I don't need to worry so much about component differences. I know that this is sometimes not possible. I have sacrificed margins in order to get a product's testing done and released (I don't get paid if we don't ship.) The problem is, without margins, I need to worry more about component differences. Another point to remember is that EN 55022 and other emissions standards go by the 80 % rule. A product passes if we are confident that 80% of the units that we ship meet the emissions requirements. Anybody who wants to dispute whether your units pass or not is REQUIRED to test up to 7 samples in order to get enough data to use statistical methods to compute the confidence factor. One failing unit does not equal a guilty verdict. (Of course, if one unit is failing by 20dB, that's a problem.) The people at CISPR put this slack into the limits to allow for slight component differences
Re: Supplies of HV Rectifiers
Brian: You can obtain the HV rectifiers from K2AW's Silicon Alley 175 Friends Lane Westbury NY. 11590 Tel/Fax 516-334-7024 e-mail : silicona...@aol.com He stocks rectifiers to 14KV PIV with Max Fwd Avg Current to 1000 ma. and Max Fwd Peak Surge Current of 250A Prices run about $14 each U.S. He carries lower voltages also at correspondingly less money. Ralph Cameron EMC Consultant and Suppression of Consumer Electronics (After Sale) - Original Message - From: Brian Harlowe brian.harl...@vgscientific.com To: emc-p...@ieee.org Sent: Tuesday, September 19, 2000 10:04 AM Subject: Supplies of HV Rectifiers I apologise that this question is outside the remit of this group but I am in a desperate situation and with the wealth of experience there is out there I hope some one can help me. We have manufactured in the past an X. Ray power supply that gets its EHT from a rectified three phase supply. Because all you whizzy electronic engineers are now using multipliers to make high voltage. Rectifiers that can handle 7-8kV at up to 20mA are getting like Rocking Horse manure to obtain in the UK. My question is can anyone point me in the direction of a supplier in the US or Far East of such beasts Many thanks in advance Brian Harlowe Brian Harlowe V.G. Scientific Tel +44 (0)1342 327211 Fax +44 (0)1342 315074 Received: from ruebert.ieee.org ([199.172.136.3]) by mail.monarch.com with SMTP (IMA Internet Exchange 3.14) id 8C60; Tue, 19 Sep 2000 09:23:29 -0700 Received: by ruebert.ieee.org (8.9.3/8.9.3)id JAA17554 Received: from engine.ieee.org by ruebert.ieee.org (8.9.3/8.9.3) with ESMTP id JAA17540; Tue, 19 Sep 2000 09:25:25 -0400 (EDT) Received: from gemini2.ieee.org (gemini2.ieee.org [199.172.136.19]) by engine.ieee.org (Switch-2.0.6/Switch-2.0.1) with ESMTP id e8JDPLZ27172 for emc-p...@ieee.org; Tue, 19 Sep 2000 09:25:21 -0400 (EDT) Received: from kestrel.vgscientific.com ([193.130.56.103]) by gemini2.ieee.org (8.9.3/8.9.3) with ESMTP id JAA15261 for emc-p...@ieee.org; Tue, 19 Sep 2000 09:25:17 -0400 (EDT) Received: by KESTREL with Internet Mail Service (5.5.2650.21) id TAPNHT2J; Tue, 19 Sep 2000 14:29:01 +0100 Message-ID: F9D85B6AF82BD4119AE800D0B769603B0A10A2@KESTREL From: Brian Harlowe brian.harl...@vgscientific.com To: 'emc-p...@ieee.org' emc-p...@ieee.org Subject: Help Date: Tue, 19 Sep 2000 14:28:59 +0100 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain X-Resent-To: emc-pstc-ad...@ieee.org Precedence: bulk --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
schematic
Low level halogen and Xenon lighting make use of electronic transformers. Does anyone have a typical circuit of one of these transformers? I attempt to do suppression of devices such as these that generate considerable broad band noise at broadcast as well as short wave frequencies and need to know what is causing the conducted distortion to feed back to the powerline. I am told by producers of these noise generators that most producers use the the same or a similar circuit. I believe SCRs or unstabilized switch mode supplies are the culprits. Any help would be appreciated. Ralph Cameron EMC Consultant for Suppression of Consumer Electronics ( after sale)
Re: R: Conducted Emissions on Telecom Ports
Steve: Please tell me more about the immunity standards- they are non existent in Canada Ralph Cameron EMC Consulting and Suppression of Consumer Electronic Equipment (After sale) p.s Ever listen to the radio near some home treadmills? - Original Message - From: Steve Grobe ste...@transition.com To: ieee pstc list emc-p...@ieee.org Sent: Thursday, September 07, 2000 1:35 PM Subject: RE: R: Conducted Emissions on Telecom Ports Has anyone seen problems with ethernet and conducted emissions? I have a home office with 4 PCs networked with ethernet running over UTP and I haven't seen much of a problem. Granted, the longest cable run I have is to a file server in the basement (about 10 meters) but both my AM radio and my shortwave set seem to work just fine. The only thing I remember picking up is 20MHz on the shortwave set. (Most 10Mbit ethernet devices use a 20MHz clock.) At work we have both 10 and 100Mbit ethernet (150-200 nodes) and the AM reception is really bad but I attribute that to the building (big steel and brick box) more than noise as reception improves as you get closer to a window. I haven't tried the shortwave at work being that shortwave reception is usually bad during the day anyway. As far as telephone lines are concerned my ears don't pick up much noise above 19kHz. I would think anything else would be covered by immunity standards. Steve -Original Message- From: Cortland Richmond [mailto:72146@compuserve.com] Sent: Thursday, September 07, 2000 11:01 AM To: Paolo Roncone; ieee pstc list Subject: Re: R: Conducted Emissions on Telecom Ports Paolo Roncone wrote: The scope of emissions standard should be to protect the outside (i.e. public) environment from interference. So only ports that connect to public telecom networks should be covered by the standard. I disagree. The purpose of emissions standards is to prevent interference. Some are to similar functions, some are to other media. There is no interface for interference at which point the manufacturer may say: Interference when you use this isn't our problem. We may say: Use shielded cable, or Put a ferrite on your cable, but we can't evade the physical fact that it is our own equipment which is the source of interference, and the cable is its antenna. It does not matter that we do not own the cable; if you plug it in and there is interference, it is up to the people who made the equipment to see the interference reduced. There is no transfer of ownership for radio waves. Granted, to call a LAN cable telecommunications is a clumsy construction of the regulation. But those who grasp at that straw to save a few currency units will find themselves later regretting that they have done so. If you are beaten and robbed for a display of wealth, it is no use protesting that the money was counterfeit. Cortland Richmond (I speak for myself alone and not for my employer) == Original Message Follows Date: 07-Sep-00 07:48:16 MsgID: 1072-46656 ToID: 72146,373 From: Paolo Roncone INTERNET:paolo.ronc...@compuprint.it Subj: R: Conducted Emissions on Telecom Ports Chrg: $0.00 Imp: Norm Sens: StdReceipt: NoParts: 1 From: Paolo Roncone paolo.ronc...@compuprint.it Subject: R: Conducted Emissions on Telecom Ports Date: Thu, 7 Sep 2000 16:45:03 +0200 Reply-To: Paolo Roncone paolo.ronc...@compuprint.it Hi Eric, I 100% agree with you. The scope of emissions standard should be to protect the outside (i.e. public) environment from interference. So only ports that connect to public telecom networks should be covered by the standard. The problem is (as pointed out in one of the previous notes) that the new CISPR22 / EN55022 standard clearly includes LAN ports in the definition of telecommunications ports (section 3.6) no matter if they connect to the outside world or not. Regards, Paolo Roncone Compuprint s.p.a. Italy -Messaggio originale- Da: eric.lif...@ni.com [SMTP:eric.lif...@ni.com] Inviato:mercoledì 6 settembre 2000 17.55 A: emc-p...@ieee.org Oggetto:Re: Conducted Emissions on Telecom Ports All, As a not-quite-outside-observer (strictly EN 55011 here) of this thread, it's not fun seeing LAN ports classified as telecom; IMO that's overkill for the folks using EN 55022. Up till now, I considered a port to be telecom only if it connects a client facility to a carrier's network (DSL, ISDN, T1 and so on). With repeaters every 5 meters, USB and 1394 can support a bus long enough to connect between adjacent buildings. So, I wonder if some fanatic will soon be promoting USB/1394 ports as telecom? If Chris is right, and the EN 55022 version of the old telecom port conducted emission standard was intended to protect other telecom signals in a bundle, then I would think that this test is clearly redundant to the immunity
Re: RF Immunity levels
DB What physical volumes are needed for containing the EUT ? Ralph Cameron - Original Message - From: Brumbaugh, David david.brumba...@pss.boeing.com To: 'emc-pstc' emc-p...@ieee.org Sent: Tuesday, August 01, 2000 7:37 PM Subject: RF Immunity levels Hi, group Here's a question for you test lab folks out there, or anyone familiar with current test lab capabities - What are the maximum E field levels achievable between 2 GHz and 40 GHz? I'm looking for a maximum at each frequency (narrowband nulls excluded). Even if peak levels at discrete frequencies are all that can be achieved, I'd like to know that, too. I'd appreciate a test house contact in the US if anyone has an answer. Thanks, DB --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Electrical safety of firearms
