Re: explanation of ESD events with coins in baggie.
George, I think your reasoning is convincing to me. Thanks. But please allow me to pose a silly question: Are we really sure those kinds of shaking coins interferences can be categorized as ESD (Electrostatic Discharge) problem? In your experience, for instance, the screw driver did not carry any electrostatic charge before striking the nickel surface. Right? We don't know if coins, keys, and metal door got electrostatic charged before jangling or slamming in Doug Mckean's experiences, either. ASSUMING friction and striking between different materials would cause fast electron transition between materials, back and forth, and then produce strong RF EM waves, there is no Electrostatics involved. If we are not sure whether or not those objects were electrostatic charged before friction, can we try to see if it makes difference? Best Regards, Barry Ma - Original Text From: George Tang gt...@convergenet.com, on 3/15/99 4:25 PM: Barry, No, I did not measure the 15kv on the scope, but I suspect that was the case. Here is my reasoning: The system was well shielded with aperture size smaller than 1/2 inch with few apertures. The system passed FCC B emi limits with 8 dB margin. It seemed very unlikely for a power plane in such a system to pick up 8 volts of radiated noise, since large power planes are not efficient antennas. And to charge the power and ground planes with many caps up to 8 volts at 100 MHz fundamental and GHz harmonics would seem to require very high power of radiated energy, assuming the lumped circuit model is used for the caps and planes at 100 MHz. But on the other hand, the boards are grounded to the chassis, so if the chassis had ESD noise of many kv conducted to it, it could generate 8 volts on the power to ground plane. The chassis is low impedance, so high current noise is likely. With radiated noise, even at near field, the propagation impedance would still be higher than conducted, so high current noise seemed more unlikely. The system had already passed 15kv ESD air (and accidental contact discharge) on most all parts on the chassis, then the screw driver noise maybe higher than 15 kv conducted ESD. You can see there are many assumptions used. But trying to measure the screw driver to chassis ESD voltages directly with differential probes is difficult because a large current loop formed by the probes is required due to the moving parts and the probes may be damaged by the ESD. I did not measure the screw driver voltage, but I guessed that it was high voltage/current conducted ESD that caused the system error. Hope that helps. George Tang (Bailin Ma) wrote: George, You mentioned: the ESD generated by the metal surface was much higher than 15kv. at the end of your note. Does that mean you measured the noise between power and ground planes using digital scope, and got the higher than 15 KV reading on the scope when striking a screw driver against the nickel plated surface? Thank you. Barry Ma Anritsu Company Morgan Hill, CA 95037 - Original Text From: George Tang gt...@convergenet.com, on 3/15/99 1:23 PM: Douglas, I have seen similar events in a different way. Years ago, I helped design an electronic system using plastic chassis with nickel surface plating. The system passed 15kv ESD air discharge and 8kv contact. But in the hardware lab, the system gets data error everytime a piece of metal (like a screw driver) is striked against the nickel plated surface on chassis. A digital scope is used to measure the noise generated on power and ground planes on the PCB inside the chassis and the scope captured a noise voltage as high as 8 volts peak to peak on the PCB from a few hundred MHz to beyond GHz. The PCB was very well decoupled with power next to ground planes and many on board capacitors. This puzzled me at first. But I remembered a very knowledgeable mechanical engineer once told me to never use nickel material in an application where friction takes place. Nickel has a very hard and rough surface, so in a frictional application, it always damages the mating surface. Maybe this explains the events that you saw, and the ESD generated by the metal surface was much higher than 15kv. Regards, George Tang Douglas McKean wrote: Hans, That's certainly an interesting explanation, but does not correlate to at least three different scenarios. 1) A calibrated ESD simulator in self discharge mode at 15KV. When the results of the ESD simulator are compared to the results of the coins, the coins have a fairly wideband constant level from 0 - 2 GHz. Both start off at roughly the same level with the only the coins remaining constant throughout. The ESD simulator has approx a -20dB per octave drop off. A side interest is that on the display of the SA has an IF overload indication. This tells me that the
RE: EN 61326
Dear Laura, Yes, you are correct. You must start the test at the zero cross points (0 and 180). Best regards, Tetsuya Hashimoto A-pex International Co.,Ltd. 2nd EMC Division Yokowa Lab E-mail: has...@a-pex.co.jp Hello Everyone, While reviewing the new EN 61326 standard I noticed that the test value for AC power voltage dip/short interruptions (IEC 61000-4-11) is 0.5 cycle, each polarity/100%. I understand the 0.5 cycle and the 100%, the question that I have is with each polarity. I am assuming that each polarity means 90ｰ phase and 270ｰ phase. I would appreciate any comments on whether or not I am interpreting the test value correctly. Thank you in advance for your help, Laura Newton - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: explanation of ESD events with coins in baggie.
