RE: RTTE Directive
Courtland, For equipment covered by harmonized standards you are correct, no Notified or Conformity Assessment Body involvement is needed. This is the situation that most terminal equipment manufacturers find themselves in currently. On the other hand, there are a number of RF standards that have not yet been harmonized and there the involvement of a CAB or NB is necessary. I hope that this is helpful Best Regards, Barbara ___ Barbara L. Judge Vice President Compliance Certification Services Designated TCB and CAB 561F Monterey Road Morgan Hill, CA 95037 408-463-0885 ext.104 Fax: 408-463-0888 e-mail: bju...@ccsemc.com http://www.ccsemc.com -Original Message- From: Courtland Thomas [mailto:ctho...@patton.com] Sent: Thursday, June 21, 2001 1:09 PM To: emcpost Subject: RTTE Directive Hello group, After reading through the RTTE Directive for the fifth or sixth time, I am still not clear on the use of the notified/competent body and European representative. It seems to me that I can get all my testing done, whether it be my own internal testing or using an outside lab, and then just file the test reports. There is some mention of the notified body and representative, but not enough for me to feel it necessary to have either. I realize for equipment that doesn't fall under the RTTE Directive, the notified/competent body performs the assessment of the equipment to the particular standards, but isn't the intent of the RTTE Directive to eliminate this requirement and place that burden on the manufacturer? For some reason I just don't see the requirement for those entities after reading through the directive. Maybe someone else can give me their interpretation. Thanks, Courtland Thomas Patton Electronics --- 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,
Test lab with capability for thermal and humidity testing needed
Folks, Can anyone recommend a New England Test lab that has the test capability needed for the following thermal and humidity test for a three bay system and a separate workstation on a cart? -non-operating, -40 to 72 degrees C. 95% humidity. non condensing. -operating 9 to 36 degrees C. 20% to 80% humidity non condensing. We'll need to do both storage and operating temperature tests; as well as control the humidity during the storage test. The station will be moved by the use of crates. The facility needs a forklift or pallet jack to move the unit. If questions, please contact me ASAP. Please reply directly to me at paul.j.sm...@teradyne.com Best Regards,Paul J Smith Teradyne, Inc., Boston, paul.j.sm...@teradyne.com Voice 617-422-2997 Fax 603-843-7526 --- 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)
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
I forgot to mention, however we do test four equipment for emissions to FCC Class B. -Original Message- From: Dick Grobner Sent: Thursday, June 21, 2001 3:33 PM To: 'Tania Grant' Cc: 'emc-p...@majordomo.ieee.org' Subject: RE: FCC + FCC = FCC? - Outlaw Will put Tania and I agree with your reasoning! We don't deal with the FCC as we are a medical manufacturer, but we do deal with the FDA and the Europeans. We are a small medical manufacture compared to the Big Boys and we must play by the same rules! Size and dollars has nothing to do with it and shouldn't. -Original Message- From: Tania Grant [mailto:taniagr...@msn.com] Sent: Thursday, June 21, 2001 11:23 AM To: Doug McKean; emc-p...@majordomo.ieee.org Subject: Re: FCC + FCC = FCC? - Outlaw Hello Doug, I may or may not agree with FCC (on some issues I agree, on others I don't); however, ignorance of the law is no excuse. The FCC Rules do make the assembler responsible for compliance. And the FCC was NOT created to protect big companies from themselves but to allocate spectrum and watch for abuses. The air waves were consigned to bona-fide communication equipment. The early computers were nothing more than super-whiz-bang typewriters-cum-adding machines and not considered communication devices. Thus, they were not supposed to interfere with communication equipment;-- e.g., the Rules. The fact that you can assemble your own, and that you are small fry compared to the big companies, has nothing to do with the fact that your assembled equipment need not comply with the Rules. (I sympathize with small fry, being one myself.) If you disagree with the Rules, you have ample opportunity to write to the FCC and present your case to them;-- they have to publish your letter and present an argument for or against your position. And the FCC in the past has relented and conceded many points when presented with convincing evidence from the industry and from communication companies. (Witness the recent changes to accept DoC instead of the cumbersome Certification procedure for Class B devices.) I believe that this is the democratic and responsible way of addressing the problem rather than disregarding the law because it is inconvenient for you, or because your equipment is just a small pebble in a big pond of boulders and no one will notice. Tania Grant taniagr...@msn.com - Original Message - From: Doug McKean Sent: Thursday, June 21, 2001 12:19 AM To: emc-p...@majordomo.ieee.org 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,
RE: FCC + FCC = FCC? - Outlaw
Will put Tania and I agree with your reasoning! We don't deal with the FCC as we are a medical manufacturer, but we do deal with the FDA and the Europeans. We are a small medical manufacture compared to the Big Boys and we must play by the same rules! Size and dollars has nothing to do with it and shouldn't. -Original Message- From: Tania Grant [mailto:taniagr...@msn.com] Sent: Thursday, June 21, 2001 11:23 AM To: Doug McKean; emc-p...@majordomo.ieee.org Subject: Re: FCC + FCC = FCC? - Outlaw Hello Doug, I may or may not agree with FCC (on some issues I agree, on others I don't); however, ignorance of the law is no excuse. The FCC Rules do make the assembler responsible for compliance. And the FCC was NOT created to protect big companies from themselves but to allocate spectrum and watch for abuses. The air waves were consigned to bona-fide communication equipment. The early computers were nothing more than super-whiz-bang typewriters-cum-adding machines and not considered communication devices. Thus, they were not supposed to interfere with communication equipment;-- e.g., the Rules. The fact that you can assemble your own, and that you are small fry compared to the big companies, has nothing to do with the fact that your assembled equipment need not comply with the Rules. (I sympathize with small fry, being one myself.) If you disagree with the Rules, you have ample opportunity to write to the FCC and present your case to them;-- they have to publish your letter and present an argument for or against your position. And the FCC in the past has relented and conceded many points when presented with convincing evidence from the industry and from communication companies. (Witness the recent changes to accept DoC instead of the cumbersome Certification procedure for Class B devices.) I believe that this is the democratic and responsible way of addressing the problem rather than disregarding the law because it is inconvenient for you, or because your equipment is just a small pebble in a big pond of boulders and no one will notice. Tania Grant taniagr...@msn.com - Original Message - From: Doug McKean Sent: Thursday, June 21, 2001 12:19 AM To: emc-p...@majordomo.ieee.org 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,
RTTE Directive
Hello group, After reading through the RTTE Directive for the fifth or sixth time, I am still not clear on the use of the notified/competent body and European representative. It seems to me that I can get all my testing done, whether it be my own internal testing or using an outside lab, and then just file the test reports. There is some mention of the notified body and representative, but not enough for me to feel it necessary to have either. I realize for equipment that doesn't fall under the RTTE Directive, the notified/competent body performs the assessment of the equipment to the particular standards, but isn't the intent of the RTTE Directive to eliminate this requirement and place that burden on the manufacturer? For some reason I just don't see the requirement for those entities after reading through the directive. Maybe someone else can give me their interpretation. Thanks, Courtland Thomas Patton Electronics --- 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,
Clock Dithering - some more information
I followed the recent discussion threads on this topic, but it is not in my main stream of interest. However, I just remembered an extensive report I had seen on the subject. The report is Investigation into possible effects resulting from dithered clock oscillators on EMC measurements and interference to radio transmission systems By David Lauder and James Moritz of the Univ. of Hertfordshire Regional Electronics Centre, dated 18 March 2000. It was prepared for the UK Radiocommunications Agency. Although I am looking at a paper copy, I am pretty sure that I originally downloaded it from the UK RA website, http://www.radio.gov.uk The report expresses concern about the effects of DCOs on digital TV and COFDM transmissions. 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 --- 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? - Outlaw
20010621143204.UCHV1335.femail1.sdc1.sfba.home.com@[65.11.150.27], Ken Javor ken.ja...@emccompliance.com inimitably wrote: The limits as placed prevent most but not all interference. For instance, some AM radios are susceptible to conducted interference below 48 dBuV. The limits were placed, both in amplitude and frequency, to prevent the large majority of interferences, but not all. Whether it was done right or not may be open to debate, but the philosophy was to optimize: to get the least amount of interference while imposing the minimum design cost impact. Correct. The new(ish) CISPR/H committee is to review these radiated emission limits, some of which are very 'traditional'. -- Regards, John Woodgate, OOO - Own Opinions Only. Phone +44 (0)1268 747839 Fax +44 (0)1268 777124. http://www.jmwa.demon.co.uk Why not call a vertically- applied manulo-pedally-operated quasi-planar chernozem-penetrating and excavating implement a SPADE? --- 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? - Outlaw
Decide among youselves who of you are outlaws ... TITLE 47--TELECOMMUNICATION CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION PART 15--RADIO FREQUENCY DEVICES--Table of Contents Subpart A--General Sec. 15.23 Home-built devices. (a) Equipment authorization is not required for devices that are not marketed, are not constructed from a kit, and are built in quantities of five or less for personal use. (b) It is recognized that the individual builder of home-built equipment may not possess the means to perform the measurements for determining compliance with the regulations. In this case, the builder is expected to employ good engineering practices to meet the specified technical standards to the greatest extent practicable. The provisions of Sec. 15.5 apply to this equipment. - 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,
Re: EMC Safety - Perfect together??/
Hi there, don't think safety and EMC are incompatible. There is an very interesting article about the matter at http://www.iee.org.uk/PAB/EMC/core.htm I think they go by the rule speak softly but carry a big stick Regards Markus Plangger - Original Message - From: chasgra...@aol.com To: taniagr...@msn.com; ken.ja...@emccompliance.com; croni...@hotmail.com; emc-p...@majordomo.ieee.org Sent: Thursday, June 21, 2001 1:01 AM Subject: EMC Safety - Perfect together??/ Hi Tania, Well I think the metric that should be used is the number of user safety related occurences of IT equipment..I'll bet the number is low.!! Having been involved in Safety for a couple of years I was struck by the different approaches that the compliance regulators adopted. To be fair the system level approach IS the correct approach for EMC - after all the final assembly is the mechanism that will radiate or be susceptible. However, the EMC industry is facing a crossroads. If the regulators continue to maintain the current methodology(like King Canute) inspite of the tsunami of electronic products, then I fear there is no future for the standards. After all there are many bright managers out there who will come to the conclusion that the emissions test is voided by the sheer volume of product that is released and the inability of mnufacturers to maintain the compliance without crippling cost and schedule. Chas Grasso --- 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: Safety in General ...