I think if ther is an electronic circuit that activates the triggering device and that circuit lacks EMC , it has the potential to malfunction. If the electronic ciruit is the one to commence the action of firing without any electrical interface then it had better perform its intended funtion in the presence of strong radiated fiields. I didn't read EED into what Phil mentioned and I would certainly agree that ESD needs consideration. I would expect too that the intended use may have a bearing on what safety measures are imperative. Ralph Cameron EMC Consultant for Suppression of Consumer Electronics (After sale) - Original Message - From: Ken Javor ken.ja...@emccompliance.com To: Ralph Cameron ral...@igs.net; pgodf...@icomply.com; emc-p...@majordomo.ieee.org Sent: Thursday, July 27, 2000 12:31 AM Subject: Re: Electrical safety of firearms I think both Mr. Firth and Mr. Cameron are confusing ordnance activated by an electro-explosive device (EED) with ordinary bullets. In the case of an EED, it is very important to not only provide safe and arm capability, but also to ensure that field-to-wire coupling does not inadvertently inject enough electrical energy to set off the EED. This concern is addressed in such documents as MIL-STD-1385, MIL-STD-1512, MIL-E-6051D and MIL-STD-464. Together, these standards define no-fire and all-fire levels, and EMC safety margins X dB below the no-fire level. But none of this would apply to a trigger, hammer and powder-loaded cartridge based system. There is no electrical interface to the cartridge, hence no need for safety margins, etc. I assume that the only difference between the electronic trigger and a conventional trigger is that there is no mechanical linkage between trigger and hammer - the trigger applies electrical potential to a solenoid, which ejects a hammer substitute into the cartridge base. I would want a solenoid that operated at a high enough potential and drew enough current that the field-to-wire pickup from even the strongest possible nearby field would be insufficient to energize the solenoid. And the solenoid would require several milliseconds of applied power, so that a short duration pulse (ESD, EFT) could not trip the hammer. Any additional safety interlock would be a mechanical switch. If you get fancy and start putting 3 or 5 Volt logic in this thing, then you open yourself up to ESD and any number of other problems. In today's atmosphere where even ordinary firearms are viewed as defective products, imagine the ruckus some lawyer could cause with a twenty five year old handgun in which an old battery corroded and caused enough degradation that the gun malfunctioned and fired without a pull of the trigger. It would matter not that the gun had been sold and resold or stolen and resold. In fact, they could make the case that the nth owner is less likely to understand the thing than the original buyer. It's not paranoia if they really are following you... -- From: Ralph Cameron ral...@igs.net To: pgodf...@icomply.com, emc-p...@majordomo.ieee.org Subject: Re: Electrical safety of firearms Date: Wed, Jul 26, 2000, 8:40 PM Phil: I would hope that the electronic trigger cisrcuit has been designed with EMC in mind. Not like the Toronado aircraft that had its munitions explode whennflying too close to a local European trasnmitter. Ralph Cameron EMC Consultant for Suppression of Consumer Electronics ( After Sale). - Original Message - From: pgodf...@icomply.com To: emc-p...@majordomo.ieee.org Sent: Wednesday, July 26, 2000 3:50 PM Subject: Electrical safety of firearms Here's one that you feel should have something, just because of the nature of the equipment, but your not quite sure what!! Does anyone have the least inkling of any safety requirements specific to a firearm with an electronic trigger. I am not particularly interested in firearms laws/regulations etc but any requirements that the electronics may fall under. This device will be powered by a 9-volt battery. Thanks in advance of any responses. Phil Godfrey ps. Domestic, EU, Aus and a few more. Thanks Phillip Godfrey - Manager, Product Safety KTL Dallas, Inc. 802, N.Kealy, Lewisville, Texas 75057-3136 Tel : (972) 436-9600 Fax: (972) 436-2667 http://www.ktl.com/ email : pgodf...@icomply.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: 8591EM monitor output
Jeff: Radio Shack sells an RF modulator that will do the job. If you feed it to a VCR you can also record the results as well as view it on a TV set. As mentioned, it produces NTSC compatible video on CH3 or 4. Price should be around $25. U.S. Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (after sale). - Original Message - From: Scott Lacey sco...@world.std.com To: Jim Bacher jim_bac...@mail.monarch.com Cc: emc-p...@ieee.org Sent: Monday, July 24, 2000 6:29 PM Subject: RE: 8591EM monitor output Jeff, I think the piece of hardware you need is an RF Modulator. These output your video on Channel 3 (sometimes switchable to channel 4). Should be available for $25-$50 dollars. Try MCM Electronics (800 543-4330)if you can't find one locally. The one I have is their P/N 33-1480 Audio/Video Modulator. It is about 3 x 5 x 1, with an attached (120V) line cord, and a switch to select CH3/CH4. Scott Lacey -Original Message- From: owner-emc-p...@ieee.org [mailto:owner-emc-p...@ieee.org]On Behalf Of Jim Bacher Sent: Monday, July 24, 2000 3:42 PM To: Bailey; Jeff; 'emc-pstc' Subject: Fwd:8591EM monitor output forwarding for Jeff. Reply Separator Subject:8591EM monitor output Author: Bailey; Jeff jbai...@mysst.com Date: 7/24/00 12:06 PM Hello all, Have any of you successfully hooked up a television to an HP8590 series EMC analyzer? The monitor output does provide NTSC format, I am now assuming that I need to provide a carrier for the monitor output to ride on in order for the TV to see the NTSC signal and know what to do with it. Is there an easier way to do this than to build my own modulator? Thanks, Jeff Bailey Compliance Engineering SST - A Division of Woodhead Canada Phone: (519) 725 5136 ext. 363 Fax: (519) 725 1515 Email: jbai...@sstech.on.ca Web: www.sstech.on.ca --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Adjacent Channel Power Measuring Equipment
Paul: Tektronix has a good application note covering measurement of adjacent channel power. I am not sure but I don't think the 8566B can be triggered to perform such measurements, I've been away from the field a little too long . Tek markets the Rhode and Schwartz products and most modern spectrum analyzers have that capability. A call to the local office should get you some help. Ralph Cameron EMC Consultant forSuppression of Consumer Electronics (After sale) - Original Message - From: Paul Slavens paul_slav...@hotmail.com To: emc-p...@ieee.org Sent: Wednesday, June 28, 2000 5:28 PM Subject: Adjacent Channel Power Measuring Equipment Hello Group, I am having a little trouble with section 8.5 (adjacent channel power) of ETSI EN 300 220-1. Specifically, I am having difficulty understanding the requirements for the power-measuring receiver defined in Annex B. My questions are: 1. Is the HP EMI rack, consisting of an 8566B spectrum analyzer, an 85685A RF pre-selector, and an 85650A quasi-peak adapter a suitable instrument for making adjacent channel power measurements? 2. If the HP EMI rack will not properly measure adjacent channel power per ETSI EN 300 220-1, what instrument or instruments will? If anyone could help shed a little light on the above question, I would be most thankful. Regards, Paul Slavens Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: MITI/Dentori-T
George: I read some Japanese but do not know the meaning of dentori unless it is a compound of two other nouns. I would say, dentori because there is no Y in the Japanese syllabry. Japanese are quite flexible in their phonetic liberties particularly when appealing to an English speaker. Ralph Cameron EMC Consultant for the Suppresion of Consumer Electronics (After Sale) - Original Message - From: geor...@lexmark.com To: emc-p...@majordomo.ieee.org Sent: Tuesday, June 20, 2000 11:13 AM Subject: MITI/Dentori-T Dumb question: I've used the term Dentori-T mark when referring to the Japan mark authorized by MITI. Lately I have seen this spelled as Dentory, even on foils presented by Japanese companies. I am confused. Which is the correct spelling: Dentori or Dentory George Alspaugh --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Measuring noise, spectrum analyzer
Ron Tektronix has some application notes for using spectrum analyzers in measuring CDMA signals which would apply to OATS sites. You may want to contact their local office as the notes are free. They may even be available on their web site Ralph Cameron EMC Consultant for Suppression of Consumer Electronics (After sale) - Original Message - From: ron_cher...@densolabs.com To: emc-p...@ieee.org Cc: rcher...@home.com Sent: Monday, June 19, 2000 3:41 PM Subject: Measuring noise, spectrum analyzer I am looking for information or articles written on measuring a CDMA or noise-like signal with a spectrum analyzer. I will be doing EIRP measurements on an OATS. Thanks in advance, Ron Chernus, DENSO --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Looking For Video Pattern Generator
Eric, Give Teltronix a call. They used to have such an instrument. Ralph Cameron EMC Consultant for Suppression of Consumer Electronics (After Sale) (and retired Tek emploee) - Original Message - From: eric.lif...@ni.com To: emc-p...@ieee.org Sent: Thursday, June 08, 2000 2:08 PM Subject: Looking For Video Pattern Generator Hello Listers, We're looking for a stand-alone video pattern generator (both PAL and NTSC formats) to test video capture boards for the EMC Directive; and, hopefully the generator itself would pass too. We need one that would include a display of time so we can detect a lack of trigger or frozen acquire. Any suggestions? Regards, Eric Lifsey National Instruments --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Smoke Alarms
Not sure if this is apprpriate for this group. Can anyone tell me what the audible requirements are for standard approved smoke alarms? Is there a spec for them ? Mny seniors have difficulty hearing a high pitched tone and I am attempting to determine alternatives. Thanks Ralph Cameron EMC Consultant for Suppression of Consumer Electronics (After sale)
Re: interference to Comm devices due to overhead catenaries
Susan: Are the catenaries enrgized? In any event you can expect some signal degradation and perhaps complete cancellation as the locomotive moves becuase the catenaries will screen the GPS signals. As you may be aware, GPS relies on a minimum of two visible satellite signals and sometimes is able to see six or more which makes accuracy more achievable. Any metallic medium interspersed between the GPS antenna and the direct satellite signal will cause a certain attenuation to the signal. Can you provide more specifics? Ralph Cameron EMC Consultant for Suppression of Consumer Electronics (After Sale) - Original Message - From: Beard, Susan sbe...@ge-harris.com To: emc-p...@ieee.org Sent: Tuesday, May 23, 2000 3:56 PM Subject: interference to Comm devices due to overhead catenaries Could anyone provide any information relative to overhead catenary noise and its affects on locomotive roof top comm systems (e.g., GPS)? Susan Beard --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Charge moving from decoupling capacitors