Do you get the same effect with the coins in a cloth bag or a paper bag? Has anybody tried it? Lou At 10:57 AM 3/15/99 -0600, you wrote: Douglas, I have seen similar events in a different way. Years ago, I helped design an electronic system using plastic chassis with nickel surface plating. The system passed 15kv ESD air discharge and 8kv contact. But in the hardware lab, the system gets data error everytime a piece of metal (like a screw driver) is striked against the nickel plated surface on chassis. A digital scope is used to measure the noise generated on power and ground planes on the PCB inside the chassis and the scope captured a noise voltage as high as 8 volts peak to peak on the PCB from a few hundred MHz to beyond GHz. The PCB was very well decoupled with power next to ground planes and many on board capacitors. This puzzled me at first. But I remembered a very knowledgeable mechanical engineer once told me to never use nickel material in an application where friction takes place. Nickel has a very hard and rough surface, so in a frictional application, it always damages the mating surface. Maybe this explains the events that you saw, and the ESD generated by the metal surface was much higher than 15kv. Regards, George Tang Douglas McKean wrote: Hans, That's certainly an interesting explanation, but does not correlate to at least three different scenarios. 1) A calibrated ESD simulator in self discharge mode at 15KV. When the results of the ESD simulator are compared to the results of the coins, the coins have a fairly wideband constant level from 0 - 2 GHz. Both start off at roughly the same level with the only the coins remaining constant throughout. The ESD simulator has approx a -20dB per octave drop off. A side interest is that on the display of the SA has an IF overload indication. This tells me that the transients from the coins are quite possibly a lot higher and much quicker than what the SA can handle within the sampling window. 2) The level from the coins is proportional to the dissimilarity of the metals of the coins. A bag of quarters has a lower profile than a bag of quarters and pennies. Thus, there is some function due to electronegativity differentials. Actually, a significant amount of difference. 3) I can cause the same effect by sliding the coins back and forth as a group within the bag. Thus, the coins are in at least incidental contact with each other so that differing potentials amongst the coins is minor. I'm not sure if anyone knows the reason. Regards, Doug McKean At 11:11 AM 3/11/99 -0800, Hans Mellberg wrote: There is an expanation for this seemingly unlikely event. Having coins in a baggie and jingeling them causes the following events to occur: The rubbing of a coin against the polymer causes triboelectric charging of both the coin and localized areas of the bag. Since there are multiple coins, each coin will charge at some voltage level but not necessarily the same as another coin. When two coins of different charged voltages come within dielectric breakdown distances, a discharge will occur from one coin to the other in order to equalize the charge distribution (q1=C1V1 and q2=C2V2. When they touch, the new q1 will be C1V3 and q2= C2V3 where V3=(q1+q2)/(C1+C2)). Since coins are electrically small with very small capacitances, the expected discharge waveform has a very fast risetime hence the radiation at the GHz region. There will also be discharges from the localized charged areas of the polymer to coins of different voltages. While separating two charged surfaces from each other, the voltage rises significantly since the capacitance is being reduced and the conservation of charge must be preserved which is the basis for tribolectric voltage generation. Hope that helps Hans Mellberg ---b...@namg.us.anritsu.com wrote: Hi Douglas, What you described is very interesting! But I cannot understand Jingling change in a ziplock bag produces very high levels of super fast transients up into the GHz range. It seems to me that jingling coins, jangling keys, and slamming metal door would certainly produce acoustic waves. How come they also produced electromagnetic waves? If do, under what conditions? What is the mechanism to produce very high level of transient EM waves? Did that company incorporate those kinds of Jingling change in a ziplock bag tests into regular ESD tests for their thereafter products? What is the lessen we all should learn from this particular example? Hopefully you don't think it's offensive to ask above questions. I am just very curious. Thank you. Best Regards, Barry Ma (408)778-2000 x 4465 - Original Text From: Douglas McKean dmck...@corp.auspex.com, on 3/10/99 2:55 PM: At 08:03 AM 3/8/99 PST, Bailin Ma wrote: Hi
Fw: EN 50021 and the EX Mark
Posted for Carl Newton cwnew...@xycom.com: From: cnew...@xycom.com Subject: EN 50021 and the EX Mark Date: Mon, 15 Mar 1999 15:26:53 -0500 To: emc-p...@majordomo.ieee.org Regarding Zone 2 Hazardous Locations compliance in the EU: My understanding is that no harmonized standards have been listed in the Journal, and that the proposed EX Mark is still meaningless. I've found an industrial product with the EX mark on it. It's been a few years since I've studied this matter, but I believe that certification to a standard such as EN 50021 must still be done in each EU member nation. Anyone up to date on this issue? Thanks in advance, Carl ---End of Original Message- -- Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: emc-pstc@listserv.ieee.org Date: 03/15/1999 Time: 15:18:33 -- - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Argentina's Resolution 92