Let me interject a bit here. In the introduction the System Safety Analysis Handbook, published by the System Safety Society (http://www.system-safety.org/), it identifies a hazard control precedence for not only minimizing risk due to the hazard itself, but also to minimize the chances of people bypassing or ignoring the very controls intended to keep them uninjured or alive. It goes like this: 1. Design to eliminate hazardous condition 2. Design for minimum risk 3. Design in safety devices (e.g., interlocks, guards) 4. Design separate warning devices (e.g., lights, audibles, signs) 5. Develop operating procedures and train personnel 6. Develop administrative rules 7. Management decision to accept the risk If the first cannot be met then the second is attempted and so on down the line. There may be cases of multiple levels of precedence of control (e.g., minimum risk design with guards, lights, audibles, signs; and training procedures and manuals that include warnings. Never ever rely only on procedural controls when there is any other method of hazard control. There are many examples beyond those given here that indicate you can't expect everyone to protect themselves. Product manufacturers have no control of the last two in the workplace. Administrative rules are developed by the customer. This is not a shot at management but is a general statement. Those that are in a position to accept the risk are, generally, not those that are exposed to the risk. It makes it easier for one to accept something to which they are not exposed. The only management control we have is to not market the product if we feel it has excessive risk. This hierarchy is opposite to that which some initially propose; tell them not to do it or . . . put a warning label on it. The problem is that to do the top things on the precedence requires the safety people to get involved very early in the development. That often does not happen. Some times the safety department is handed a finished product and told to get it certified/approved. I don't want to sound sarcastic here but I think that the statement: But if the product is being sold to the general public, remember the customer base can have as much as -2 full deviations (that's minus two) from the mean IQ of the population. is a bit optimistic in saying that it can have and -2. I would suggest it does have and the value is greater that -2. Oscar I would recommend the referenced handbook to any who are involved in the art of hazard analysis and evaluation. For the price it is a gold mine of information from many government agencies and corporations both national and international. It comes in a 500+ page loose leaf notebook or on CD. I do not derive any royalties nor does any organization in which I am affiliated with derive any royalties from this product. It's just a good resource. * * Any comments and opinions stated here are my own and * * not of my employer. Any hypothetical statements or* * situations are exactly that and are not representative * * of my current or past employer(s).* * Doug McKean dmckean%corp.auspex@interlock.lexmark.com on 06/21/2001 12:28:55 PM Please respond to Doug McKean dmckean%corp.auspex@interlock.lexmark.com To: EMC-PSTC Discussion Group emc-pstc%ieee@interlock.lexmark.com cc:(bcc: Oscar Overton/Lex/Lexmark) Subject: Safety in General ... Tania Grant wrote: Doug, If I understand you correctly, you are referring to the remaining connector (or pins or traces) in the equipment which is still under power. Yes. O.K., let me tell you what UL and CSA made me do with equipment that is NOT user accessible, but only accessible to trained service personnel. Yes. This is a perfect case of required warnings being used no matter if the person is an end user or repairer. snipped material Never underestimate the stupidity of people challenged by some intriguing label or instruction! However, a trained serviceman should accept your label at face value. Yes, I had an interesting case with a laser and a trained technician once. Seems he decided to look down the fiber to check if the laser was on. It was an IR device (invisible to the naked eye) and running at about 15mW. When I was asked about it by marketing, I said, make sure to tell the technician not to look at the laser with his remaining good eye ... Luckily, the guy wasn't harmed, but they got the point. Unintended consequences abound, but it is not our responsibility to design simple common sense into everything that's made. It's our responsibility for due diligence, good engineering practices, safety, etc ... But if the product is being sold to the general public, remember the customer base can have as much as -2 full deviations
RE: Hot Swappable Power Supplies ?
Gary, is the hot swappable approval included in the UL Conditions of Acceptability or is a different component category? Richard Woods -- From: Gary McInturff [SMTP:gary.mcintu...@worldwidepackets.com] Sent: Thursday, June 21, 2001 11:41 AM To: 'Lesmeister, Glenn'; emc-p...@ieee.org Subject: RE: Hot Swappable Power Supplies ? They have hot swappable connectors that have already been subjected to the test as part of the component recognition, but I don't remember the CCN number. -Original Message- From: Lesmeister, Glenn [mailto:glenn.lesmeis...@compaq.com] Sent: Thursday, June 21, 2001 6:26 AM To: emc-p...@ieee.org Subject: RE: Hot Swappable Power Supplies ? Richard, What is the test plan for making and breaking under load? In general, power supplies take a little bit of time to start up, so making contact under load is not going to be an issue. UL has specified a 200 cycle disconnect test and all they are concerned with is condition of the contacts afterward. They do not specify how fast you have to plug the supply from the connector, so this could be a factor. Typically, they have a short signal pin that must be fully seated for the supply to operate. Once you start pulling the supply, the signal pin breaks first and shuts down the high current before those contacts break. The slower you pull, the less likely you will draw an arc. Or course, the fast you pull, the shorter duration the arc. Regards, Glenn Lesmeister Product Regulatory Compliance Compaq Computer Corp. Tel: 281-514-5163 20555 SH 249, MS60607 Fax: 281-514-8029 Houston, TX 77070-2698 Pgr: 713-786-4930 glenn.lesmeis...@compaq.com I am empowered to do what makes sense! -Original Message- From: wo...@sensormatic.com [mailto:wo...@sensormatic.com] Sent: Thursday, June 21, 2001 6:35 AM To: emc-p...@ieee.org Subject:RE: Hot Swappable Power Supplies ? We are currently evaluating a system with hot swappable power supplies and PCBs and here is what we have found needs to be checked: o Earthing pin makes first and breaks last o Primary and secondary power connectors are rated for make/break application o Access to hazardous voltages and energy hazards o Capacity of paralleled outputs may exceed energy hazard limits (we are adding PTCs on the backplane for each PCB which are also hot swappable) Richard Woods -- From: Richardson, William G [SMTP:william.richard...@unisys.com] Sent: Wednesday, June 20, 2001 5:50 PM To: 'Dan Teninty' Cc: 'emc-p...@ieee.org' Subject: RE: Hot Swappable Power Supplies ? There must be a bleeder resistor (across the X caps) to make the AC input pins safe to touch once the supply is removed from the cabinet. If there are exposed voltage or energy hazards with the supply removed, there must be a restriction such that only trained personnel are instructed to do this OR a tool must be used to remove the supply. -Original Message- From: Dan Teninty [mailto:dteni...@dtec-associates.com] Sent: Wednesday, June 20, 2001 4:16 PM To: Emc-Pstc@Majordomo. Ieee. Org Subject: Hot Swappable Power Supplies ? Do any of my esteemed colleagues know of any specific requirements in 60950 (UL/CSA or EN) relating specifically to hot swappable power supplies? A search in the PDF version of UL/CSA 60950 reveals nothing specific when searching for hot, swap, or power supply. A visual search of the TOC also reveals nothing specific. 2.6.5.4 deals with : Parts that can be removed by an operator Protective earthing connections shall make earlier and break later than the supply connections in each of the following: - the connector of a part that can be removed by an OPERATOR; - a plug on a power supply cord; - an appliance coupler. Compliance is checked by inspection. This is the most I could find that was related, and then it is referring to the AC side. Thought I would triple check with the collective brain trust to be
Safety in General ...