Barry Thanks for correcting me. Practical solutions have changed from the time I made many measurements on PCBs with discrete components. I'll be interested to read the article you mentioned since I wasn't aware a single SMA cap could do a better job. Regards, Ralph Cameron - Original Message - From: Barry Ma barry...@altavista.com To: ral...@igs.net Cc: emc-p...@ieee.org Sent: Friday, May 19, 2000 11:33 AM Subject: Re: Charge moving from decoupling capacitors Ralph, Please be cautious about what you said below: the reason why most power buses on PCBs use several values of decoupling is to ensure that a wide range of frequencies are covered. Several V curves shown in the figure of impedance vs. frequency, which we are all familiar with, would easily convince us the above statement. But those V curves only show the absolute value of impedance around self-resonance frequency of various capacitors. If considering related phase relations, the total impedance of several values of decaps would become not as simple as we expected - having low impedance over wider frequecy range. You may refer to an article by Paul, C. R.: Effectiveness of multiple decoupling capacitors, IEEE EMC Vol. 34, p. 130, May 1992. In my practice of using SMA caps, only the largest value of capacitance available for given SMA size is selected, if I have a PCB with 10 mil or less plane spacing. Regards, Barry Ma b...@anritsu.com On Thu, 18 May 2000, Ralph Cameron wrote: As I read in an article related to bypassing for good decoupling ( in 1971) one can select from a number of EIA values and by cutting the lead lengths correctly ( e.g. from 1/2- less than 1/4 ) the series reonant frequency will drop by a considerable amount so - yes, the reason why most power buses on PCBs use several values of decoupling is to ensure that a wide range of requencies are covered. Perhaps, with surface mount caps, that is easier to predict because they are essentially leadless. I once cured a very severe case of an FM receiver responding to the 7th harmonic of a 14Mhz transmitter because an untuned mixer was used. Placing a 100pf cap with 1/4 leads right across the mixer IC completely cured the problem without degrading mixer sensitivity. Ralph Cameron EMC Consultant for Suppression of Consumer Electronics (After Sale) ___ Why pay when you don't have to? Get AltaVista Free Internet Access now! http://jump.altavista.com/freeaccess4.go ___ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Re:RE: Charge moving from decoupling capacitors
As I read in an article related to bypassing for good decoupling ( in 1971) one can select from a number of EIA values and by cutting the lead lengths correctly ( e.g. from 1/2- less than 1/4 ) the series reonant frequency will drop by a considerable amount so - yes, the reason why most power buses on PCBs use several values of decoupling is to ensure that a wide range of requencies are covered. Perhaps, with surface mount caps, that is easier to predict because they are essentially leadless. I once cured a very severe case of an FM receiver responding to the 7th harmonic of a 14Mhz transmitter because an untuned mixer was used. Placing a 100pf cap with 1/4 leads right across the mixer IC completely cured the problem without degrading mixer sensitivity. Ralph Cameron EMC Consultant for Suppression of Consumer Electronics (After Sale) - Original Message - From: Jim Bacher jim_bac...@mail.monarch.com To: george_t...@dell.com Cc: emc-p...@ieee.org Sent: Thursday, May 18, 2000 4:24 PM Subject: Re:RE: Charge moving from decoupling capacitors Forwarded for George. Reply Separator Subject:RE: Charge moving from decoupling capacitors Author: george_t...@dell.com Date: 5/18/00 2:30 PM Barry, Thanks for the comments. Here are my comments: Ok, you put caps at a certain distance away from the IC because you only want them to work at 100 MHz. But that distance turns out to be the 1/4 wave distance at 400 MHz, and you placed enough caps at the 1/4 wave distance to cause board resonance. Now what? Do you tell the caps not to work at 400 MHz because it's not their frequency? For your 2nd comment: I used the words loosely define for that reason. If you are interested in high frequency decoupling and instantaneous current, you really want to have all your charges moving in phase. At 1/4 wavelength, the charges are 90 degrees out of phase, so they will not do much for your instantaneous current. 1/8 wavelength is what I consider to be acceptable. You can certainly pick a different number. Regards, George Tang george_t...@dell.com -Original Message- From: Barry Ma [mailto:barry...@altavista.com] Sent: Thursday, May 18, 2000 10:50 AM To: george_t...@exchange.dell.com Cc: si-l...@silab.eng.sun.com; emc-p...@ieee.org Subject: RE: Charge moving from decoupling capacitors George, Thanks for your long input. I'd like to make some comments below. - On Wed, 17 May 2000, george_t...@dell.com wrote: Large parallel plates behave as transmission lines. A quarter wavelength transmission line with a short at the end has infinite impedance, so capacitors placed 1/4 wavelength away are bad. That's why decaps work on low frequency portion. Let's set 100 MHz and below for decaps to cover. The wavelength at 100 MHz is 3 meters. A quarter of it is 75 cm. It's long enough to ordinary PCB size. (The cap is directly connected to pwr/gnd planes.) This means that we can loosely define the largest usable board area capacitance as 1/8 wavelength radius of copper surrounding the IC power pin. Charges stored on the planes further than 1/8 wavelength away are not very usable due to the time delay. At 500MHz in FR4, 1/8 wavelength is 1.5 inches. Is such a board capacitor good enough for your IC? George, I beg for differentials. How did you jump from capacitors placed 1/4 wavelength away are bad to the largest usable board area capacitance as 1/8 wavelength radius? Can I use the same token to infer from caps placed one wavelength away are good to the largest usable board area capacitance is within 1/2 wavelength radius? And so, and so on. Regards, Barry Ma b...@anritsu.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Need a substitute part
Try a search in www.partminer.com that's a hope. Ralph Cameron EMC Consultant for Suppression of Consumer Electronic Equipment (After sale) - Original Message - From: Allan, James james_al...@milgo.com To: 'emc-pstc' emc-p...@majordomo.ieee.org Sent: Tuesday, May 16, 2000 1:19 PM Subject: Need a substitute part HELP! I am looking for an equivalent to a connector from Spectrum Control part number 93538-1. This is a shielded 8 position modular phone jack with a capacitive filter of 110 pf at 710VDC on each pin. It was formerly Amp part number 93538-1 before Spectrum Control bought the rights. Any one out there have an idea of who might make an equivalent? (Yeah - Right) Link to Spectrum catalog page here http://www.spectrumcontrol.com/sigconpdfs/jackconn.pdf Jim Allan Senior Compliance Engineer Milgo Solutions Inc. E-mail james_al...@milgo.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Re[2]: [SI-LIST] : Charge moving from decoupling capacitors
Equally important is that respect has to be paid to impedance matching ; other wise, energy is reflected from the load and this will degrade the risetime as well as cause some energy to be radiated. The dielectric material must be low loss so that you ensure the signal is conducted with minimum attenuation.and keeping the path length to the chip to a minimum keeps the undesired switching products very low. Ralph Cameron EMC Consultant for Suppression of Consumer Electronics (after Sale). - Original Message - From: Jim Bacher jim_bac...@mail.monarch.com To: Larry Miller ldmil...@nortelnetworks.com; EMC-PSTC emc-p...@ieee.org Sent: Friday, May 12, 2000 11:24 AM Subject: Re[2]: [SI-LIST] : Charge moving from decoupling capacitors Forwarded for Larry. Reply Separator Subject:Re: [SI-LIST] : Charge moving from decoupling capacitors Author: Larry Miller ldmil...@nortelnetworks.com Date: 5/12/00 7:37 AM Hi, Barry, Responses below: At 03:49 PM 5/11/00 -0700, Barry Ma wrote: Hi, As the speed of digital signals gets faster and faster, people begin being concerned with the distance for electric charge to move on power and ground planes of multilayer PCB during the signal rise time from a decoupling capacitor (cap) to a chip it serves. I would like to raise two questions. (1) The charge is moving in a metalic plane, not inside the dielectric between pwr and gnd planes. Please let me know why you have to use the propagation velocity in the dielectric, instead of that in the metal. Due to skin effect at anything above a few tens of kHz, the current flows mainly on the surface of the trace, so it has to interact with the dielectric in accordance with Maxwell's equations for electromagnetic waves. (2) The second question is regarding distance between the cap and the chip. Do we really have to limit the distance letting the charge have enough time to move from the cap to the chip during the rise time interval? I doubt it. No, you have to let the wave propagate (see below). Take the running water system for example. When we open, then close the water faucet within one second, does the water we've got in basin come from water tower (or water station, or reservoir)? No, it is the water that resides in the pipe. As a matter of fact, we have a very large pipe - pwr/gnd planes. Well, of cause you know, I did not mean we don't need water tower - the cap. .. The running water analogy breaks down here (at AC). Another analogy would be that the current is comprised of many successive collisions between billiard balls, not the motion of one single ball. Yet another analogy would be to look at the current as a game of Chinese checkers, where an individual electron can only move into a hole in the board vacated by another electron (if you overcome this you get superconduction!). As I recollect, the actual speed of an identifiable electron, assuming you could actually identify it, is on the order of a few meters/sec, though the electromagnetic wave caused by the transfer of energy between electrons travels at the speed of light in the medium. Larry Miller --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Ground potential differences....