UL has informed me that they have signed a MOU with IRAM. IRAM will accept test results from UL where UL has demonstrated experience with IEC standards, such as IEC 950. IRAM will even issue their mark based upon those tests. As an option for Phase II only, IRAM will accept products that bear the UL Listing Mark if the Argentine deviations have been taken into consideration during the evaluation (operating voltage and power cord, for example) For additional information contact Willie Janisch at janis...@ul.com mailto:janis...@ul.com . -- From: WOODS, RICHARD Sent: Tuesday, March 09, 1999 1:51 PM To: 'emc-pstc' Subject: Argentina's Resolution 92 Per Resolution 92, Argentina was scheduled to require a Conformity-to-Type Certificate for electronic apparatus effective 18 June, 1999. The problem, of course, was that when the resolution was published they did not have the infrastructure nor MRAs in place to accomplish this task. Has anyone heard of any change in their capabilities to test, MRAs with other agencies, or a change in the date? - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Looking for a filter
I have a low frequency control port that has a high frequency (300 MHz) common mode harmonic noise on all three lines. This is on an existing card with a limited amount of real-estate available. To compound the problems I am driving a unique, off-the-shelf, device with no provisions for proper shielding. As such, I am looking for a filtered 3 pin mini-din connector, or a filter assembly that would lend itself to surface mounting. Any suggestions? Thanks Rick Busche rbus...@es.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: explanation of ESD events with coins in baggie.
We might have to correct a misconception of triboeletrification that we learnt from all demonstrations in schools. The myth is triboeletrification only happens to insulators. Can we try to say: Triboeletrification would cause transfer of electrons between different materials. Insulators would hold electrostatic charges due to the triboeletrification. On the other hand, transient flow of electrons between different metals would produce broadband EMI. Please correct me. Thank you. Barry Ma - Original Text From: r...@twn.tuv.com, on 3/16/99 12:16 PM: I remember a similar effect. Many years ago, when I was a student, in my room I had a TV set with a simple loop antenna. 2 meters away from the antenna was the radiator of the central heating of that house. On seams of the elements of that radiator the paint had come off. Below the paint the metal was slightly oxidized with a black colour. When I took a scewdriver and rubbed the metal blade along that seam the TV picture would become distorted with some black lines. I always wondered why, and in fact still do. Rene Charton - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
UL/CSA Listings (a Clarification)
Hello All, Just had a short emailversation with Dick Pittenger regarding his response (enclosed below). We both agreed that while his response may be true in the Consumer Product world, it is not correct with respect to the Workplace (under OSHA's control); And that happens to be where Mr. Harlowe's equipment is headed for (as determined in an emailversation with Mr. Harlowe earlier today). OSHA requires all electrical equipment to be Listed, Labelled, etc, per the earlier and very comprehensive response on this topic submitted by Ron Pickard. Regards, Art Michael Int'l Product Safety News A.E. Michael, Editor P.O. Box 1561 PSTC Middletown CT 06457-8061 U.S.A. Phone : (860) 344-1651 Fax: (860) 346-9066 Email : i...@connix.com Website: http://www.safetylink.com ISSN : 1040-7529 * * * * * * * * * * * * * * * * * * * * * * * International Product Safety Bookshop * * Check out our current offerings! * * http://www.safetylink.com/bookshop.html * * A new service of the Safety Link * * * * * * * * * * * * * * * * * * * * * * * - -- Forwarded message -- List-Post: emc-pstc@listserv.ieee.org Date: Tue, 16 Mar 1999 13:44:06 -0500 From: pitt...@pmifeg.com To: emc-p...@ieee.org Hello Brian: Concerning your questions about the requirement for UL Listing/CSA Certification for electrical equipment used in the USA and Canada, here's my two cent's worth (this is based on 20+ years of handling submittals to both agencies): For the USA, NFPA 70 (the National Electrical Code) makes reference to use of Listed equipment, meaning that electrical construction equipment, conduit, outlets, boxes, circuit breakers AND utilization equipment such as appliances which are permanently connected to the branch circuit, must be evaluated and covered by an NRTL such as UL. Thus, any installation that will be subjected to an electrical inspection needs to be made-up of Listed equipment. If not, the inspector performing the inspection must make the judgment himself concerning suitability of the components. Some states and cities are not willing to take on that responsibility and make it very difficult to use non-Listed equipment. Field inspections by UL are possible but cost-prohibitive. For cord-connected portable equipment, it is entirely possible to avoid any Listing at all since the user simply takes the product home and plugs it in with no electrical inspection taking place. Case in point is holiday lighting strands, many of which are on store shelves with no Listing Marks in evidence. In reality, most reputable manufacturers want, and in-the-know consumers demand, a third-party Listing of some sort. Personally, I wouldn't want any electrical product in my home that didn't meet at least such minimum levels of safety standards such as UL's (indeed some of the products that do have the Mark are marhinal at best).. Additionally, with the product liability climate in the USA, manufacturers want the extra assurance that an outside organization has agreed that a minimum safety standard has been met. This can be very beneficial during litigation. For Canada, Certifications or field inspections of electrical equipment are mandated by law. Therefore, in most instances, a Certification is the most economical procedure. For low-volume equipment, field inspections are possible but again expensive. Note that it's very common now for manufacturers to submit to UL or CSA for coverage in both the USA and Canada-one project for a small additional expense covers requirements for both and allows for markings acceptable to both countries to be placed on each unit. Hope this information helps some. R. Pittenger PMI Food Equipment Group Troy, Ohio - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