Tania Grant wrote: Doug, If I understand you correctly, you are referring to the remaining connector (or pins or traces) in the equipment which is still under power. Yes. O.K., let me tell you what UL and CSA made me do with equipment that is NOT user accessible, but only accessible to trained service personnel. Yes. This is a perfect case of required warnings being used no matter if the person is an end user or repairer. snipped material Never underestimate the stupidity of people challenged by some intriguing label or instruction! However, a trained serviceman should accept your label at face value. Yes, I had an interesting case with a laser and a trained technician once. Seems he decided to look down the fiber to check if the laser was on. It was an IR device (invisible to the naked eye) and running at about 15mW. When I was asked about it by marketing, I said, make sure to tell the technician not to look at the laser with his remaining good eye ... Luckily, the guy wasn't harmed, but they got the point. Unintended consequences abound, but it is not our responsibility to design simple common sense into everything that's made. It's our responsibility for due diligence, good engineering practices, safety, etc ... But if the product is being sold to the general public, remember the customer base can have as much as -2 full deviations (that's minus two) from the mean IQ of the population. - 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,
Re: FCC + FCC = FCC? - Outlaw
Hello Doug, I may or may not agree with FCC (on some issues I agree, on others I don't); however, ignorance of the law is no excuse. The FCC Rules do make the assembler responsible for compliance. And the FCC was NOT created to protect big companies from themselves but to allocate spectrum and watch for abuses. The air waves were consigned to bona-fide communication equipment. The early computers were nothing more than super-whiz-bang typewriters-cum-adding machines and not considered communication devices. Thus, they were not supposed to interfere with communication equipment;-- e.g., the Rules. The fact that you can assemble your own, and that you are small fry compared to the big companies, has nothing to do with the fact that your assembled equipment need not comply with the Rules. (I sympathize with small fry, being one myself.) If you disagree with the Rules, you have ample opportunity to write to the FCC and present your case to them;-- they have to publish your letter and present an argument for or against your position.And the FCC in the past has relented and conceded many points when presented with convincing evidence from the industry and from communication companies. (Witness the recent changes to accept DoC instead of the cumbersome Certification procedure for Class B devices.) I believe that this is the democratic and responsible way of addressing the problem rather than disregarding the law because it is inconvenient for you, or because your equipment is just a small pebble in a big pond of boulders and no one will notice. Tania Grant taniagr...@msn.com - Original Message - From: Doug McKean Sent: Thursday, June 21, 2001 12:19 AM To: emc-p...@majordomo.ieee.org 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,
Re: Solstice electrical shutdown
If there's a significant drop in the current demand of a power grid, the voltage of that grid could possibly jump. If enough of the loads are dropped, I guess there might be some power factor issues and power reflections back to the companies. Not sure, but I think a large reflection bouncing around the Northeast grid is what popped most of the substations during the famous power outage in New England during the 60's. - 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,
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: Hot Swappable Power Supplies ?
They have hot swappable connectors that have already been subjected to the test as part of the component recognition, but I don't remember the CCN number. -Original Message- From: Lesmeister, Glenn [mailto:glenn.lesmeis...@compaq.com] Sent: Thursday, June 21, 2001 6:26 AM To: emc-p...@ieee.org Subject: RE: Hot Swappable Power Supplies ? Richard, What is the test plan for making and breaking under load? In general, power supplies take a little bit of time to start up, so making contact under load is not going to be an issue. UL has specified a 200 cycle disconnect test and all they are concerned with is condition of the contacts afterward. They do not specify how fast you have to plug the supply from the connector, so this could be a factor. Typically, they have a short signal pin that must be fully seated for the supply to operate. Once you start pulling the supply, the signal pin breaks first and shuts down the high current before those contacts break. The slower you pull, the less likely you will draw an arc. Or course, the fast you pull, the shorter duration the arc. Regards, Glenn Lesmeister Product Regulatory Compliance Compaq Computer Corp. Tel: 281-514-5163 20555 SH 249, MS60607 Fax: 281-514-8029 Houston, TX 77070-2698 Pgr: 713-786-4930 glenn.lesmeis...@compaq.com I am empowered to do what makes sense! -Original Message- From: wo...@sensormatic.com [mailto:wo...@sensormatic.com] Sent: Thursday, June 21, 2001 6:35 AM To: emc-p...@ieee.org Subject:RE: Hot Swappable Power Supplies ? We are currently evaluating a system with hot swappable power supplies and PCBs and here is what we have found needs to be checked: o Earthing pin makes first and breaks last o Primary and secondary power connectors are rated for make/break application o Access to hazardous voltages and energy hazards o Capacity of paralleled outputs may exceed energy hazard limits (we are adding PTCs on the backplane for each PCB which are also hot swappable) Richard Woods -- From: Richardson, William G [SMTP:william.richard...@unisys.com] Sent: Wednesday, June 20, 2001 5:50 PM To: 'Dan Teninty' Cc: 'emc-p...@ieee.org' Subject: RE: Hot Swappable Power Supplies ? There must be a bleeder resistor (across the X caps) to make the AC input pins safe to touch once the supply is removed from the cabinet. If there are exposed voltage or energy hazards with the supply removed, there must be a restriction such that only trained personnel are instructed to do this OR a tool must be used to remove the supply. -Original Message- From: Dan Teninty [mailto:dteni...@dtec-associates.com] Sent: Wednesday, June 20, 2001 4:16 PM To: Emc-Pstc@Majordomo. Ieee. Org Subject: Hot Swappable Power Supplies ? Do any of my esteemed colleagues know of any specific requirements in 60950 (UL/CSA or EN) relating specifically to hot swappable power supplies? A search in the PDF version of UL/CSA 60950 reveals nothing specific when searching for hot, swap, or power supply. A visual search of the TOC also reveals nothing specific. 2.6.5.4 deals with : Parts that can be removed by an operator Protective earthing connections shall make earlier and break later than the supply connections in each of the following: - the connector of a part that can be removed by an OPERATOR; - a plug on a power supply cord; - an appliance coupler. Compliance is checked by inspection. This is the most I could find that was related, and then it is referring to the AC side. Thought I would triple check with the collective brain trust to be sure. Appreciate any pointers to passages that I missed. Thanks, Daniel E. Teninty, P.E. Managing Partner DTEC Associates LLC Streamlining the Compliance Process 5406 S. Glendora Drive Spokane, WA 99223 (509) 443-0215 (509) 443-0181 fax --- 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
Re: Hot Swappable Power Supplies ?