Doug: Just to enhance your observation, at RF ( i.e. broadcast frequencies 520-1800 Khz) there is a pseudo resonant effect that places RF ground at different places in a building , home etc. The RF ground is dependant on the intereception of direct radiation and is related to how much wiring is exposed and the angle of exposure. It would make an interesting problem to model. In one case, a CD system on a second floor was completely disabled by RF common mode) and the only way to re establish a ground reference was tying the ground lead from the CD player to the bedprings. It may sound far fetched, but it worked. Sometimes plugging into a different AC outlet in the same room , cleared the problem. Ground potential difference can also occur when transformer insulation becomes leaky , mainly due to age. Cheers. Ralph Cameron EMC Consultant for Suppression of Consuemr Electronic Equipment (After Sale) - Original Message - From: Doug dmck...@gte.net To: emc-p...@majordomo.ieee.org Sent: Saturday, May 06, 2000 1:18 PM Subject: Re: Ground potential differences I'm going to stick my neck out here and say from two experiences with this topic, there's a couple of things to consider ... First, ideally, any potential difference between GROUNDS should be zero. If you had asked about NEUTRALS, I'd have to say - unknown. The physical connection is a function of the connection to the transformer by the electricians and imperfections in the transformer. Second, it's a function of what's sourcing the difference. I worked at a place where the outlets in one half of the lab were supplied by a different substation than the outlets at the other end of the lab. Without knowing the issue, we connected two different machines with a coax. Each machine eventually connected to different substations by way of differently sourced outlets. And we watched with amazement as the rubber jacket of the coax melted. All with a 15V difference. The electricians were notified and the problem was solved but a potential difference of some sort was still there. I don't think you'll ever get away from it. So, I guess what I'm saying is that you should not only consider the voltage difference, but the power involved. And that would be have to tested some other way. - Doug McKean Kelly Tsudama wrote: Hi gang! I have been asked to look into ground potential differences by one of the teams that I support. Can any of you provide any insight on how I can determine the maximum potential difference between different ground circuits within a building??? I've heard numbers ranging from 2V to 50V!!! Even with all the bonding requirements in the NEC, there must be some voltage differential between grounding points??? Thanks for any help you can provide. Kelly --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: E-Field Probe Question
That's a bit of a puzzler Robert. As I recall, Tektronix used to state ristetime in terms of that observed when passing through amplifiers with gaussian rolloff and it was Rt(ns)= Bandwidth(Mhz) / 350 Ralph Cameron - Original Message - From: Robert Macy m...@california.com To: Dan Kwok dk...@intetron.com; Ralph Cameron ral...@igs.net; EMC-PSTC Group emc-p...@majordomo.ieee.org Sent: Monday, January 24, 2000 8:54 PM Subject: Re: E-Field Probe Question At first that looked like what is asked for is the ability to pass signals with a bandwidth of 10Hz. Given what they're looking for, stating frequency would make it easier to understand. But isn't the risetime 1/2pi F?? Or, are they just saying that the readings pop out at least 10 times per second, with the ability to respond in one reading? - Robert - Ralph Cameron wrote: Tr usually ment risetime when referred to pulsed signals. In this case I think it refers to response time less than 10Hz. In other words you'll get a reading in less than the period of ten hertz at the frequency of measurement. Hi Ralph, Would that be more appropriately stated as 0.10 sec? Just curious. Regards, Dan Kwok -- = Daniel Kwok Vancouver, BC, Canada Intetron Consulting, Inc. Telephone 604.432.9874 Email dk...@intetron.com FREE EMC Tips @ our website http://www.intetron.com; = - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: E-Field Probe Question
Yes, Dan, you're correct. Ralph Cameron - Original Message - From: Dan Kwok dk...@intetron.com To: Ralph Cameron ral...@igs.net; EMC-PSTC Group emc-p...@majordomo.ieee.org Sent: Monday, January 24, 2000 6:50 PM Subject: Re: E-Field Probe Question Ralph Cameron wrote: Tr usually ment risetime when referred to pulsed signals. In this case I think it refers to response time less than 10Hz. In other words you'll get a reading in less than the period of ten hertz at the frequency of measurement. Hi Ralph, Would that be more appropriately stated as 0.10 sec? Just curious. Regards, Dan Kwok -- = Daniel Kwok Vancouver, BC, Canada Intetron Consulting, Inc. Telephone 604.432.9874 Email dk...@intetron.com FREE EMC Tips @ our website http://www.intetron.com; = - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: E-Field Probe Question
Tr usually ment risetime when referred to pulsed signals. In this case I think it refers to response time less than 10Hz. In other words you'll get a reading in less than the period of ten hertz at the frequency of measurement. Ralph Cameron EMC Consultant and Suppression of Consuemr Electronic Equipment (After Sale) - Original Message - From: Martin Rowe (TMW) m.r...@ieee.org To: emc-p...@ieee.org Sent: Monday, January 24, 2000 12:17 PM Subject: E-Field Probe Question I need clarification on a spec for an e-field probe. The spec is Tr less than 10 Hz. What is Tr? The probe is specified in SAE J1113/27 Electromagnetic Compatibility Measurements Procedure for Vehicle Components: Part 27:Immunity to Radiated Electromagnetic Fields-Reverberation Method. Thanks, /\ | Martin Rowe | / \ | Senior Technical Editor | /\ /\ | Test Measurement World | / \/ \/\ | voice 617-558-4426 |/\ /\ / \/ | fax 617-928-4426 | \/ \/ | e-mail m.r...@ieee.org | \ / | http://www.tmworld.com |\/ - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Surge Test Performance Criterion
It wasn't done derek because there is no requirement that is mandatory. My humble opinion says voluntary standards don't work as well as they should.. Sometimes it requires a resistor to limit the current going to the switch as it obviously rectifies some of the RF. In some cases a bypass capacitor is required also. on the hot lead to ground. Ralph - Original Message - From: Derek Walton l...@rols1.net To: Ralph Cameron ral...@igs.net Cc: carlos.perk...@eu.effem.com; Jim Hulbert hulbe...@pb.com; emc-p...@ieee.org Sent: Thursday, January 13, 2000 3:12 PM Subject: Re: Surge Test Performance Criterion Ralph, if all it takes is a resistor, I wonder why it wasn't done 99% of the population are stuck with a crap product The idea with CE was that this shouldn't happen! Derek. Ralph Cameron wrote: Derek: You want to locate one of those lights next to a transmitter that is used intermittently - the light sequences through LO-Medium-high then turns off only to come back on again when the transmitter is keyed. The AC switching device lacks immunity to RF but it may be easily cured with the addition of a single resistor. Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment. (After sale) - Original Message - From: Derek Walton l...@rols1.net To: carlos.perk...@eu.effem.com Cc: Jim Hulbert hulbe...@pb.com; emc-p...@ieee.org Sent: Thursday, January 13, 2000 8:57 AM Subject: Re: Surge Test Performance Criterion Sorry Carlos, I can't go along with this one. If I'm using my PC here in the USA midwest and a storm comes along I don't want my PC shutting itself off every few minutes Only been hit directly with two lightning strikes this last 2 years, but during a storm you can continuously heat squeaking as the modem is hit, I know the power is seeing voltage surges too. I'll have to put a Dranitz on the power just to see what kinds of voltage surges arrive The same applies to surges generated by motors etc. If every time a motor switches on and my equipment does something, well that would have to go back to the store. By the way, I don't expect to find in the small print all sorts of get out clauses once I buy something A controlled shut down is there to prevent loss of life, destruction of the device, or something as equally bad. By the way, I was back home ( Manchester, England ) last October and bought my Mum a light that turns on when you touch any metal part of it, it was CE marked. I have a similar light here in the USA, mine's not CE marked. BOTH turn on/off when there are voltage transients on the power line. Now you can wrangle all you want, but being woken up in the middle of the night because the light turned on when the dishwasher began it's Saver Seven ( low cost overnight electricity ) cycle, is not acceptable performance! If then manufacturer calls this acceptable performance, then perhaps I should call him/her in the middle of the night each time to confirm that opinion...;-) What products do you make again;-))) Derek. During surge carlos.perk...@eu.effem.com wrote: Jim, I agree with you, on the basis that in this case, a complete shut-down is a designed-in function of the product, and the standard says No degradation of performance or loss of function is allowed below a performance level specified by the manfucturer. You, as the manufacturer, are specifying this 'loss of function'. In my mind, all you have to do is make the end user aware that a shut-down will occur when a surge is detected, and you should be OK. Cheers, Carlos. Please respond to Jim Hulbert hulbe...@pb.com To: emc-p...@ieee.org cc: (bcc: Carlos A. Perkins/WIN/Effem) From: Jim Hulbert hulbe...@pb.com on 12/01/2000 20:08 Subject: Surge Test Performance Criterion A product has a switched mode power supply with a current sensing circuit that causes the supply to shut down when a surge pulse is applied to the AC mains in accordance with EN61000-4-5/IEC1000-4-5. After about 10 minutes, the supply can be turned back on and normal operation of the product can be resumed by the operator. Does this product conform to criterion B of the EN 50082-1 or EN 55024 standards? I believe it does because the sensing circuit is specifically designed to protect the product against this kind of voltage/current surge and the product operation is fully recoverable by the operator afterward. However, I would like to hear how others who do this testing would interpret this. Jim Hulbert Senior Engineer - EMC Pitney Bowes - This message is coming from the emc-pstc discussion list. To cancel your
Re: LVD Essential Requirement for Radiation Protection