[no subject]
Hello Brian: Concerning your questions about the requirement for UL Listing/CSA Certification for electrical equipment used in the USA and Canada, here's my two cent's worth (this is based on 20+ years of handling submittals to both agencies): For the USA, NFPA 70 (the National Electrical Code) makes reference to use of Listed equipment, meaning that electrical construction equipment, conduit, outlets, boxes, circuit breakers AND utilization equipment such as appliances which are permanently connected to the branch circuit, must be evaluated and covered by an NRTL such as UL. Thus, any installation that will be subjected to an electrical inspection needs to be made-up of Listed equipment. If not, the inspector performing the inspection must make the judgment himself concerning suitability of the components. Some states and cities are not willing to take on that responsibility and make it very difficult to use non-Listed equipment. Field inspections by UL are possible but cost-prohibitive. For cord-connected portable equipment, it is entirely possible to avoid any Listing at all since the user simply takes the product home and plugs it in with no electrical inspection taking place. Case in point is holiday lighting strands, many of which are on store shelves with no Listing Marks in evidence. In reality, most reputable manufacturers want, and in-the-know consumers demand, a third-party Listing of some sort. Personally, I wouldn't want any electrical product in my home that didn't meet at least such minimum levels of safety standards such as UL's (indeed some of the products that do have the Mark are marhinal at best). Additionally, with the product liability climate in the USA, manufacturers want the extra assurance that an outside organization has agreed that a minimum safety standard has been met. This can be very beneficial during litigation. For Canada, Certifications or field inspections of electrical equipment are mandated by law. Therefore, in most instances, a Certification is the most economical procedure. For low-volume equipment, field inspections are possible but again expensive. Note that it's very common now for manufacturers to submit to UL or CSA for coverage in both the USA and Canada-one project for a small additional expense covers requirements for both and allows for markings acceptable to both countries to be placed on each unit. Hope this information helps some. R. Pittenger PMI Food Equipment Group Troy, Ohio - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: UL/CSA Listings
Hi Brian, Whizzy, eh? Well, I think that most of us resemble that remark. :-) First, UL and CSA are but two of the 17 NRTLs that are accredited by the Occupational Safety and Health Adminstration (OSHA) which is a part of the US Department of Labor. Anyway, according to OSHA regulations (29CFR Subpart 1910.399), an installation or equipment is acceptable to the Assistant Secretary of Labor, and approved within the meaning of this Subpart S: (i) If it is accepted, or certified, or listed, or labeled, or otherwise determined to be safe by a nationally recognized testing laboratory; or (ii) With respect to an installation or equipment of a kind which no nationally recognized testing laboratory accepts, certifies, lists, labels, or determines to be safe, if it is inspected or tested by another Federal agency, or by a State, municipal, or other local authority responsible for enforcing occupational safety provisions of the National Electrical Code, and found in compliance with the provisions of the National Electrical Code as applied in this subpart; or (iii) With respect to custom-made equipment or related installations which are designed, fabricated for, and intended for use by a particular customer, if it is determined to be safe for its intended use by its manufacturer on the basis of test data which the employer keeps and makes available for inspection to the Assistant Secretary and his authorized representatives. Refer to 1910.7 for definition of nationally recognized testing laboratory. The meaning of accepted as it applies here is An installation is accepted if it has been inspected and found by a nationally recognized testing laboratory to conform to specified plans or to procedures of applicable codes. What this means is that equipment bound for use in the US or its territories must either be formally tested by a NRTL, or be subject to the requirements of the National Electrical Code (NEC) on a case-by-case basis. However, due to the lack of technical expertise on the part of the NEC inspectors, they can, and do, refer an evaluation back to the NRTLs. This is the essense of the NRTL's field inspection and labeling programs. Well, that's it in a nutshell. Any additional comments from any of us whizzies? I hope this helps to answer your question. Best regards, Ron Pickard ron_pick...@hypercom.com __ Reply Separator _ Subject: UL/CSA Listings Author: Brian Harlowe bharl...@vgscientific.com at INTERNET List-Post: emc-pstc@listserv.ieee.org Date:3/16/99 12:14 PM Hi Everybody Can some of you Whizzy American Engineers provide me with some information. The word on this side of the Atlantic is that if Equipment is not UL/CSA approved. It MUST be field labelled. Can anyone confirm this please Regards Brian Harlowe * opinions expressed here are personal and in no way reflect the position of VG ientific - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Notebook computers for Emi testing
Hello All, I am about to purchase a notebook (support equip.) computer for use in Emi / immunity testing of our (ITE) equipment. I have no experience with notebooks (in Emi testing) and am looking for your opinions on which manufacturer(s) are quiet performers for this application. Thank You, George Sparacino - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: explanation of ESD events with coins in baggie.