It comes from the nice new one UL60950. First time I encountered it was a new product submitted for approval in January. One thing though it only applies if the power supply can be removed by the operator. If it is a service removable item, i.e. screwed in place, then the test was not required. Kealey, Doug wrote: Please let us know which UL standard contains this test. I'm sure you've aroused everyone's curiosity. Thanks, Doug -Original Message- From: acar...@uk.xyratex.com [mailto:acar...@uk.xyratex.com] Sent: Thursday, June 21, 2001 4:38 AM To: emc-p...@ieee.org Subject: Re: Hot Swappable Power Supplies ? Another UL specific test to consider it the Connector Current Interrupt Test. Hot plug your device 200 times and recheck the dielectric strength and earth path. It is a new UL requirements and the test sheet currently does not have a number on it. Well not he one I had to fill in the other month. kazimier_gawrzy...@dell.com wrote: Dan, Without knowing any detail on your product, my vote is to say that all of the requirements of 60950 that apply to any other power supply would apply in full to a hot swappable supply. Assuming the supply you're handling is akin to a bank of rectifiers in a shelf, the shelf would also need space fillers to close off access to hazardous parts in the event that a full complement of supplies is not used. I assume the over-all design addresses in-rush currents at both the supply and shelf ends, labels, warnings, instructions, etcthe full monty. My opinion and not that of my employer. Regards, Kaz Gawrzyjal kazimier_gawrzy...@dell.com -Original Message- From: Richardson, William G [mailto:william.richard...@unisys.com] Sent: Wednesday, June 20, 2001 4:50 PM To: 'Dan Teninty' Cc: 'emc-p...@ieee.org' Subject: RE: Hot Swappable Power Supplies ? There must be a bleeder resistor (across the X caps) to make the AC input pins safe to touch once the supply is removed from the cabinet. If there are exposed voltage or energy hazards with the supply removed, there must be a restriction such that only trained personnel are instructed to do this OR a tool must be used to remove the supply. -Original Message- From: Dan Teninty [mailto:dteni...@dtec-associates.com] Sent: Wednesday, June 20, 2001 4:16 PM To: Emc-Pstc@Majordomo. Ieee. Org Subject: Hot Swappable Power Supplies ? Do any of my esteemed colleagues know of any specific requirements in 60950 (UL/CSA or EN) relating specifically to hot swappable power supplies? A search in the PDF version of UL/CSA 60950 reveals nothing specific when searching for hot, swap, or power supply. A visual search of the TOC also reveals nothing specific. 2.6.5.4 deals with : Parts that can be removed by an operator Protective earthing connections shall make earlier and break later than the supply connections in each of the following: - the connector of a part that can be removed by an OPERATOR; - a plug on a power supply cord; - an appliance coupler. Compliance is checked by inspection. This is the most I could find that was related, and then it is referring to the AC side. Thought I would triple check with the collective brain trust to be sure. Appreciate any pointers to passages that I missed. Thanks, Daniel E. Teninty, P.E. Managing Partner DTEC Associates LLC Streamlining the Compliance Process 5406 S. Glendora Drive Spokane, WA 99223 (509) 443-0215 (509) 443-0181 fax --- 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
RE: FCC + FCC = FCC?
Bonjour de Montréal, The FCC regulation allows the construction and marking (see FCC2.jpg) of PC when they are assembled using separately authorized components. Here are a copies of sections of the FCC regulation 15.19 Labelling requirements. (a) In addition to the requirements in Part 2 of this chapter, a device subject to certification or verification shall be labelled as follows: (1) Receivers associated with the operation of a licensed radio service, e.g., FM broadcast under Part 73 of this chapter, land mobile operation under Part 90, etc., shall bear the following statement in a conspicuous location on the device: This device complies with Part 15 of the FCC Rules. Operation is subject to the condition that this device does not cause harmful interference. (2) A stand-alone cable input selector switch, shall bear the following statement in a conspicuous location on the device: This device is verified to comply with Part 15 of the FCC Rules for use with cable television service. (3) All other devices shall bear the following statement in a conspicuous location on the device: This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. (4) Where a device is constructed in two or more sections connected by wires and marketed together, the statement specified under paragraph (a) of this section is required to be affixed only to the main control unit. (5) When the device is so small or for such use that it is not practicable to place the statement specified under paragraph (a) of this section on it, the information required by this paragraph shall be placed in a prominent location in the instruction manual or pamphlet supplied to the user or, alternatively, shall be placed on the container in which the device is marketed. However, the FCC identifier or the unique identifier, as appropriate, must be displayed on the device. (b) Products subject to authorization under a Declaration of Conformity shall be labelled as follows: (1) The label shall be located in a conspicuous location on the device and shall contain the unique identification described in §2.1074 of this chapter and the following logo: (i) If the product is authorized based on testing of the product or system; or See FCC1.jpg (ii) If a personal computer is authorized based on assembly using separately authorized components, in accordance with §15.101(c)(2) or (c)(3), and the resulting product is not separately tested: SEE FCC2.jpg2 Copy of 15.101 (c) Personal computers shall be authorized in accordance with one of the following methods: (2) The personal computer is authorized under a Declaration of Conformity or a grant of certification, and the CPU board or power supply in that computer is replaced with a CPU board or power supply that has been separately authorized under a Declaration of Conformity or a grant of certification; or (3) The CPU board and power supply used in the assembly of a personal computer have been separately authorized under a Declaration of Conformity or a grant of certification; and Hope this help Regards, == Benoît Nadeau, ing., M.ing. (P.Eng., M.Eng) Gérant du Groupe Conformité (Conformity Group Manager) Matrox 1055 boul. St-Regis Dorval (Quebec) Canada H9P 2T4 == Tel : (514) 822-6000 (2475) Fax : (514) 822-6275 mailto:bnad...@matrox.com http://www.matrox.com == Président / Chairman 2001 IEEE International Symposium on Electromagnetic Compatibility mailto:bnad...@ieee.org http://www.2001emcmtl.org -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Ralph Cameron Sent: Thursday, June 21, 2001 09:18 To: Doug McKean; EMC-PSTC Discussion Group Subject: 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
Re: FCC + FCC = FCC? - Outlaw
The reason for the FCC disclaimer is not what you say (although it is satisfying to think so). The limits as placed prevent most but not all interference. For instance, some AM radios are susceptible to conducted interference below 48 dBuV. The limits were placed, both in amplitude and frequency, to prevent the large majority of interferences, but not all. Whether it was done right or not may be open to debate, but the philosophy was to optimize: to get the least amount of interference while imposing the minimum design cost impact. Hence the disclaimer that says that if interference to broadcast reception still occurs, it is your responsibility to ameliorate it, up to and including ceasing usage of the offending device. -- From: Doug McKean dmck...@gte.net To: emc-p...@majordomo.ieee.org Subject: RE: FCC + FCC = FCC? - Outlaw Date: Thu, Jun 21, 2001, 1:32 AM 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: Hot Swappable Power Supplies ?
Richard, What is the test plan for making and breaking under load? In general, power supplies take a little bit of time to start up, so making contact under load is not going to be an issue. UL has specified a 200 cycle disconnect test and all they are concerned with is condition of the contacts afterward. They do not specify how fast you have to plug the supply from the connector, so this could be a factor. Typically, they have a short signal pin that must be fully seated for the supply to operate. Once you start pulling the supply, the signal pin breaks first and shuts down the high current before those contacts break. The slower you pull, the less likely you will draw an arc. Or course, the fast you pull, the shorter duration the arc. Regards, Glenn Lesmeister Product Regulatory Compliance Compaq Computer Corp. Tel: 281-514-5163 20555 SH 249, MS60607 Fax: 281-514-8029 Houston, TX 77070-2698 Pgr: 713-786-4930 glenn.lesmeis...@compaq.com I am empowered to do what makes sense! -Original Message- From: wo...@sensormatic.com [mailto:wo...@sensormatic.com] Sent: Thursday, June 21, 2001 6:35 AM To: emc-p...@ieee.org Subject:RE: Hot Swappable Power Supplies ? We are currently evaluating a system with hot swappable power supplies and PCBs and here is what we have found needs to be checked: o Earthing pin makes first and breaks last o Primary and secondary power connectors are rated for make/break application o Access to hazardous voltages and energy hazards o Capacity of paralleled outputs may exceed energy hazard limits (we are adding PTCs on the backplane for each PCB which are also hot swappable) Richard Woods -- From: Richardson, William G [SMTP:william.richard...@unisys.com] Sent: Wednesday, June 20, 2001 5:50 PM To: 'Dan Teninty' Cc: 'emc-p...@ieee.org' Subject: RE: Hot Swappable Power Supplies ? There must be a bleeder resistor (across the X caps) to make the AC input pins safe to touch once the supply is removed from the cabinet. If there are exposed voltage or energy hazards with the supply removed, there must be a restriction such that only trained personnel are instructed to do this OR a tool must be used to remove the supply. -Original Message- From: Dan Teninty [mailto:dteni...@dtec-associates.com] Sent: Wednesday, June 20, 2001 4:16 PM To: Emc-Pstc@Majordomo. Ieee. Org Subject: Hot Swappable Power Supplies ? Do any of my esteemed colleagues know of any specific requirements in 60950 (UL/CSA or EN) relating specifically to hot swappable power supplies? A search in the PDF version of UL/CSA 60950 reveals nothing specific when searching for hot, swap, or power supply. A visual search of the TOC also reveals nothing specific. 2.6.5.4 deals with : Parts that can be removed by an operator Protective earthing connections shall make earlier and break later than the supply connections in each of the following: - the connector of a part that can be removed by an OPERATOR; - a plug on a power supply cord; - an appliance coupler. Compliance is checked by inspection. This is the most I could find that was related, and then it is referring to the AC side. Thought I would triple check with the collective brain trust to be sure. Appreciate any pointers to passages that I missed. Thanks, Daniel E. Teninty, P.E. Managing Partner DTEC Associates LLC Streamlining the Compliance Process 5406 S. Glendora Drive Spokane, WA 99223 (509) 443-0215 (509) 443-0181 fax --- 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:
RE: Taiwan BSMI - Jian Ci Wording
I want to thank the many people who responded to my request, and who supplied graphic files for the Chinese wording. Jim Lyons -Original Message- From: Lyons, Jim Sent: Thursday, June 14, 2001 2:56 PM To: 'emc-p...@ieee.org' Subject: Taiwan BSMI - Jian Ci Wording Taiwan's BSMI requires approved, class A ITE products have a label with the traditional Chinese symbols Jian Ci followed by the assigned registration number, along with a Class A warning statement, also in traditional Chinese, on a label and in the manual. I have some mediocre quality pdf documents showing the required characters and statement, but have been unsuccessful in finding higher quality graphic representations that I could use for making the production labels and in the manual. Does someone have this information in a jpg, gif, tiff, bmp, or some other graphics format? Thanks, Jim Lyons --- 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,
Automotive transients ISO 7637 Part 3
Hi group, I was browsing the ISO website and discovered a part 3 to ISO 7637. Does anyone know if there are new automotive test pulses not already covered by part 1 (12V vehicles) and part 2 (24V vehicles)? The brief on part 3 seems to address vehicles powered from 12 and/or 24V sources. Regards - Chris Chileshe - Ultronics Ltd _ 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: http://www.rcic.com/ click on Virtual Conference Hall,
RE: Solstice electrical shutdown
Parts of the power grid go off line most any day without major consequences. Richard Woods -- From: Robert Johnson [SMTP:robe...@ma.ultranet.com] Sent: Thursday, June 21, 2001 8:14 AM To: PSTC Subject: Solstice electrical shutdown I've been wondering about the safety consequences of the suggested load shedding expected tonight. A chain letter which has gained a lot of popularity recommends turning off all electrical use from 7 to 10pm in celebration of the solstice and in reaction to the recent west coast power problems. If a significant portion of the country suddenly sheds load at a specific time, will the utililities be ready? What are the consequences for voltage and frequency regulation as generating capacity is faced with a sudden load drop? I don't know the degree of participation expected nationwide, but there has been a lot of coverage about this from Jay Leno to NPR. Possibly the rest of us should participate just to protect our appliances. Bob --- 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: Hot Swappable Power Supplies ?