Patrick: I think you might find this definitive paragraph from the Canadian Broadcaster's Manual on Non Ionizing Radiation pertintent to your query and which complements other comments received: Radiation, Ionizing and Non Ionizing ... the energy in an electromagnetic wave increases with frequency. Around the ultraviolet range ( about 2 million Mhz) the energy is sufficient to dislodge captive electrons, resulting in charged particles (ions) dashing about with energies sufficient to break down or change atoms or molecular structures. At this point the energy wave is classed as ionizing radiation. Humans endure continuos natural low level ionizing radiation and regulations control occupational exposure to some 2.5 millirems per hour for x-rays; the American and Canadian standards for ultraviolet are based on a maximum exposure of one milliwatt per square centimeter . Visible light and infrared are controlled as well, at ten milliwatts per sq. cm. Excessive radiation at any frequency can be injurious to health. Limits do vary from country to country and Canada's Safety Code 6 is a guidline recently revised where exposure to EM radiation can occur. It applies to the general population as well as workers in the field. Copies are availabel in pdf format if needed. Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment ( After Sale) . - Original Message - From: Patrick Lawler plaw...@west.net To: emc-p...@majordomo.ieee.org Sent: Thursday, January 13, 2000 11:49 AM Subject: Re: LVD Essential Requirement for Radiation Protection What does 'non-ioniozing emissions' cover? Is it in the category of personnel safety and low-frequency EMF, or does it encompass simple product emissions like those specified in CISPR 11? On Wed, 12 Jan 2000 11:33:02 -0500, wo...@sensormatic.com wrote: An interesting thing has happened to the LVD. Until now, the radiation essential requirement of the LVD has been interpreted as referring to ionizing radiation and there are harmonized standards addressing that requirement, for example, EN 60950. That interpretation has now changed. In a draft mandate to CENELEC, CEN and ETSI, the Commission is now interpreting the radiation essential requirement of the LVD to include non-ionizing emissions and that the limits for the general public are to be per the Council's EMF Recommendation. The standards bodies are mandated to produce basic and product standards that would apply to the LV and RTTE Directives. There are no worker limits promulgated at the EU level. Which leads me to my question. When would this new interpretation of the essential requirement take effect - now or the DOW of the associated standard? -- Patrick Lawler plaw...@west.net - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Surge Test Performance Criterion
Derek: You want to locate one of those lights next to a transmitter that is used intermittently - the light sequences through LO-Medium-high then turns off only to come back on again when the transmitter is keyed. The AC switching device lacks immunity to RF but it may be easily cured with the addition of a single resistor. Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment. (After sale) - Original Message - From: Derek Walton l...@rols1.net To: carlos.perk...@eu.effem.com Cc: Jim Hulbert hulbe...@pb.com; emc-p...@ieee.org Sent: Thursday, January 13, 2000 8:57 AM Subject: Re: Surge Test Performance Criterion Sorry Carlos, I can't go along with this one. If I'm using my PC here in the USA midwest and a storm comes along I don't want my PC shutting itself off every few minutes Only been hit directly with two lightning strikes this last 2 years, but during a storm you can continuously heat squeaking as the modem is hit, I know the power is seeing voltage surges too. I'll have to put a Dranitz on the power just to see what kinds of voltage surges arrive The same applies to surges generated by motors etc. If every time a motor switches on and my equipment does something, well that would have to go back to the store. By the way, I don't expect to find in the small print all sorts of get out clauses once I buy something A controlled shut down is there to prevent loss of life, destruction of the device, or something as equally bad. By the way, I was back home ( Manchester, England ) last October and bought my Mum a light that turns on when you touch any metal part of it, it was CE marked. I have a similar light here in the USA, mine's not CE marked. BOTH turn on/off when there are voltage transients on the power line. Now you can wrangle all you want, but being woken up in the middle of the night because the light turned on when the dishwasher began it's Saver Seven ( low cost overnight electricity ) cycle, is not acceptable performance! If then manufacturer calls this acceptable performance, then perhaps I should call him/her in the middle of the night each time to confirm that opinion...;-) What products do you make again;-))) Derek. During surge carlos.perk...@eu.effem.com wrote: Jim, I agree with you, on the basis that in this case, a complete shut-down is a designed-in function of the product, and the standard says No degradation of performance or loss of function is allowed below a performance level specified by the manfucturer. You, as the manufacturer, are specifying this 'loss of function'. In my mind, all you have to do is make the end user aware that a shut-down will occur when a surge is detected, and you should be OK. Cheers, Carlos. Please respond to Jim Hulbert hulbe...@pb.com To: emc-p...@ieee.org cc: (bcc: Carlos A. Perkins/WIN/Effem) From: Jim Hulbert hulbe...@pb.com on 12/01/2000 20:08 Subject: Surge Test Performance Criterion A product has a switched mode power supply with a current sensing circuit that causes the supply to shut down when a surge pulse is applied to the AC mains in accordance with EN61000-4-5/IEC1000-4-5. After about 10 minutes, the supply can be turned back on and normal operation of the product can be resumed by the operator. Does this product conform to criterion B of the EN 50082-1 or EN 55024 standards? I believe it does because the sensing circuit is specifically designed to protect the product against this kind of voltage/current surge and the product operation is fully recoverable by the operator afterward. However, I would like to hear how others who do this testing would interpret this. Jim Hulbert Senior Engineer - EMC Pitney Bowes - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord
Re: Radiation levels.
David: I would be very cautious about personal cell phones field intensity measurements . The proximity of the antenna is so close to the body (head) that some field intensity values I've heard about approach 200-500 V/.m. The power from such devices is very low but close proximity puts it in the near field and the jury still seems to be out debating what the actual values are. I know a company in this area is modeling the human head with the intention of re shaping the radiation pattern to offer more protection to the exposed body. Another area of concern is high powered airport surveillance radar. The fields generated derive from many megawatts of effective radiated power (erp). i.e. power multiplied by antenna gain. Industry Canada produced a paper called the Electromagnetic Compatibility Bulletin known as , EMCAB -1, and it ran into three issues. It was a survey conducted in 1983 and covered the subject of electromagnetic compatibility urging manufactureres to design immunity into their products because of the EM interaction due to proximity effects. It was well conceived and well researched and has a table of all the expected fields to be expected from users of the EM spectrum. It gave quite a bit of detail as to why EMC was desireable and those needs haven't changed much except there are more devices now and more EMC related problems . This is someowhat off the topic of this discussion group but EMC is embedded in any design where safety is of concern. The fields applied to each service are useful design criteria. The point made in the paper was that it is easier to design EMC into a product than try to fix it afterwards. If interested, I can either scan or copy EMCAB-2 for anyone's use. Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment. (After sale) - Original Message - From: David Monreal dmonr...@advancedshielding.com To: emc-p...@majordomo.ieee.org Sent: Wednesday, January 12, 2000 7:41 AM Subject: RE: Radiation levels. Dear answerers, thanks for your kind help. The real cases have been VERY useful. If you have more of them, please send the values to me. Thanks again. David - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Y3K
Roger, Most of this problem occurs from the Latin M= 1000 and the Greek K=1000 What came later just confused the issue- is this an example of a decision by committee(s) ? Ralph Cameron - Original Message - From: roger.vi...@wwgsolutions.com To: emc-p...@majordomo.ieee.org Sent: Tuesday, January 11, 2000 5:38 AM Subject: RE: Y3K Thanks to all who made their comments following my complaint about the misuse of K for 1000. Maybe a final word about this problem! The IEC (even more pedantic!) are attempting to fix this by creating a new set of units for binary multiples (Amendment 2 to IEC International Standard IEC 60027-2: Letter symbols to be used in electrical technology - Part 2: Telecommunications and electronics.): Ki (kibi) = 2E10 (1024) Mi (mebi)= 2E20 (1 048 576) Gi (gibi) = 2E30 (1 073 741 824) etc. For details (and to check this is not some early April 1 joke) see the SI prefix description on the US National Institute of Standards and Technology website at: http://physics.nist.gov/cuu/Units/prefixes.html (confirms that x1000 is small k!) and then the binary prefix description at: http://physics.nist.gov/cuu/Units/binary.html I don?t see the whole IT industry changing its usage to this new set of prefixes ! Roger Gary McInturff gmcintu...@telect.com on 06/01/2000 22:49:38 Please respond to Gary McInturff gmcintu...@telect.com To: 'Egon H. Varju' e...@varju.bc.ca, EMC-PSTC emc-p...@ieee.org cc:(bcc: Roger Viles/PLY/Global) Subject: RE: Y3K Oh my last birthday my children wanted to know if I was really, really sad when the Dinosaur's all died - heavy sigh! Anyway - M is for Mega or 1,000,000 and K for Kilo or 1,000 But I'm sorta betting you're getting tired of hearing that. Gary -Original Message- From: Egon H. Varju [mailto:e...@varju.bc.ca] Sent: Thursday, January 06, 2000 9:17 AM To: EMC-PSTC Subject: Re: Y3K Roger, way back in the days of the caveman, 1M ohms = 1000 ohms. Guess going metric changed everything. Strange ... During my dinosaur hunting days, 1M ohm used to be = 1 000 000 ohms. Maybe we grew up in parallel universes ... Egon :-) __ Egon H. Varju, PEng E.H. Varju Associates Ltd. North Vancouver, Canada Tel: 1 604 985 5710 HAVE MODEM Fax: 1 604 273 5815 WILL TRAVEL E-mail: e...@varju.bc.ca eva...@compuserve.com egon.va...@csa-international.org __ - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Radiation levels.