---Lou Gnecco l...@tempest-inc.com wrote: Do you get the same effect with the coins in a cloth bag or a paper bag? Has anybody tried it? Lou To answer that, there are two parts; 1) Look at the triboelectric series chart. This chart, shows, what materials when rubbed with what other materials, will generate either a positive or negative charge and the relative magnitude of the charge. The materials at the top of the chart will generate a positive charge and the materials at the bottom of the chart will generate a negative charge. The farther apart the materials, the greater the charge build up. 2) Determine the conductivity of both materials. If one of the materials is a conductor, then assume that dishcharge can occur from any location. If it is an insulator, then a dicharge can only occur from the localized charged area. If one of the materials is a conductor and the second material is poor conductor such as paper or cloth, then the charge will begin decaying as soon as it is built up with a time constant based on the conductivity of the poor conductor. So, to answer your question, paper or cloth bags will have a lesser effect than a polymer bag. In certain conditions, the charge may not even built up enough to create any effects. Hans Mellberg _ DO YOU YAHOO!? Get your free @yahoo.com address at http://mail.yahoo.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Invitation to EU workshop for all CABs (Washington, D.C., Apr il 2 7-29)
According to this site, the MRA process is being delayed. http://www.cix.co.uk/~approval/n2_0199.htm http://www.cix.co.uk/~approval/n2_0199.htm -- From: Leafloor, Bob: DSI [SMTP:leafloor@ic.gc.ca] Sent: Tuesday, March 16, 1999 8:11 AM To: t...@world.std.com Subject: RE: Invitation to EU workshop for all CABs (Washington, D.C., Apr il 2 7-29) For US registration contact: jogindar.dhil...@nist.gov -Original Message- From: Scott Lemon [mailto:lem...@nortelnetworks.com] Sent: March 15, 1999 12:08 PM To: t...@world.std.com Subject: RE: Invitation to EU workshop for all CABs (Washington, D.C., Apr il 2 7-29) Sounds interesting - anyone know where to go for more details on registration, etc. (not obvious where to look once you are on DoC web page)? Regards, Scott Lemon (esn 351-4487, 919-991-4487) Fax: (919) 991-8724 Network Dependability Nortel Networks RTP, NC -Original Message- From: Victor L. Boersma [SMTP:vboer...@compuserve.com] Sent: Saturday, March 13, 1999 12:01 PM To: TREG Subject: Invitation to EU workshop for all CABs (Washington, D.C., April 2 7-29) For those who prefer to stop guessing and would like to get some information from the horse's mouthes: There will be two consecutive workshops, to be held in Washington, D.C. on April 27-29, 1999. On Tuesday, April 27, representatives of the European Commission, and other European experts, will brief interested parties from both the United States and Canada on responsibilities under relevant European directives (98/13/EC and 89/336/EEC) and the respective Canadian and US MRAs with the EU. A draft agenda for this all-day workshop is enclosed. Attendees are advised to bring copies of the relevant EU directives and the EU MRA with them to the workshop. On Wednesday, April 28, the National Institute of Standards and Technology (NIST) invites interested parties, including Canadians, to attend a workshop to develop the following two sets of criteria, for implementation purposes: (1) criteria for a sub-program under the National Voluntary Conformity Assessment Systems Evaluation (NVCASE) Program to satisfy product testing, certification and quality systems requirements of the telecommunications equipment and EMC annexes of the US/EC MRA; (2) criteria for the qualification and operation of telecommunications certification bodies (TCBs) under the FCC Report and Order 98-338 of 17 December 1998. The Tuesday and Wednesday workshops will be held from 9:00 a.m. - 5:00 p.m. in the Department of Commerce Auditorium, at 14th Street and Constitution Ave., NW, Washington, D.C. (Note: there also is a workshop on Thursday, doing much the same thing for the Canada - Switzerland MRA, in the Canadian Embassy in Washington. Since the US has no MRA with Switzerland (yet) this may be of interest only to Canadians). You must pre-register to attend any of the workshops by providing the full names and affiliations of planned participants from your organization by April 16, so