Here are several 60950 issues: 1) Are exposed hot terminals accessable when P/S is removed? Depending on whether the power supplies are 'shared' or switchover' and types of diode protection, there may be hazardous voltages or currents on the connectors (check the amperage and joule availablity). If so you need hazard and alert stickers, plus warnings in the manual. Is there a door in case one P/S is rotated for replacement? A removable cover will be discarded so a door is better. 2) Are there dual linecords? Dual linecords require an alert sticker and warning in all languages (MULTIPLE POWER SOURCES; DISCONNECT BOTH POWER SUPPLIES BEFORE SERVICING). Define any limitations or recommendations for using separate branch circuits (great redundancy but possible international earthing problems). 3) If unit is hard wired to mains, there are more considerations (disconnect device (double-pole circuit breaker), fusing, etc). David Sterner -Original Message- From: Dan Teninty [mailto:dteni...@dtec-associates.com] Sent: Wednesday, June 20, 2001 5:16 PM To: Emc-Pstc@Majordomo. Ieee. Org Subject: Hot Swappable Power Supplies ? Do any of my esteemed colleagues know of any specific requirements in 60950 (UL/CSA or EN) relating specifically to hot swappable power supplies? A search in the PDF version of UL/CSA 60950 reveals nothing specific when searching for hot, swap, or power supply. A visual search of the TOC also reveals nothing specific. 2.6.5.4 deals with : Parts that can be removed by an operator Protective earthing connections shall make earlier and break later than the supply connections in each of the following: - the connector of a part that can be removed by an OPERATOR; - a plug on a power supply cord; - an appliance coupler. Compliance is checked by inspection. This is the most I could find that was related, and then it is referring to the AC side. Thought I would triple check with the collective brain trust to be sure. Appreciate any pointers to passages that I missed. Thanks, Daniel E. Teninty, P.E. Managing Partner DTEC Associates LLC Streamlining the Compliance Process 5406 S. Glendora Drive Spokane, WA 99223 (509) 443-0215 (509) 443-0181 fax --- 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,
Solstice electrical shutdown
I've been wondering about the safety consequences of the suggested load shedding expected tonight. A chain letter which has gained a lot of popularity recommends turning off all electrical use from 7 to 10pm in celebration of the solstice and in reaction to the recent west coast power problems. If a significant portion of the country suddenly sheds load at a specific time, will the utililities be ready? What are the consequences for voltage and frequency regulation as generating capacity is faced with a sudden load drop? I don't know the degree of participation expected nationwide, but there has been a lot of coverage about this from Jay Leno to NPR. Possibly the rest of us should participate just to protect our appliances. Bob --- 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: Hot Swappable Power Supplies ?
We are currently evaluating a system with hot swappable power supplies and PCBs and here is what we have found needs to be checked: o Earthing pin makes first and breaks last o Primary and secondary power connectors are rated for make/break application o Access to hazardous voltages and energy hazards o Capacity of paralleled outputs may exceed energy hazard limits (we are adding PTCs on the backplane for each PCB which are also hot swappable) Richard Woods -- From: Richardson, William G [SMTP:william.richard...@unisys.com] Sent: Wednesday, June 20, 2001 5:50 PM To: 'Dan Teninty' Cc: 'emc-p...@ieee.org' Subject: RE: Hot Swappable Power Supplies ? There must be a bleeder resistor (across the X caps) to make the AC input pins safe to touch once the supply is removed from the cabinet. If there are exposed voltage or energy hazards with the supply removed, there must be a restriction such that only trained personnel are instructed to do this OR a tool must be used to remove the supply. -Original Message- From: Dan Teninty [mailto:dteni...@dtec-associates.com] Sent: Wednesday, June 20, 2001 4:16 PM To: Emc-Pstc@Majordomo. Ieee. Org Subject: Hot Swappable Power Supplies ? Do any of my esteemed colleagues know of any specific requirements in 60950 (UL/CSA or EN) relating specifically to hot swappable power supplies? A search in the PDF version of UL/CSA 60950 reveals nothing specific when searching for hot, swap, or power supply. A visual search of the TOC also reveals nothing specific. 2.6.5.4 deals with : Parts that can be removed by an operator Protective earthing connections shall make earlier and break later than the supply connections in each of the following: - the connector of a part that can be removed by an OPERATOR; - a plug on a power supply cord; - an appliance coupler. Compliance is checked by inspection. This is the most I could find that was related, and then it is referring to the AC side. Thought I would triple check with the collective brain trust to be sure. Appreciate any pointers to passages that I missed. Thanks, Daniel E. Teninty, P.E. Managing Partner DTEC Associates LLC Streamlining the Compliance Process 5406 S. Glendora Drive Spokane, WA 99223 (509) 443-0215 (509) 443-0181 fax --- 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:
Re: Hot Swappable Power Supplies ?
oe49kqvsdtdh2iwpj5td...@hotmail.com, Tania Grant taniagr...@msn.com inimitably wrote: However, the CSA evaluating engineer made us place a label, such as when the supply was pulled out, the label immediately were made visible, that stated the usual WARNING! Hazardous Energy! ... Well, for the cost of a label, it was probably worth it. You are lucky not to have met a 'safety crusader' who insisted on an interlock! If this is user accessible equipment, you can't even rely on such a label! The user might decide to try what Hazardous Energy feels like! Or not know English, or be dyslexic or -- Regards, John Woodgate, OOO - Own Opinions Only. Phone +44 (0)1268 747839 Fax +44 (0)1268 777124. http://www.jmwa.demon.co.uk Why not call a vertically- applied manulo-pedally-operated quasi-planar chernozem-penetrating and excavating implement a SPADE? --- 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: You won't believe this ... Well, maybe you will.
oe6ymq1we9ql2rkes8y0002c...@hotmail.com, Tania Grant taniagr...@msn.com inimitably wrote: However, I believe that standards should use all three precepts as necessary rather than an ascension order as you state. You have introduced a higher level of insight. What is *specified* is not necessarily *what is evaluated*. For example, it is required that printed circuit board material is fire-resistant according to a defined test. But it is NOT necessary to actually test it, if it is clearly made of a material known to be satisfactory. On the other hand, it is wrong to specify that it must be of grade XYZ, without the option of testing the performance of, for example, a special SHF board material that is not within the 'grade XYZ' specification because it's basically PTFE, not glass-epoxy. For example, for fire mitigation, UL uses all three approaches: performance (subjects plastics to fire tests), construction (types of enclosure, hole openings), and design (parts in low current power limited circuits have different requirements). I think UL has some way to go, though, in choosing performance specifications *for preference* over construction or design. In contrast, Bellcore GR-63-CORE torches the complete system to prove fire safety and subjects printed circuits to airborne contaminants (thereby absolutely destroying them) to prove pass or fail parameters by performance. I think that it is wrong and unreasonable to destroy equipment that costs hundreds of thousands of dollars to prove a pass or fail condition. And unnecessary when judicious design and construction requirements could achieve similar results. I quite agree: such an approach does not take into account the data obtained by previous testing and certification. Specifications of construction or design in fact depend on past testing to determine 'what we know works'. I think that all three are necessary in proper combination. UL is not a saint, but I believe that they have a more rational approach than burning equipment,-- like witches were burned in the Dark Ages to prove their fair or foul status. Agreed, especially as ladies who second-guessed men were very liable to be denounced in the bad old days. (;-) -- Regards, John Woodgate, OOO - Own Opinions Only. Phone +44 (0)1268 747839 Fax +44 (0)1268 777124. http://www.jmwa.demon.co.uk Why not call a vertically- applied manulo-pedally-operated quasi-planar chernozem-penetrating and excavating implement a SPADE? --- 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: Hot Swappable Power Supplies ?