David: The field strength at any given point remote from the antenna system can be quite variable and depends on power output, antenna pattern, height of antenna above ground (TV) and whether you're in the near or far field. I've seen levels of 200V/m 200 ft from a 50Kw broadcast array and the Canadian Association of Broadcasters has a software program written in basic to estimate the field from a TV/FM antenna. Canadian Safety Code 6 from Health Canada provides formulae for such estimates. Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment (After sale) - Original Message - From: David Monreal To: emc-p...@majordomo.ieee.org Sent: Tuesday, January 11, 2000 5:14 AM Subject: Radiation levels. Hi all! Could anyone tell me the radiation levels (V/m) generated by broadcast antennae? (Radio and TV). I also need the radiation levels for any other emmitig devices, machinery, GSM antennae, etc. The more information the better. Thanks a lot :-) David - The V/m guy
Re: Y3K
Hans and Dan: You're overlooking the fact that by definition in modern computers a byte = 8 bits so when they say 100Mb drive they mean exactly that, 100 megabytes = 800 megabits capacity. ( if you ignore the parity bit which is seldom transmitted or recorded.). . A 56K modem downloads files at 5Kbytes/sec = approx. 40kbps with the usual line loading. Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment (After Sale) - Original Message - From: Dan Kwok dk...@intetron.com To: EMC-PSTC Group emc-p...@majordomo.ieee.org Sent: Friday, January 07, 2000 6:01 PM Subject: Y3K Hello everyone; Of the more recent units that have been a major source of confusion for many Internet users, myself included, were the units for download speeds: K/sec versus kbps. It made a lot of users wonder why their 56K modem only downloaded files at 5K/sec instead of say- 40 kbps. It turns out the 5K/sec as indicated on the browser, is actually based on an 8-bit word length so 5K/sec actually represented 5x8 or 40 kilo-bits-per-second. That is a lot closer to 56 kbps even though typical connection speed is limited to the range of 40-50 kbps for most ISPs. -- === Dan Kwok Vancouver, BC, Canada Intetron Consulting, Inc.Telephone 604.432.9874 Email dk...@intetron.com *FREE* EMC Tips @ our website http://www.intetron.com === - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Y3K
Not so strange these circuits from 1926- figs 34 and 34 are examples. Parallel , Yes. Ralph - Original Message - From: Egon H. Varju e...@varju.bc.ca To: EMC-PSTC emc-p...@ieee.org Sent: Thursday, January 06, 2000 12:17 PM Subject: Re: Y3K Roger, way back in the days of the caveman, 1M ohms = 1000 ohms. Guess going metric changed everything. Strange ... During my dinosaur hunting days, 1M ohm used to be = 1 000 000 ohms. Maybe we grew up in parallel universes ... Egon :-) __ Egon H. Varju, PEng E.H. Varju Associates Ltd. North Vancouver, Canada Tel: 1 604 985 5710 HAVE MODEM Fax: 1 604 273 5815 WILL TRAVEL E-mail: e...@varju.bc.ca eva...@compuserve.com egon.va...@csa-international.org __ - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). attachment: audio.jpg
Re: Y3K
Roger, way back in the days of the caveman, 1M ohms = 1000 ohms. Guess going metric changed everything. Ralph Cameron - Original Message - From: roger.vi...@wwgsolutions.com To: Jon Griver jgri...@i-spec.com Cc: emc-p...@majordomo.ieee.org Sent: Wednesday, January 05, 2000 12:09 PM Subject: RE: Y3K Personally I'm still waiting for another 48 years until the Y2K bug bites! Aside from its real meaning as degrees Kelvin, capital K was first used by the computer guys as a de-facto agreed unit for binary thousand (1024) as in Kbytes. Sloppiness by the financial community led to its use there for thousands of dollars, etc. and ignorance by the media has resulted in its general use. Together with the shorthand loved by Americans this has led to Y2K! However of course the official unit for 1000 has always been lower case k, as in km, kHz, etc. Happy Y2k ! (I won't see Y2K!) Roger - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Common Mode or Differential Mode
Bob, if you are just trying to identify the type you could connect a boradband scope with hig impedance input from each line to ground, assuming the conductors are carrying AC. The voltages from each side to ground should be nearly identical if the common mode currents are close to the same value, i.e. equal volatges. If there is much difference, you can be sure DM currents are flowing. regards, Ralph Cameron Consultant in EMC and Suppression of consumer electronic equipment (After sale) - Original Message - From: rehel...@mmm.com To: emc-p...@majordomo.ieee.org Sent: Tuesday, January 04, 2000 5:20 AM Subject: Common Mode or Differential Mode Are there rules of thumb or a quick and dirty means of determining whether conducted emission noise (or radiated) is common mode or differential mode? Thanks and have a great new year. Bob Heller 3M Company - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: CE Marking On Shipping Cartons
I will only buy computer products that show the CE label. Often this is marked on the shipping container so it makes it easier to identify . Proudcts made to CE specs are superior from a radiated emissions standpoint and much less susceptible to conducted emissions. In my opinion, it is a marketing feature yet to be exploited. Ralph Cameron Consultant in EMC and Suppresion of Consumer electronic equipment (After Sale) - Original Message - From: roger.vi...@wwgsolutions.com To: Jacowleff, Bill bjacowl...@vdo.com Cc: Emc-Pstc (E-mail) emc-p...@ieee.org Sent: Tuesday, January 04, 2000 4:55 AM Subject: Re: CE Marking On Shipping Cartons The general rule requires that CE marking must be affixed to the product or its data plate. However where this is not possible or not warranted on account of the nature of the product, it must be afixed to the packaging, if any, and to the accompanying documents, where the directive concerned provides for such documents. However note that the recent RTTE Directive does appear to mandate marking the packaging: CE marking must be affixed to the product or its data plate. Additionally it must be afixed to the packaging, if any, and to the accompanying documents. I guess this is intended to ensure that any mark indicating restrictions on (countries of) use is visible from the outside. Roger - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Servicing and repairs
Brian: As a comment I would say that the liability to meet EU approval ends when the product is sold and ownership is transferred. That's the way it happens with consumer goods in Canada, in spite of the fact there is CSA approval required on the original product. Compliments of the Season Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment (After Sale). - Original Message - From: Brian Harlowe bharl...@vgscientific.com To: emc-p...@ieee.org Sent: Tuesday, December 21, 1999 9:04 AM Subject: Servicing and repairs Traditionally my company has encouraged it's users to carry out a limited amount of servicing and repair on our Electronic units. Under the EU Safety legislation I know this is now a No No. I am a little bit of a lone voice crying in the wilderness as far as our management is concerned. Can any one out there quote me any instances or cases that I can use to drive home the point with our management A happy Christmas to you fellow compliance people and if we survive the Y2K business. Good luck in the new century and may this newsgroup continue to prosper Best Regards Brian Harlowe * opinions expressed here are personal and in no way reflect the position of VG Scientific - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Magnetic field monitors
Health Canada, under Safety Code 6 specifies magnetic field strength in A/m . Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment (After Sale) - Original Message - From: Mike Hopkins mhopk...@keytek.com To: 'Rich Nute' ri...@sdd.hp.com Cc: 'IEEE' emc-p...@ieee.org Sent: Friday, December 17, 1999 6:42 AM Subject: RE: Magnetic field monitors IEC 1000-4-8 require testing products in a square loop with magentic field strengths expressed in Amps/meter; hence, customers want measurement/monitoring equipment that reads in Amps/meter. Page 17 of 1000-4-8 states The magnetic field strength is expressed in A/m; 1 A/m corresponds to a free space induction of 1.26uT. Mike Hopkins mhopk...@keytek.com -Original Message- From: Rich Nute [SMTP:ri...@sdd.hp.com] Sent: Thursday, December 16, 1999 6:02 PM To: mhopk...@keytek.com Cc: emc-p...@ieee.org Subject: Re: Magnetic field monitors Hmmm. Let's see: Magnetic field strength is measured in: amperes/meter oerstads Magnetic flux density is measured in: tesla gauss As near as I can tell, there is no conversion from one to the other. This would imply they are separate phenomenon. I'm not in the EMC field, but I'm curious as to regulatory requirements and what interferences such emissions would cause. (I'm presuming both are regulated.) Best regards, Rich - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Piezo lighters
You can measure that with a 40KV probe and a digital storage scope set for single shot event. i.e the scope triggers from the event. Probe loading should be as low as possible ( hi Z probe). Ralph Cameron - Original Message - From: carlos.perk...@eu.effem.com To: emc-p...@ieee.org Sent: Wednesday, December 15, 1999 11:24 PM Subject: Piezo lighters Dear All, Does anyone out there know what the peak voltage of a handheld piezo gas lighter is? Or how to measure it? Any tips would be very welcome. Many thanks, Carlos. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: RTTE Directive EMF Limits
Richard: The Canadian version of your FCC limts is called Safety Code 6 and has recetnly been revised by Health Canada. it doesn't permit computer simulations but of course in the lab you can do anything. Ralph Cameron Consultant in EMC and Suppression of Consumer Electronic Euipment (After sale) - Original Message - From: wo...@sensormatic.com To: emc-p...@majordomo.ieee.org Sent: Wednesday, December 15, 1999 5:46 AM Subject: RTTE Directive EMF Limits The RTTE Directive includes an essential requirement for health and safety which is interpreted by the Commission as human exposure to EMF. I would like to hear from anyone that has equipment operating at less than 100 kHz and plans on demonstrating compliance to the basic limits. This is what my company plans to do using computer simulation. Richard Woods - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Open Frame EMI Filters
Doug: It would seem logical that the shield will guarantee a high degree of immunity to local radiated fields. If the filter is a commerical one its specs are probably dependent on the shield being in situ. Even though it may meet the EMC test requirement, there is an added degree of safety i.e. equipment malfunction) with the filter in place. If there is line voltage appearing on any of the components and they are in areas used by service people then the question of electrical safety is addressed by having a shield. This is only my opinion. Ralph Cameron EMC Consultant and Suppression of Consumer Electronics (After Sale) - Original Message - From: POWELL, DOUG doug.pow...@aei.com To: emc-p...@majordomo.ieee.org; Treg Listserv (E-mail) t...@world.std.com Sent: Wednesday, December 08, 1999 2:19 PM Subject: RE: Open Frame EMI Filters Hello once again, I have already received a number of replies to my query indicating that the metallic enclosure is required for low inductance coupling to the components or to prevent radiation between circuits within the product. This is not my question. Please remember that one of the criteria that I described for the open frame is the passing all applicable EMC tests. This means that the open-frame design that I propose meets both radiated and conducted emissions levels, without the metallic box. My questions deals more with why is the enclosure required if product passes the tests without it. In the past I have designed a few products with a simple PCB for emissions control. I compensated for the internal re-radiation problem. Recently I heard of a commercial EMI Filter company that says the enclosure is required and that the encapsulant is a requirement. I disagree. -doug === Douglas E. Powell Regulatory Compliance Engineer Advanced Energy Industries, Inc. 1625 Sharp Point Dr. Fort Collins, Colorado 80525 USA m/s: 2018 --- 970-407-6410 (phone) 970-407-5410 (e-fax) 800-446-9167 (toll-free) mailto:doug.pow...@aei.com http://www.advanced-energy.com === Hello group, For years I have used off-the-shelf and custom EMI filters with a fully enclosed metal canister. Why is this enclosure required? Are there specific provisions in the standards? My idea is to build up the filter circuit on a printed circuit board and make it an integral part of the power supply. I am currently looking at EN133200 which has certain seal tests but after reviewing these, they all appear to be related to climatic or environmental conditions. If the product passes these tests without the enclosure it would seem that the product has passed, period. Alternatively I have considered removing the nomenclature EMI filter and simply call it an input module, then evaluate it as a part of the overall system. If it passes the EMC and Product Safety requirements, can I call the job complete? Any thoughts? === Douglas E. Powell Regulatory Compliance Engineer Advanced Energy Industries, Inc. 1625 Sharp Point Dr. Fort Collins, Colorado 80525 USA m/s: 2018 --- 970-407-6410 (phone) 970-407-5410 (e-fax) 800-446-9167 (toll-free) mailto:doug.pow...@aei.com mailto:doug.pow...@aei.com http://www.advanced-energy.com http://www.advanced-energy.com === - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list
Re: warning label overkill?