that appropriate arrangements can be made. Note: I don't know where US attendees must register. Check with DoC or NIST. EU Workshop for North American CABs A.M. Overview of Practical Implementation of the MRA Transition Period (EMC and telecom/radio): - Manufacturer Responsibilities - Role of CABs - Competent Bodies' Role (EMC) - Notified Bodies' Role - both EMC and TTE - Annexes I - IV of the TTE Directive (98/13/EC) - Exchange of Test Reports, Etc. during the Transition Period - Confidence Building P.M. Overview of the Proposed RTTE Directive: - Description of the provisions of the directive - Essential requirements - Role of voluntary standards; shift from CTRs to TBRs or other ETSI standards, etc. - Availability of network technical information - Role of notified bodies - Need for quality systems The week following, ICC has arranged for a seminar and workhops that will allow for further elaboration, including full discussion on the new RTTE Directive that will replace the TTE Directive covered under the MRAs. This will provide you with valuable insights into where
CSZ.. service contact
Hello Group, Sorry to bother you with this one, but I am having a bit of a problem connecting with a service person for Cincinnati Sub-Zero. My tech has placed several calls and was told that someone would get back to us.. but it's been over a week.. we're still trying and still no call back. The unit is still under it's 2-year warrantee, so we don't want to pay an outside contract repair service if we don't have to. Does anyone have a specific name and phone number of a CSZ service person? Thanx for your help, George Sparacino - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Fw: EN 50021 and the EX Mark
The explosive atmospheres directive (ATEX) 94/9/EC is in force, but not mandatory until 30 June 2003. You are correct in stating that there are no standards published in the OJ yet, but that will occur soon. Also, prEN 50 021 is due to be published any day now as EN 50 021. By 'EX', I assume you refer to the 'Epsilon x within a hex' mark. This mark was also required under the old approach directive 76/117/EC, so based on the presence of that mark alone, you cannot tell whether the Certificate is to 76/117/EEC or 94/9/EC, you must look to the particular type of CE marking outlined in the ATEX directive. Yes, there are ATEX Certificates issued that are based on prEN 50 021, this is permitted by the directive. Under 76/117/EEC, there were no standards for Zone 2 locations, so the only option for Zone 2 was to obtain a National Certificate in each member state. The standard most frequently used was BS 6941:1988. Under ATEX, this is no longer true as the directive applies to Zone 0, 1, and 2 hazardous areas. Certification is not required for Zone 2 apparatus, self declaration may be used. If you have any further questions, please contact me privately. Bill Lawrence Factory Mutual 781-255-4822 william.lawre...@factory-mutual.com At 15:18 3/15/1999 -0800, ed.pr...@cubic.com wrote: Posted for Carl Newton cwnew...@xycom.com: From: cnew...@xycom.com Subject: EN 50021 and the EX Mark Date: Mon, 15 Mar 1999 15:26:53 -0500 To: emc-p...@majordomo.ieee.org Regarding Zone 2 Hazardous Locations compliance in the EU: My understanding is that no harmonized standards have been listed in the Journal, and that the proposed EX Mark is still meaningless. I've found an industrial product with the EX mark on it. It's been a few years since I've studied this matter, but I believe that certification to a standard such as EN 50021 must still be done in each EU member nation. Anyone up to date on this issue? Thanks in advance, Carl ---End of Original Message- -- Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 Date: 03/15/1999 Time: 15:18:33 -- - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). Bill Lawrence South Yarmouth, MA 02664 wlawr...@capecod.net - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
UL/CSA Listings
Hi Everybody Can some of you Whizzy American Engineers provide me with some information. The word on this side of the Atlantic is that if Equipment is not UL/CSA approved. It MUST be field labelled. Can anyone confirm this please Regards Brian Harlowe * opinions expressed here are personal and in no way reflect the position of VG Scientific - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: explanation of ESD events with coins in baggie.