Another UL specific test to consider it the Connector Current Interrupt Test. Hot plug your device 200 times and recheck the dielectric strength and earth path. It is a new UL requirements and the test sheet currently does not have a number on it. Well not he one I had to fill in the other month. kazimier_gawrzy...@dell.com wrote: Dan, Without knowing any detail on your product, my vote is to say that all of the requirements of 60950 that apply to any other power supply would apply in full to a hot swappable supply. Assuming the supply you're handling is akin to a bank of rectifiers in a shelf, the shelf would also need space fillers to close off access to hazardous parts in the event that a full complement of supplies is not used. I assume the over-all design addresses in-rush currents at both the supply and shelf ends, labels, warnings, instructions, etcthe full monty. My opinion and not that of my employer. Regards, Kaz Gawrzyjal kazimier_gawrzy...@dell.com -Original Message- From: Richardson, William G [mailto:william.richard...@unisys.com] Sent: Wednesday, June 20, 2001 4:50 PM To: 'Dan Teninty' Cc: 'emc-p...@ieee.org' Subject: RE: Hot Swappable Power Supplies ? There must be a bleeder resistor (across the X caps) to make the AC input pins safe to touch once the supply is removed from the cabinet. If there are exposed voltage or energy hazards with the supply removed, there must be a restriction such that only trained personnel are instructed to do this OR a tool must be used to remove the supply. -Original Message- From: Dan Teninty [mailto:dteni...@dtec-associates.com] Sent: Wednesday, June 20, 2001 4:16 PM To: Emc-Pstc@Majordomo. Ieee. Org Subject: Hot Swappable Power Supplies ? Do any of my esteemed colleagues know of any specific requirements in 60950 (UL/CSA or EN) relating specifically to hot swappable power supplies? A search in the PDF version of UL/CSA 60950 reveals nothing specific when searching for hot, swap, or power supply. A visual search of the TOC also reveals nothing specific. 2.6.5.4 deals with : Parts that can be removed by an operator Protective earthing connections shall make earlier and break later than the supply connections in each of the following: - the connector of a part that can be removed by an OPERATOR; - a plug on a power supply cord; - an appliance coupler. Compliance is checked by inspection. This is the most I could find that was related, and then it is referring to the AC side. Thought I would triple check with the collective brain trust to be sure. Appreciate any pointers to passages that I missed. Thanks, Daniel E. Teninty, P.E. Managing Partner DTEC Associates LLC Streamlining the Compliance Process 5406 S. Glendora Drive Spokane, WA 99223 (509) 443-0215 (509) 443-0181 fax --- 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:
Re: You won't believe this ... Well, maybe you will.
John, I have no problem with your second paragraph; it makes sense. However, I believe that standards should use all three precepts as necessary rather than an ascension order as you state. For example, for fire mitigation, UL uses all three approaches: performance (subjects plastics to fire tests), construction (types of enclosure, hole openings), and design (parts in low current power limited circuits have different requirements). In contrast, Bellcore GR-63-CORE torches the complete system to prove fire safety and subjects printed circuits to airborne contaminants (thereby absolutely destroying them) to prove pass or fail parameters by performance. I think that it is wrong and unreasonable to destroy equipment that costs hundreds of thousands of dollars to prove a pass or fail condition.. And unnecessary when judicious design and construction requirements could achieve similar results. I think that all three are necessary in proper combination. UL is not a saint, but I believe that they have a more rational approach than burning equipment,-- like witches were burned in the Dark Ages to prove their fair or foul status. Tania Grant taniagr...@msn.com - Original Message - From: John Woodgate Sent: Wednesday, June 20, 2001 9:13 AM To: emc-p...@majordomo.ieee.org Subject: Re: You won't believe this ... Well, maybe you will. 002501c0f905$794dabe0$3e3e3...@corp.auspex.com, Doug McKean dmck...@corp.auspex.com inimitably wrote: 1. Have any you ever run into something like this before? 2. If you have, what did you do about it? I would say that a safety standard that specifies a cfm rating for a fan is a badly-drafted standard. I would press to get the standard changed. What matters for safety is the temperature that parts can reach. If they are OK, under both normal and fault conditions, the equipment should pass. This is an example of a fundamental principle of prescriptive standardization: 1. If possible, specify performance: it's what matters and is usually easy to verify. 2. If it isn't possible/practicable to verify performance (e.g. if long- term durability is involved), specify construction. 3. If it isn't possible/practicable to specify construction (e.g. because many constructions would be satisfactory), specify design. In this case, specifying performance - temperature rises under normal and fault conditions - is the normal practice. Specifying the cfm is specifying design, and there seems no good reason for that. -- Regards, John Woodgate, OOO - Own Opinions Only. Phone +44 (0)1268 747839 Fax +44 (0)1268 777124. http://www.jmwa.demon.co.uk Why not call a vertically- applied manulo-pedally-operated quasi-planar chernozem-penetrating and excavating implement a SPADE? --- 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: Hot Swappable Power Supplies ?