Hi Ron: In the interest of safety, why place the onus on the consumer when he/she had nothing to do with the design? Ralph Cameron - Original Message - From: ron_du...@agilent.com To: emc-p...@majordomo.ieee.org; sobe...@fdanews.com Sent: Friday, December 03, 1999 6:40 AM Subject: RE: warning label overkill? I agree. I question the warning on champagne bottles. I mean anybody that reaches legal drinking age knows a champagne cork can become a projectile. This is a prime example of shifting the responsibility from the responsible person to the manufacturer. Ron Duffy Product Safety Engineer Aiglent Technologies -Original Message- From: sobe...@fdanews.com [mailto:sobe...@fdanews.com] Sent: Thursday, 02 December, 1999 14:14 To: emc-p...@majordomo.ieee.org Subject: FW: warning label overkill? Serious question even though this involves a non-electrical product: at what point do warning labels undermine themselves? I was surprised to find this warning label on a 20 oz bottle of Dr. Pepper. It seems to be unique to that brand -- Coke, Pepsi and whatnot don't seem to carry it. ! WARNING (exclamation point is inside a triangle) CONTENTS UNDER PRESSURE. CAP MAY BLOW OFF CAUSING EYE OR OTHER SERIOUS INJURY. POINT AWAY FROM FACE AND PEOPLE, ESPECIALLY WHILE OPENING. It didn't seem to be any more carbonated than the Cokes I usually buy. I can see the point of such labels on Champaign with the corks that often become projectiles. But the physics of a screw-off soda bottle cap just doesn't seem to have the same ballistic potential. (I know, I know, the GC made them do it. But still.) -- Sean Oberle Vice President of New Products Washington Business Information, Inc. 1117 N 19th St, Ste 200, Arlington, VA 22209 Voice: 703/247-3429; Fax: 703/247-3421 - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Ferrites can increase emissions?
The purpose of a common mode choke whether it be of ferrite or powdered iron is to isolate the connecting conductors from the rest of the mainboard or chassis. If the toridal core is correctly placed as close to the source of the emissions i.e. the PCB, the conductors which carry the emitted noise are effectively isolated from high frequency noise currents to flow in common mode. The attenutaion will vary acording to the efficiency of the material selected and a permeability of a nominal 850 is useful over the range 3-40 Mhz. Some of the telphone companies use common mode chokes to attempt to suppress induced RF energy on phone lines and sometimes it works. They alsmot always specify placement of the in line encapsulated choke (ATT Z1000) at the wall socket. The amount of connecting cable from the phone to the wall socket is a good antenna too so picks up RF and bypasses any effect of the common mode choke. Although the problem is removing the condcuted current before it becomes a problem , the same principle applies to emitted noise. In some cases of suppressing consumer equipment there is a dramatic increase in sensitvity to conducted currents at different frequencies( usually higher) and this requires that the ground loop provided by the power cord be isolated from the device. Inevitably this has cured the problem. Be aware that any cabling connected to a device can radiate as well as conduct undesireable energy into the device. Ferrites provide a simple, non intrusive, inexpensive solution to such problems. You will see them on all the better quality computer monitors and laptops. Ralph Cameron Independant EMC Consultant and suppresion of consumer electronics (After sale) - Original Message - From: Douglas C. Smith d...@dsmith.org To: emc-pstc emc-p...@majordomo.ieee.org Sent: Wednesday, December 01, 1999 9:46 PM Subject: Ferrites can increase emissions? Hi All, I have noticed (like I expect many of you) that sometimes adding a ferrite on a cable to suppress common mode current caused emissions actually increases emissions at some frequencies. After thinking about this and trying an experiment to confirm one mechanism, I wrote up an article describing that mechanism. I have posted the article on my website (emcesd.com or www.dsmith.org) as the Technical Tidbit article for December. For the case shown there, a ferrite added at the OPPOSITE end of the cable from EUT2 would actually reduce emissions from EUT2 at frequency F2. Whereas if added at EUT2, emissions from EUT2 go down but go up from EUT1. Sort of an unusual case. Granted this is a special case, but the result is interesting and suggests lots of other possible configurations with strange results. Doug -- --- ___ _ Doug Smith \ / ) P.O. Box 1457 = Los Gatos, CA 95031-1457 _ / \ / \ _ TEL/FAX: 408-356-4186/358-3799 / /\ \ ] / /\ \ Mobile: 408-858-4528 | q-( ) | o |Email: d...@dsmith.org \ _ /]\ _ / Website: http://www.dsmith.org --- - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Ferrites can increase emissions?
Hi Doug: The term ground loop is misleading I agree. I meant to say coupling and by placing the ferrite remotely from the source of the emissions only serves to end load the conductors which will change the resonant length. In the case of placing the toroidal device on the power cord, right at the point of entry to the PCB, chassis, cabinet etc. the coupling loop as opposed to ground loop is generally broken and the harmful effects( device malfunction) disappear. I guess the point I'm trying to make is why defeat the purpose of a suppression device by placing it on conductors remotely from the source of the emissions? Ralph - Original Message - From: Douglas C. Smith d...@dsmith.org To: Ralph Cameron ral...@igs.net Cc: emc-pstc emc-p...@majordomo.ieee.org Sent: Thursday, December 02, 1999 8:43 AM Subject: Re: Ferrites can increase emissions? Hi Ralph and all, Please define ground loop in your reply below. Normally, the term ground loop only has meaning at low frequencies (60 Hz and DC). At high frequencies an infinite number of loops exist and they do not require a conductor to complete them. You need to define exactly the effect for the particular case below. The special case in my article goes a level deeper than your discussion to show that ferrites at one end of a cable can either increase or decrease emissions from equipment at the opposite end by either causing an impedance match or mismatch. No ground loops needed to explain this phenomenon. Doug Ralph Cameron wrote: The purpose of a common mode choke whether it be of ferrite or powdered iron is to isolate the connecting conductors from the rest of the mainboard or chassis. If the toridal core is correctly placed as close to the source of the emissions i.e. the PCB, the conductors which carry the emitted noise are effectively isolated from high frequency noise currents to flow in common mode. The attenutaion will vary acording to the efficiency of the material selected and a permeability of a nominal 850 is useful over the range 3-40 Mhz. Some of the telphone companies use common mode chokes to attempt to suppress induced RF energy on phone lines and sometimes it works. They alsmot always specify placement of the in line encapsulated choke (ATT Z1000) at the wall socket. The amount of connecting cable from the phone to the wall socket is a good antenna too so picks up RF and bypasses any effect of the common mode choke. Although the problem is removing the condcuted current before it becomes a problem , the same principle applies to emitted noise. In some cases of suppressing consumer equipment there is a dramatic increase in sensitvity to conducted currents at different frequencies( usually higher) and this requires that the ground loop provided by the power cord be isolated from the device. Inevitably this has cured the problem. Be aware that any cabling connected to a device can radiate as well as conduct undesireable energy into the device. Ferrites provide a simple, non intrusive, inexpensive solution to such problems. You will see them on all the better quality computer monitors and laptops. Ralph Cameron Independant EMC Consultant and suppresion of consumer electronics (After sale) - Original Message - From: Douglas C. Smith d...@dsmith.org To: emc-pstc emc-p...@majordomo.ieee.org Sent: Wednesday, December 01, 1999 9:46 PM Subject: Ferrites can increase emissions? Hi All, I have noticed (like I expect many of you) that sometimes adding a ferrite on a cable to suppress common mode current caused emissions actually increases emissions at some frequencies. After thinking about this and trying an experiment to confirm one mechanism, I wrote up an article describing that mechanism. I have posted the article on my website (emcesd.com or www.dsmith.org) as the Technical Tidbit article for December. For the case shown there, a ferrite added at the OPPOSITE end of the cable from EUT2 would actually reduce emissions from EUT2 at frequency F2. Whereas if added at EUT2, emissions from EUT2 go down but go up from EUT1. Sort of an unusual case. Granted this is a special case, but the result is interesting and suggests lots of other possible configurations with strange results. Doug -- --- ___ _ Doug Smith \ / ) P.O. Box 1457 = Los Gatos, CA 95031-1457 _ / \ / \ _ TEL/FAX: 408-356-4186/358-3799 / /\ \ ] / /\ \ Mobile: 408-858-4528 | q-( ) | o |Email: d...@dsmith.org \ _ /]\ _ / Website: http://www.dsmith.org --- - This message is coming from the emc-pstc discussion list
Re: Ferrites can increase emissions?