I remember a similar effect. Many years ago, when I was a student, in my room I had a TV set with a simple loop antenna. 2 meters away from the antenna was the radiator of the central heating of that house. On seams of the elements of that radiator the paint had come off. Below the paint the metal was slightly oxidized with a black colour. When I took a scewdriver and rubbed the metal blade along that seam the TV picture would become distorted with some black lines. I always wondered why, and in fact still do. Rene Charton - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: Earth Bonding Requirements for Telecom Equipment
Regards, Gert Gremmen Ing. == Ce-test, Qualified testing == Consultants in EMC, Electrical safety and Telecommunication Compliance tests for European standards and ce-marking Member of NEC/IEC voting committee for EMC. Our Web presence: http://www.cetest.nl List of current harmonized standards http://www.cetest.nl/emc-harm.htm 15 great tips for the EMC-designer http://www.cetest.nl/features01.htm -Original Message- From: Ing. Gert Gremmen [mailto:cet...@cetest.nl] Sent: maandag 15 maart 1999 19:35 To: Peter Merguerian Subject:RE: Earth Bonding Requirements for Telecom Equipment Importance: High Hello Peter, I am not familiar with your bullet type wire termination, at least not under that name, so i cannot share my experience with these. About the termination of earth wires; no i know that it's no good practice and it is therefore not allowed in 950. You better bond the two together on a separate bonding terminal and then lead one wire to your 5-pole connector. Even better for reliability is two 3-pole connectors. The main problem with 2 wires in one (crimp) type of connector is that if one of the 2 supply wires is pulled away by brute force, that the other wire goes with it, or if it's not, its connection quality is reduced below acceptable. This certainly reduces the quality of your design, where you used a second redundant supply cable for reliability reasons, you invalid it's redundancy by connecting the two together. I certainly disagree using a shield for safety. One might conclude that shielding is superfluous and replace by unshielded, thereby invalidating the safety concept. Only one solution is acceptable : the right one ;). In general: safety measures should be visible, and clearly distinguishable from functional circuits, and should never be hidden as a functional circuit. visible : for inspection in manufacturing and quality control clearly as such : so no one in the field might be tempted to replace a unclear measure by a less reliable equivalent Regards, Gert Gremmen Ing. == Ce-test, Qualified testing == Consultants in EMC, Electrical safety and Telecommunication Compliance tests for European standards and ce-marking Member of NEC/IEC voting committee for EMC. Our Web presence: http://www.cetest.nl List of current harmonized standards http://www.cetest.nl/emc-harm.htm 15 great tips for the EMC-designer http://www.cetest.nl/features01.htm -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Peter Merguerian Sent: zondag 14 maart 1999 21:57 To: 'EMC-PST'; t...@world.std.com Subject:Earth Bonding Requirements for Telecom Equipment Dear All, A telecom rack subsystem has two power entry modules (for redundancy); two cables, one for each power entry module, each consisting of 3 leads (+, - and earth), are terminated by means of a 3-pole connector to each power entry module; the other end of the cables are terminated to one 5-pole connector where two of the earthing leads are terminated together in one terminal of the connector and the other four leads (supply) are terminated to each of the remaining terminals of the connector. This 5-pole connnector is the connection to the power distribution unit which has the main earthing terminal, power supply connections and circuit breakers. 1. Do you see a problem with UL1950/EN 60950 of terminating two earth bonding leads to one terminal? I should state that the connector is Recognized but most likely evaluated to accept one wire per terminal. 2. Assuming that the combination of connector and two leads in one terminal was submitted for a separate investigation (to one of the connector standards), is there some clause in the standard which will not allow me to use this type of termination? 3. In lieu of 3 leads/cable, can manufacturer use 2 leads/cable and use the shield of the cable as the earth bonding conductor? 4. For wire terminations in general, I find that more and more manufacturers like (for manufacturing reasons) to terminate their leads to insulated bullet type pressure terminal connectors prior to terminating them to connectors and/or terminal blocks employing pressure wire terminals. However, even though the connectors/terminal blocks are Recognized, these bullet type connectors are not Approved. Is anyone using the same technique in manufacturing? If so, do you use Listed and/or Recognized bullet-type pressure wire connectors? If so, can you supply with some manufacturer's names of such connectors? Thanks in Advance, PETER S. MERGUERIAN MANAGING DIRECTOR PRODUCT TESTING DIVISION I.T.L. (PRODUCT TESTING) LTD. HACHAROSHET 26, P.O.B. 211 OR YEHUDA 60251, ISRAEL TEL: 972-3-5339022 FAX: 972-3-5339019 E-MAIL: pe...@itl.co.il Visit our Website: http://www.itl.co.il - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with
RE: passive loudspeakers
Chris, about safety, if you look at EN 60065 (IEC 60065), you'll see that any loudspeaker is included, regardless of its input voltage. Of course, most of the tests are not applicable to those devices. However, only loudspeakers using voltage higher than 50 V AC or 75 V DC are affected by LVD. It doesn't matter if it is a passive or active loudspeaker. Moreover, in order to test a loudspeaker, the laboratory needs an amplifier capable to provide the maximum power the loudspeaker admits. That amplifier is not under test, it is just an auxiliary equipment. I hope to have helped you Juan Pedro Peña CENTRO DE TECNOLOGIA DE LAS COMUNICACIONES, S.A. PTA - C/ Severo Ochoa, 2 - 29590 Campanillas (Malaga) - SPAIN Tel.: +34 95 261 91 55 - Fax: +34 95 261 91 13 e-mail: jpp...@cetecom.es Web: http://www.cetecom.es/ -- De: Colgan, Chris[SMTP:chris.col...@tagmclarenaudio.com] Enviado el: viernes 12 de marzo de 1999 13:13 Para: EMC-PTSC discussion group (E-mail) Asunto: passive loudspeakers Hello All Does anybody know of any safety or EMC regulations that apply to passive loudspeakers? Two particular areas of concern have been raised by colleagues: 1) Stability tests, especially for North America (or anywhere else) 2) Insulation of terminals - I have heard claims that as a loudspeaker could be supplied with a fairly large voltage, 100V rms or more, it could fall in to the scope of the Low Voltage Directive. I don't agree, but has anyone had any experience of this? Thanks Chris Colgan EMC Safety TAG McLaren Audio Ltd mailto:chris.col...@tagmclarenaudio.com = Authorised on 03/12/99 at 12:13:44; code 36dd0c74B2250754. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: explanation of ESD events with coins in baggie.