Doug, If I understand you correctly, you are referring to the remaining connector (or pins or traces) in the equipment which is still under power. O.K., let me tell you what UL and CSA made me do with equipment that is NOT user accessible, but only accessible to trained service personnel. There was no hazardous voltage (equipment was -48 Vdc nominal); however, there was definitely Hazardous Energy if the serviceman pushed his hand inside up to his elbow, and if his nails were decorated with metal studs or if he somehow managed to bridge with a tool in a very narrow tube-like area. We never thought that this type of deliberate sabotage was likely to occur. However, the CSA evaluating engineer made us place a label, such as when the supply was pulled out, the label immediately were made visible, that stated the usual WARNING! Hazardous Energy! ... If this is user accessible equipment, you can't even rely on such a label! The user might decide to try what Hazardous Energy feels like! O.K., here comes another story! In my late twenties, when braces were not so frequently worn by even kids, I found myself with a full set of braces. The orthodontist warned me not to bite into apples (eat slices instead), not to crack nuts with my teeth, etc, etc, and not to chew gum. Gum? I never chew gum, but I was intrigued. What possible harm could some soft gum do to you? So I bought some gum and proceeded to chew. In the beginning there was absolutely no problem. Then later, when the gum lost its sugar and other additives (and remained pure rubber or latex or whatever it transmorphed into) the whole goop stuck to the braces and in between and underneath the wires. It took me at least 40 minutes with a toothpick to dislodge tiny bits of gum that were stuck all over the braces. It was more than a day that I really felt I got all of it out. Never underestimate the stupidity of people challenged by some intriguing label or instruction! However, a trained serviceman should accept your label at face value. Tania Grant taniagr...@msn.com - Original Message - From: Doug McKean Sent: Wednesday, June 20, 2001 6:31 PM To: EMC-PSTC Discussion Group Subject: Re: Hot Swappable Power Supplies ? What's the accessibility to pins or traces or anything carrying hazardous energy when a power supply is pulled out? - Doug --- 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? - 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,
Re: Radio controlled aircraft (toys)
Dear Mr. Chan: Part 95 ..is.. the FCC Part which covers radio control transmissions. Subpart C is titles Radio Controlled (RC) Radio Services. Paragraph 95.207 specifies the frequencies which may be used. These are in the 26-27 MHz and 72-76 MHz ranges, and must only be specific frequencies. You should also read Subpart E Technical Regulations. I believe low-power Part 15 operation can be used, this on most frequencies except those specifically prohibited (Restricted Bands). The problem is that the power level permitted is so low that it is unlikely to be suitable for controlling a model. It is ok for car door locks and alarms, where 20-30 feet range is acceptable. Hope this helps. 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: KC CHAN [PDD] kcc...@hkpc.org To: EMC-PSTC Discussion Group emc-p...@ieee.org Sent: Wednesday, June 20, 2001 8:52 PM Subject: Radio controlled aircraft (toys) Another question about R/C toys, such as aircraft. Can we apply part 95 to this kind of products? --- 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: Let's not carried away (in a box)
Most of what was said below is true and I have to agree with the opinions expressed as well, but part needs serious critique. The part about exceeding RE limits and causing a problem to a non-radio receiver equipment is WRONG! No EMC engineer should make such a case! If you scale in from 1, 3, or 10 m to a much smaller distance (inches) the scaling is highly non-linear. And I don't mean it goes as r^n, either, with n = 1, 2, or 3. As you approach the emitting source (typically a cable) the field intensity is bounded by the rf common mode potential on the cable divided by its separation from ground, or the rf potential along its length at higher frequencies. That number will always be a few millivolts per meter, max. Further, with a culprit and victim cable laying adjacent, the coupled noise potential or current will always be less (on average) than the source potential/current. Another factor people forget is huge disparities in RE/RI test setups. The RI test set up illuminates a 1.5 m square. A culprit RE emitting cable adjacent to another cable can couple the whole parallel length, but as noted above, the coupling signal is tiny. An aperture or slot radiator a few inches away only illuminates a tiny portion of the 1.5 m square and coupling is proportional to the victim physical aperture illuminated. Finally, the RI signal is 80% AM at 1 kHz, which is much more severe than the typically cw or near cw clock-based unintentional emissions covered by RE limits. Moral: Exceeding RE limits does not correlate with interference to other than antenna-connected receivers. -- From: Whitehouse, Terence (Terry) twhiteho...@avaya.com To: 'Ken Javor' ken.ja...@emccompliance.com, emc-p...@majordomo.ieee.org, kyle_cr...@dell.com Subject: Let's not carried away (in a box) Date: Wed, Jun 20, 2001, 7:23 PM Let's not carried away (in a box - as an innocent victim of a catastrophic EMC event) is precisely Kyle's point. Originally, domestic and commercial EMC emissions standards were created to minimize broadcast reception interference. More recently, a much needed awareness on increasing the immunity of electronic systems to the massive amounts of EMC polution that exists in our increasingly complex society has thankfully made its way into the standards arena. Military and civil avionics are similarly regulated. Notwithstanding, international aviation regulatory authorities require management of personal electronics during critical phases of a commercial aircraft's flight. (I might ask is there really a non-critical aspect of flight when either accelerating down the runway, in flight at any height, or decelerating to a standstill?) Immunity standards define electric field stengths between 1 and 10 V/m. Clearly these levels are certainly far more severe than the fields created by a just compliant class B product at 3 meter separation; 40 dBuV versus 120 dBuV. Take into account a simple 10 dB distance compensation for a reduced 1 meter separation between a laptop and wiring harness installed under floor or overhead and add to it the 30 dB in excess of the limit as called out in this thread and the protection margin is significantly reduced. Is this a problem? Frankly, I don't know the answer. But it is my belief that our silence should not condone accepting a 30 dB error margin. A cell phone does intentionally emit at levels more closely approximating to the immunity thresholds. A waiting room sharing a wall with a consultation office might just provide a scenario where an instantaneous measurement could be recorded artificially high or low with a potentially disastrous outcome either way; preventative action not taken or mis-applied. I, for one, would not want to have my life put at risk by dependence on poorly enforced requirements such as notices or requests to turn off electronic emitters - be they intentional or unintentional. While 98% of the population acts responsibly, it is always the 2% who cause all of the problems with their selfish disregard for those around them. Cell phone anecdotes are plentiful. Ever been seated in an aircraft where the person in front of you reclines their seat immediately on take-off when the attendants can't notice? Is that laptop actually switched off? (Ever seen a loaded 18 wheel semi less than a car's length away at 65 mph?) Hmmm . (BTW, I really do enjoy flying and always try to get a good window seat to delight at the view below me. SFO to DFW routed over Southern Utah is awesome on a clear day!) Terry Whitehouse Avaya Regulatory Milpitas (408) 577-7714 -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Wednesday, June 20, 2001 8:43 AM To: kyle_cr...@dell.com; emc-p...@majordomo.ieee.org Subject: Re: FCC + FCC = FCC? - What? Let's not carried away. Those radiated emission limits protect broadcast radio reception, period. As such, your
Radio controlled aircraft (toys)
Another question about R/C toys, such as aircraft. Can we apply part 95 to this kind of products? --- 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: Hot Swappable Power Supplies ?
What's the accessibility to pins or traces or anything carrying hazardous energy when a power supply is pulled out? - Doug --- 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?
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,
Let's not carried away (in a box)
Let's not carried away (in a box - as an innocent victim of a catastrophic EMC event) is precisely Kyle's point. Originally, domestic and commercial EMC emissions standards were created to minimize broadcast reception interference. More recently, a much needed awareness on increasing the immunity of electronic systems to the massive amounts of EMC polution that exists in our increasingly complex society has thankfully made its way into the standards arena. Military and civil avionics are similarly regulated. Notwithstanding, international aviation regulatory authorities require management of personal electronics during critical phases of a commercial aircraft's flight. (I might ask is there really a non-critical aspect of flight when either accelerating down the runway, in flight at any height, or decelerating to a standstill?) Immunity standards define electric field stengths between 1 and 10 V/m. Clearly these levels are certainly far more severe than the fields created by a just compliant class B product at 3 meter separation; 40 dBuV versus 120 dBuV. Take into account a simple 10 dB distance compensation for a reduced 1 meter separation between a laptop and wiring harness installed under floor or overhead and add to it the 30 dB in excess of the limit as called out in this thread and the protection margin is significantly reduced. Is this a problem? Frankly, I don't know the answer. But it is my belief that our silence should not condone accepting a 30 dB error margin. A cell phone does intentionally emit at levels more closely approximating to the immunity thresholds. A waiting room sharing a wall with a consultation office might just provide a scenario where an instantaneous measurement could be recorded artificially high or low with a potentially disastrous outcome either way; preventative action not taken or mis-applied. I, for one, would not want to have my life put at risk by dependence on poorly enforced requirements such as notices or requests to turn off electronic emitters - be they intentional or unintentional. While 98% of the population acts responsibly, it is always the 2% who cause all of the problems with their selfish disregard for those around them. Cell phone anecdotes are plentiful. Ever been seated in an aircraft where the person in front of you reclines their seat immediately on take-off when the attendants can't notice? Is that laptop actually switched off? (Ever seen a loaded 18 wheel semi less than a car's length away at 65 mph?) Hmmm .. (BTW, I really do enjoy flying and always try to get a good window seat to delight at the view below me. SFO to DFW routed over Southern Utah is awesome on a clear day!) Terry Whitehouse Avaya Regulatory Milpitas (408) 577-7714 -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Wednesday, June 20, 2001 8:43 AM To: kyle_cr...@dell.com; emc-p...@majordomo.ieee.org Subject: Re: FCC + FCC = FCC? - What? Let's not carried away. Those radiated emission limits protect broadcast radio reception, period. As such, your personal electronics are turned off when aircraft safety requires glitch-free operation of its NAV systems. Hospitals already prohibit INTENTIONAL electromagnetic transmissions which can affect patient safety. -- From: kyle_cr...@dell.com To: emc-p...@majordomo.ieee.org Subject: RE: FCC + FCC = FCC? - What? Date: Wed, Jun 20, 2001, 8:28 AM I think the answer is that the FCC allows declared compliant devices to be sold in another unit WITHOUT testing. This has allowed PCs on the market with as much as 30dB over Class B limits. It was my understanding that testing always had to be done for the most common configurations of equipment as it is shipped. If this new PC card is going to be shipped in more than 50% of a given line of products I believe that line needs to pass testing with the PC card. The intent of the standards is to limit testing to configurations within reason. I am guessing that the only reason this PC card has been tested so far is because it is going to be used in a majority of at least one line of products. Based on this the product (a PC I take it) should pass emissions tests with the PC Card, or a different PC Card should be used. I have to say that it is frightening how flippantly some of my colleagues accept that PCs are being released into the market up to 30 dB over the limit. The limits are there for a reason, and it is machines such as these that can interfere with airplanes, hospital equipment and the like. Although it may make your job a little harder some days, I think the next time you are on a plane or having surgery you will be happy that a notebook or a cell phone doesn't cause a failure of those critical systems. Sincerely, Kyle Cross --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web