Hi Doug: I would agree with you technically and your intent. Ralph - Original Message - From: Doug Smith dsm...@corp.auspex.com To: Ralph Cameron ral...@igs.net; d...@dsmith.org Cc: emc-pstc emc-p...@majordomo.ieee.org Sent: Thursday, December 02, 1999 2:35 PM Subject: Re: Ferrites can increase emissions? Hi Ralph, I don't advocate placing the ferrite on the far end of cords. My example is meant to be instructive of the kind of mechanisms at work here and take some of the magic out of using ferrites. I would be interested in hearing from others in this group of unusual experiences with ferrites or details of other examples that yield unexpected results. This kind of discussion between fire fighting episodes on the job is the best part of EMC to me. Doug At 12:09 PM 12/2/99 -0800, Ralph Cameron wrote: Hi Doug: The term ground loop is misleading I agree. I meant to say coupling and by placing the ferrite remotely from the source of the emissions only serves to end load the conductors which will change the resonant length. In the case of placing the toroidal device on the power cord, right at the point of entry to the PCB, chassis, cabinet etc. the coupling loop as opposed to ground loop is generally broken and the harmful ffects( device malfunction) disappear. I guess the point I'm trying to make is why defeat the purpose of a suppression device by placing it on conductors remotely from the source of the emissions? Ralph - Original Message - From: Douglas C. Smith d...@dsmith.org To: Ralph Cameron ral...@igs.net Cc: emc-pstc emc-p...@majordomo.ieee.org Sent: Thursday, December 02, 1999 8:43 AM Subject: Re: Ferrites can increase emissions? Hi Ralph and all, Please define ground loop in your reply below. Normally, the term ground loop only has meaning at low frequencies (60 Hz and DC). At high frequencies an infinite number of loops exist and they do not require a conductor to complete them. You need to define exactly the effect for the particular case below. The special case in my article goes a level deeper than your discussion to show that ferrites at one end of a cable can either increase or decrease emissions from equipment at the opposite end by either causing an impedance match or mismatch. No ground loops needed to explain this phenomenon. Doug Ralph Cameron wrote: The purpose of a common mode choke whether it be of ferrite or powdered iron is to isolate the connecting conductors from the rest of the mainboard or chassis. If the toridal core is correctly placed as close to the source of the emissions i.e. the PCB, the conductors which carry the emitted noise are effectively isolated from high frequency noise currents to flow in common mode. The attenutaion will vary acording to the efficiency of the material selected and a permeability of a nominal 850 is useful over the range 3-40 Mhz. Some of the telphone companies use common mode chokes to attempt to suppress induced RF energy on phone lines and sometimes it works. They alsmot always specify placement of the in line encapsulated choke (ATT Z1000) at the wall socket. The amount of connecting cable from the phone to the wall socket is a good antenna too so picks up RF and bypasses any effect of the common mode choke. Although the problem is removing the condcuted current before it becomes a problem , the same principle applies to emitted noise. In some cases of suppressing consumer equipment there is a dramatic increase in sensitvity to conducted currents at different frequencies( usually higher) and this requires that the ground loop provided by the power cord be isolated from the device. Inevitably this has cured the problem. Be aware that any cabling connected to a device can radiate as well as conduct undesireable energy into the device. Ferrites provide a simple, non intrusive, inexpensive solution to such problems. You will see them on all the better quality computer monitors and laptops. Ralph Cameron Independant EMC Consultant and suppresion of consumer electronics (After sale) - Original Message - From: Douglas C. Smith d...@dsmith.org To: emc-pstc emc-p...@majordomo.ieee.org Sent: Wednesday, December 01, 1999 9:46 PM Subject: Ferrites can increase emissions? Hi All, I have noticed (like I expect many of you) that sometimes adding a ferrite on a cable to suppress common mode current caused emissions actually increases emissions at some frequencies. After thinking about this and trying an experiment to confirm one mechanism, I wrote up an article describing that mechanism. I have posted the article on my website (emcesd.com or www.dsmith.org) as the Technical Tidbit article for December. For the case shown there, a ferrite added at the OPPOSITE end
Re: Copy of: D of C - Who Signs?
Marin: Barring non compliant products from entry soon makes its point rather than trying to untangle the legal liability in such rare cases. Ralph Cameron Independant Consulting and EMC suppression in consumer electronics (after sale) - Original Message - From: Martin Green martin.gr...@iti.co.uk To: 'Allan G. Carr' al...@acarr.demon.co.uk Cc: 'Price, Ed' ed.pr...@cubic.com; emc-p...@ieee.org Sent: Thursday, November 25, 1999 6:05 AM Subject: RE: Copy of: D of C - Who Signs? Alan, As far as the quotation is concerned, I would refer you to the words in Reg. 40(2)(c), Erg 57(2)(c), Erg 70(2)(c) for clauses detailing who signs the DoC. Under the UK regulations it will, as I said in my email, be signed by or on behalf of the manufacturer or his authorised representative and identify that signatory As far as going to court is concerned, I too thought that action would be taken against the responsible person, but when I discussed this with both the DTI and some lawyers they said that as the offence would be placing on the market a product that did not meet the protection requirements - or similar words, and it would be a charge raised in a UK court, then it is the person selling it that is charged. Apparently, there is no cross border joint jurisdiction in the EU for CE marking offences. I understand that the UK authorities would inform the EU commission and they in turn would inform the authorities in Belgium. The Belgium authorities may then choose to investigate the offence to see if an offence had been committed in Belgium, under Belgium law. However, there is no doubt that the UK courts could not take action against a citizen in Belgium for this type of offence. Whether the Belgium authorities would be able to charge a Belgium citizen with an offence committed in the UK is open the question. It is like being charged for speeding in Germany and having a UK court hear the case. It does not work. As many will know to their cost (including me!), if you commit a motoring offence in Germany then you can pay a fine either on the spot or in court. Usually it on the spot - even if you are British! The UK courts do not hear motoring offences committed in Germany. Regards Martin -Original Message- From: Allan G. Carr [SMTP:e...@acarr.demon.co.uk] Sent: 25 November 1999 13:43 To: Martin Green Cc: 'Price, Ed'; 'emc-p...@ieee.org' Subject: Re: Copy of: D of C - Who Signs? Martin Thanks for the comprehensive reply to my post. I have the following comments:- The UK EMC regulations do not say the DoC is signed by the responsible person. They say the DoC must be signed by or on behalf of the manufacturer or his authorised representative and identify that signatory. Sorry to be pedantic but the UK Statutory Instrument 1992 No.2372 does not contain the above quote. This quote is from EC EMC Guidelines which therefore clarify the issue. The question always arises as to who ends up in court. As an example, if the DoC is signed in the USA, for a product made in Mexico, being sold by distributors in 10 of the member states in the EU, with the authorised rep in Belgium acting as the responsible person and there is a court case for infringement of the UK EMC regulations, who ends up in court? The action is taken in UK by the Trading Standards Officers against the person placing the product on the market in the UK. The answer is the distributor. The UK has no jurisdiction over the authorised rep in Belgium or the manufacturer outside the EU. UK Trading Standards tell me that in the above example the prosecution would be handed over to the EC country of residence of the responsible person who keeps the documentation - in this case Belgium. However the UK distributor could be in the firing line if UK Trading Standards were not happy with the result. Thanks again for your excellent response Allan In message E17783957970D21193D40080AD1CA3E20526C5@SERVER, Martin Green martin.gr...@iti.co.uk writes It is always interesting to read the legal interpretation of these documents. I now understand why lawyers make so much money. If you have the staying power you might find this or interest/value, otherwise hit the delete button! The interpretation below is incorrect. The UK EMC regulations do not say the DoC is signed by the responsible person. They say the DoC must be signed by or on behalf of the manufacturer or his authorised representative and identify that signatory. They also say the that DoC must give the name and address of the responsible person and where that person is not the manufacturer, of the manufacturer. For those who read this stuff and are not used to the arcane legal words inside UK Statutory Instruments this is often difficult to understand. The problem
Re: Article to UL
I woudn't take the Washington Post articel seriously but unfortunately in the struggle for the media to retain readership they act as interpreters of things they don't fully understand and in the course of publishing spread technical inaccuracies. The article is only an opinion, albeit one sided. I would agree with Peter that not juch is to be gained by negative bashing. Manufacturers should voluntarily ascribe to saftey as an ethical and moral obligation and promote the profession of responsible engineering. The same should apply to EMC immunity in products. I'd like to see the Washington Post write about that. I could help them. Keep up the objective comments, they lead to progress. Ralph Cameron Independant EMC Consulting for suppression of consumer products lacking EMC. (After sale). - Original Message - From: peterh...@aol.com To: emc-p...@majordomo.ieee.org Sent: Wednesday, November 24, 1999 8:08 PM Subject: Article to UL Hello group, It seems to me that the article in Washington Post, was written by someone who really had not done their homework. It sounded as the article was criticizing UL for not doing proper testing or not being able to write their standards adequately. Like most of the people in the group, I am certainly not a fan of UL for various reasons that are outside the scope of this particular subject, but one has to remember that almost majority of the standards are written with manufacturers directly involved during the generation of the standard. Obviously those of us who are being represented in various standard committee we who are responsible for writing the standard, try to influence the standard as much as we can in our industry favor and test houses such as UL, CSA , BSI, more or less go along with it. As for testing is concerned, all UL engineers as well as their counterparts in other test houses only test the product to the clauses of the standard and they are not allowed to go any further. On top of that, the way that any of these standard are written it is widely open to interpretation so we as test engineers always try to argue with the test house engineer to try to avoid any failure. Another point to bear in mind is that the test house engineers are only human like the rest of us and can make mistake or even overlook at some points. Last but not least, most of us have seen a certified product been slightly modified/altered by someone in our company for an unknown reason and still bears the safety mark without even informing any of the test houses concerned . So I believe we should look at the root casue of the problem and try to improve the situation by (a) be honest with the test houses during testing. (b) by trying to encourage our designers to make the product almost fool proof. © do addition in-house testing that exceeds the requirements of the standard (d) by being a truly responsible manufacturer. Thanks Peter - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Conducted Emissions for PS output
Derek The most common method I've found effective - even after sale- is the use of a toroidal ferrite core , large enough to take 8-9 turns of the power cord, mounted as close to the supply as possible. There is 15-20 dB decoupling to common mode noise provided by this method and I've used it hundreds of times. It also prevents ingress of RF. Ralph Cameron Independent EMC Consultant - Original Message - From: Derek Walton l...@rols1.net To: EMC Discussion Group emc-p...@ieee.org Sent: Tuesday, November 16, 1999 6:33 PM Subject: Conducted Emissions for PS output HI, would anyone like to suggest a specification for controlling conducted emissions from the output of a power supply or battery charger. The market place is either the USA or Europe. Thanks, Derek. -- Derek Walton Owner L. F. Research EMC Design and Test Facility 12790 Route 76, Poplar Grove, IL 61065. www.lfresearch.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
magnetic shielding
Mu metal with a very high permeability has always been used for shielding CRTs from the effects of stray magnetic shields, essentially creating a very low reluctance path. it is still used as far as I know. Ralph Cameron