Barry, Your question is very much justified. I use the word ESD because in my mind, I play the image of the striking screw driver in slow motion. If you imagine the nickel surface robs the screw driver of its electrons to charge up the screw driver, then the electric field builds up as the screw driver moves away from the nickel surface to the point to cause air break down and screw driver discharge. In slow motion, this is exactly the ESD process. But in real-time, this is RF. Different perspective makes worlds of differences. :) Thanks, George Tang (Bailin Ma) wrote: George, I think your reasoning is convincing to me. Thanks. But please allow me to pose a silly question: Are we really sure those kinds of shaking coins interferences can be categorized as ESD (Electrostatic Discharge) problem? In your experience, for instance, the screw driver did not carry any electrostatic charge before striking the nickel surface. Right? We don't know if coins, keys, and metal door got electrostatic charged before jangling or slamming in Doug Mckean's experiences, either. ASSUMING friction and striking between different materials would cause fast electron transition between materials, back and forth, and then produce strong RF EM waves, there is no Electrostatics involved. If we are not sure whether or not those objects were electrostatic charged before friction, can we try to see if it makes difference? Best Regards, Barry Ma - Original Text From: George Tang gt...@convergenet.com, on 3/15/99 4:25 PM: Barry, No, I did not measure the 15kv on the scope, but I suspect that was the case. Here is my reasoning: The system was well shielded with aperture size smaller than 1/2 inch with few apertures. The system passed FCC B emi limits with 8 dB margin. It seemed very unlikely for a power plane in such a system to pick up 8 volts of radiated noise, since large power planes are not efficient antennas. And to charge the power and ground planes with many caps up to 8 volts at 100 MHz fundamental and GHz harmonics would seem to require very high power of radiated energy, assuming the lumped circuit model is used for the caps and planes at 100 MHz. But on the other hand, the boards are grounded to the chassis, so if the chassis had ESD noise of many kv conducted to it, it could generate 8 volts on the power to ground plane. The chassis is low impedance, so high current noise is likely. With radiated noise, even at near field, the propagation impedance would still be higher than conducted, so high current noise seemed more unlikely. The system had already passed 15kv ESD air (and accidental contact discharge) on most all parts on the chassis, then the screw driver noise maybe higher than 15 kv conducted ESD. You can see there are many assumptions used. But trying to measure the screw driver to chassis ESD voltages directly with differential probes is difficult because a large current loop formed by the probes is required due to the moving parts and the probes may be damaged by the ESD. I did not measure the screw driver voltage, but I guessed that it was high voltage/current conducted ESD that caused the system error. Hope that helps. George Tang (Bailin Ma) wrote: George, You mentioned: the ESD generated by the metal surface was much higher than 15kv. at the end of your note. Does that mean you measured the noise between power and ground planes using digital scope, and got the higher than 15 KV reading on the scope when striking a screw driver against the nickel plated surface? Thank you. Barry Ma Anritsu Company Morgan Hill, CA 95037 - Original Text From: George Tang gt...@convergenet.com, on 3/15/99 1:23 PM: Douglas, I have seen similar events in a different way. Years ago, I helped design an electronic system using plastic chassis with nickel surface plating. The system passed 15kv ESD air discharge and 8kv contact. But in the hardware lab, the system gets data error everytime a piece of metal (like a screw driver) is striked against the nickel plated surface on chassis. A digital scope is used to measure the noise generated on power and ground planes on the PCB inside the chassis and the scope captured a noise voltage as high as 8 volts peak to peak on the PCB from a few hundred MHz to beyond GHz. The PCB was very well decoupled with power next to ground planes and many on board capacitors. This puzzled me at first. But I remembered a very knowledgeable mechanical engineer once told me to never use nickel material in an application where friction takes place. Nickel has a very hard and rough surface, so in a frictional application, it always damages the mating surface. Maybe this explains the events that you saw, and the ESD generated by the metal surface was much higher than 15kv. Regards, George Tang Douglas