RE: Examples of EMC problems in the real world
Hey Gary, Check out Banana Skins in EMC Compliance Journal, too. http://www.compliance-club.com/archive1/archindex.html Dave Wilson Senior Compliance Engineer Alidian Networks Inc. tel: (408) 273 4787 fax: (408) 273 4800 -Original Message- From: Gary McInturff [mailto:gary.mcintu...@worldwidepackets.com] Sent: Wednesday, June 20, 2001 2:12 PM To: EMC-PSTC (E-mail) Subject:Examples of EMC problems in the real world There have been requests in the past on this forum for examples of real world events that were EMC related, as I recall we got a few but not many examples. In an email with Ralph he mentioned some work and an article that he had written chronically some of these problems. I asked him for some of his examples and he kindly sent the items below and has graciously allowed me to forward them. Thanks Ralph, and I hope that you enjoy them as much as I did. Gary -Original Message- From: Ralph Cameron [mailto:ral...@igs.net] Sent: Tuesday, June 19, 2001 6:14 PM To: Gary McInturff Subject: Some life threatening cases of EMI and others Gary: These cases were reviewed in an article I wrote about 14-15 years ago. Most incidents could happen tomorrow and came from a record of emi cases reported to all Canadian district offices of what used to be called Communications Canada. The reports covered a planned three month monitoring period during which time ther were 439 emi related reports and another 242 cases of swamping ( RF overload of TV, radio etc.) If you consider that Canadian incidents represented about 8% of the total number of incidents in the U.S. at that time, it may help to place the occurrences in perspective. Since that time, Industry Canada has not recorded domestic problems or complaints due to a lack of immunity ( radiated or conducted) but do have an advisory bulletin specifying field strengths communication transmitter owners cannot exceed. These limits are taken from the EU requirements for electronic equipment radiated immunity . Not surprisingly, I have found at least 95% of interference cases have been resolved not by increasing radiated immunity but, by reducing or eliminating most of the conducted component That's why I believe the simple expedient of designed in conducted immunity levels the playing field for all consumers and removes the nuisance of trying to find a solution, particularly, after sale. Examples: London Ont. A vhf broadcast radio link , owned by a commercial broadcast station , operating in a shopping mall, disrupted electronic weigh scale operation. False and incorrect weights and prices were displayed while the link was operating. Peterborough Ont. A CAT scan medical device's operation was disrupted by transmissions from a new FM broadcast transmitter. Brampton ON Radio frequency plastic sealing equipment located in close proximity to a neighbouring paint operation seized control of the six foot paddles stirring the vat of paint to the point where the shaft broke away from the motor , burst through a water tank and embedded itself in the factory wall. Toronto ON A hospital heart monitoring system displayed erroneous readings when the hospital radio despatch system was operated. Toronto ON A Federal government's computer system would crash when a nearby chiropractor operated his diathermy ( radio frequency generator ) machine. Edmonton Ab The telephone company lost billing data from their computer system which was attributed to the operation of a nearby private commercial radio despatch system. Calgary Ab An amateur radio operator's transmissions were heard in the recording equipment of a professional recording studio. Until the problem was resolved, the studio lost money on their operations. Grande Prairie Ab When a hospital's diathermy was used, the hospitl alert system would occasionally issue a a 'code 9' alert, in error. The diathermy also affected the physiotherapist's treadmill by accelerating the motor control mechanism. Grande Prairie Ab The mobile cranes on a logging company's railway had a collision avoidance system installed in each crane. Radio transmissions would occasionally defeat the protection offered by these systems. In Ottawa ON Ontario Hydro Electric Power Commission reported that Oil fired generating stations' control equipment on oil fired generators was affected by operation of nearby mobile radio equipment . Gas monitors, required for confined space atmosphere, continuous monitoring of toxic/ explosive gases and oxygen were found to give false alarms in 7 of 8 tested near UHF , narrowband ( 466Mhz ) transmissions and one had problems from 49Mhz narrow band signals. Because many amateur radio operators reside in urban areas, their HF operations ( covering 1.8-144Mhz ) have been demonstrated to affect the following . In some instances they could cause harmful effects: Intravenous pump in hosptial room went into the reset ( fail safe) mode
Re: FCC + FCC = FCC?
Re: FCC + FCC = FCC?Massey, Doug C. wrote: 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 ? I'd say no. I could make my own, which I've done, never test, and not be concerned. I'm not a mfr-ing location and the quantities are so low, it's not a real concern. - Doug --- 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,
EMC Safety - Perfect together??/
Hi Tania, Well I think the metric that should be used is the number of user safety related occurences of IT equipment..I'll bet the number is low.!! Having been involved in Safety for a couple of years I was struck by the different approaches that the compliance regulators adopted. To be fair the system level approach IS the correct approach for EMC - after all the final assembly is the mechanism that will radiate or be susceptible. However, the EMC industry is facing a crossroads. If the regulators continue to maintain the current methodology(like King Canute) inspite of the tsunami of electronic products, then I fear there is no future for the standards. After all there are many bright managers out there who will come to the conclusion that the emissions test is voided by the sheer volume of product that is released and the inability of mnufacturers to maintain the compliance without crippling cost and schedule. Chas Grasso --- 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: Products Electrical Ratings De-rated for Eurpoean Branch Circuits
Peter Tarver wrote in reply to my comment The rating of a UL rated fuse is more or less the current at which it blows. The rating of a fuse to IEC 127 (used throughout Europe) is more or less the working current of the fuse and the circuit it protects This may or may not be true. Last I looked, UL Listed miniature fuses (typically 1 X 1-1/4in cartridge size) and branch circuit protection fuses are required to carry 110% of their rated current for a minimum specified time and 100% continuously; Listed microfuses are required to carry 100% of current continuously. For a UL Recognized fuse (including 5 X 20mm cartridge sizes, of which you most likely refer), this is not necessarily the case, though it may be. Thus, the rating of a fuse ... is more or less the working current of the fuse is as true for a UL Listed fuse as it is for an IEC 127 fuse. For Recognized Component fuses, any deviation from the base requirements for Listing is rationale to allow only Recognition. These base requirements include, but are not limited to: physical dimensions, current carrying capacity, calibration or time-to-open characteristics, time delay characteristics for time delay rated fuses, etc. There is a substantial difference in the rating of UL and IEC127 fuses. UL listed fuses such as 1 x 1¼ in fuses are required to blow at 135% of rating in one hour. IEC127 fuses such as 5 x 20mm are required not to blow in one hour at 150% of rating. The difference in must blow and must not blow means that the actual current the fuses blow at is very much wider than the 135% to 150% ratio. The first must blow current mentioned in IEC127 is at 210% of rating. With fuses only sure to hold at 110% percent of rating you would not use a load with a nominal load of 100% of the circuit rating as small deviations upward of nominal may take out the fuse. That is why it is common to derate branch circuits in the US. This is not needed with IEC127 fuses. It is quite reasonable to have the nominal load equal to the rating of the protection. My characterisation of the two rating systems being blowing current and working current may be fairly crude but it is not that far from true I do not have the figures for circuit breakers to hand but I believe there is a similar disparity in European and US ratings. The current carrying rating of European wiring regulations obviously reflect these differences. If fact these differences might have something to do with the differences in the rating of IEC320 C13 C14 connectors in the US and Europe discussed in this forum recently, 15A in the US 10A in Europe. Peter further wrote One is left with the question: are fuses used throughout Europe as an integral part of mains circuit protection? By this I include the power supply cord as an extension of the mains, whether or not it is included by definition or is absolutely correct in everyone's perspective. There is certainly a move towards circuit breakers and away from fuses but fuse protection is still being used in new domestic premises and some industrial ones also and there is a huge installed base of fuse protected wiring. The latest issue of the UK wiring regulations have tried to push the move to circuit breakers by allowing smaller wire to be used in circuit breaker protected circuits of the same rating as fuse protected circuits to reflect the closer ratio of must break to must hold currents of circuit breakers. The UK ring main system is unusual if not unique. Because the ring main will be protected by a 30A or 50A fuse or breaker and the plugs and sockets on the ring rated at 13A (despite their vast size) and the power cord possibly rated considerably less than this, the fuses in BS1363 plugs used in the UK are an essential part of electrical safety in the UK. One is left with the question: are fuses used throughout Europe as an integral part of mains circuit protection? By this I include the power supply cord as an extension of the mains, whether or not it is included by definition or is absolutely correct in everyone's perspective. --- 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,
