RE: IEC 60320 C14 module MOV's
Derek, Not sure if there are any entry modules with MOV's; check www.interpower.com. You might even talk to those folks for more info. From my past life I remember that MOV's have a measurable leakage current. This current degrades the device with life and the leakage current continues to increase. This can result in overheating and/or fire as the end of life event. Many applications use a gas discharge tube in series with the MOV to stop the leakage current and, thus, the degradation. GE used to have a MOV handbook with a lot of good stuff in it; not sure if it is still available. Finally, undersized MOV's can explode under a very large fault current. This can be hazardous under some conditions. br, Pete Peter E Perkins, PE Principal Product Safety Regulatory Consultant Tigard, ORe 97281-3427 503/452-1201fone/fax p.perk...@ieee.org - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: CTL Decisions (was: RE: MOV's to ground)
I read in !emc-pstc that Arthur Michael amich...@safetylink.com wrote (in pine.bsf.4.40.0312171050350.7927-100...@shelley.shelltown.net) about 'CTL Decisions (was: RE: MOV's to ground)' on Wed, 17 Dec 2003: In my experience, the CTL Decisions are not 'normative' but are a consensus position arrived at by the CTL (Committee of Testing Labs). To my knowledge, the test labs are not bound to implement or observe these 'decisions'; The 'decisions' are documented/provided for guidance only. But don't you think that the manufacturers should know about these 'decisions', whatever they are called? Let's not argue about the exact terminology. If you like, CTL *decides* to issue a *guide* on a certain obscure matter or how the standard applies to a new situation. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
Re: CTL Decisions (was: RE: MOV's to ground)
Brian, Please see my comments below. Richard Hughes In a message dated 17/12/2003 21:41:30 GMT Standard Time, boconn...@t-yuden.com writes: Sir Most people working in the compliance field are under severe time and fiscal constraints. Official response to these issues is seldom allowed by workers at my level. REH Since I'm coming up to about 1/4 century of working in the compliance field I am fully aware of the severe time and fiscal constraints that folks in the compliance field are under. This is nothing new. REH I have no idea what 'level' you are within your company, so I couldn't comment on that point. The typical corporate reaction will not occur until the design process has been made intractable from conformity requirements. And then, it often takes the form of a political and/or legal response, backed by the fever of nationalism. REH Sorry, but I do not understand what point you are trying to convey. Please advise what I can do the make a difference, other than making statements. Your advice is appreciated. REH That depends not only on you but on this forum as a whole. This forum seems to be good a good place to exchange information, however, on 16/12/2003 Richard Georgerian asked is there enough interest within the group to start product technical committees? I thought that this was point worthy of further debate and so I sent out a proposal on 17/12/2003 which said, in part, I believe that Richard Georgerian made some useful proposals on how to move forward on the above front. However, this community would need to grow into either a professional organisation (and thereby be a voice for technical concerns, but outside the province of standards making) or a voice for industry (a kind of multinational trade association). Judging from the lack of replies to either Richard Georgerian or myself, it would seem that there is no desire to extend this forum beyond exchanging compliance information. Therefore, in reply to your question it would seem that there is nothing that you or anyone else can do in this forum to bring about change. If you wish to make a difference then my advice would be to get your employer to join a trade association and send you along as a representative. Of course this will take time and money just as it does for everyone who attends such meetings and just as it does for those of us who are involved in writing standards. Is your company willing to pay the association fees, travel costs and deal with the fact that you will have to balance internal project work against standards work? Can your company make do with the compliance situation as it is today or will it gain a sufficient competitive advantage in being able to be at the forefront of knowledge, possibly even having the ability to effect change? These are the kinds of questions cum balancing act that all companies face when they choose whether, and how actively, to participate in such organisations. Before yet another Richard (Nute) steps in, I suggest that we close the discussion at this point because it seems to have gone pretty much as far as it is going to go. Of course, you are free to reply to me individually if you wish. Respectfully, Brian
RE: CTL Decisions (was: RE: MOV's to ground)
Sir Most people working in the compliance field are under severe time and fiscal constraints. Official response to these issues is seldom allowed by workers at my level. The typical corporate reaction will not occur until the design process has been made intractable from conformity requirements. And then, it often takes the form of a political and/or legal response, backed by the fever of nationalism. Please advise what I can do the make a difference, other than making statements. Your advice is appreciated. Respectfully, Brian -Original Message- From: richhug...@aol.com [ mailto:richhug...@aol.com] Sent: Wednesday, December 17, 2003 10:13 AM To: boconn...@t-yuden.com; emc-p...@majordomo.ieee.org Subject: Re: CTL Decisions (was: RE: MOV's to ground) Brian, John, I personally think that the question of test house interpretations has deviated from the original point, though I do agree that any 'invisible' requirement is a bad thing. However, what is more important to me is what we can do about it. In the above regard I have thus far seen no reaction to my earlier contribution. Therefore I conclude that people are satisfied with making statements in the knowledge that no action is going to result, other than perhaps to elicit a me to response from others. Controversially yours, Richard Hughes
Re: CTL Decisions (was: RE: MOV's to ground)
I read in !emc-pstc that richhug...@aol.com wrote (in 15.1ed64bf4.2d11f 6...@aol.com) about 'CTL Decisions (was: RE: MOV's to ground)' on Wed, 17 Dec 2003: Brian, John, I personally think that the question of test house interpretations has deviated from the original point, though I do agree that any 'invisible' requirement is a bad thing. However, what is more important to me is what we can do about it. In the above regard I have thus far seen no reaction to my earlier contribution. Therefore I conclude that people are satisfied with making statements in the knowledge that no action is going to result, other than perhaps to elicit a me to response from others. Controversially yours, I was under the impression that you were extremely averse to controversy. It's out of season anyway. Nadolig llawen! Anyway, I replied to Richard by e-mail, because UK national committee business is involved. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
Re: CTL Decisions (was: RE: MOV's to ground)
Hello John et al, In my experience, the CTL Decisions are not 'normative' but are a consensus position arrived at by the CTL (Committee of Testing Labs). To my knowledge, the test labs are not bound to implement or observe these 'decisions'; The 'decisions' are documented/provided for guidance only. Best regards; Happy Holidays, Art Michael -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- | Thinking of joining the Product Safety Engineering Society?? | |We REBATE PSES Dues to new subscribers to IPSN| | | |Int'l Product Safety News | | P.O.Box 1561-PSES | | Middletown CT 06457-8061 U.S.A. | | Phone: (860) 344-1651 Fax: (860) 346-9066 | | | | See Details at:http://www.safetylink.com/pses/psesoffr.txt | -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- On Wed, 17 Dec 2003, John Woodgate wrote: I read in !emc-pstc that krobin...@metlabs.com wrote (in D0A7A5548389C 14e848a6fd28629251201045...@balte.metlabs-int.com) about 'CTL Decisions (was: RE: MOV's to ground)' on Wed, 17 Dec 2003: The bulletins are available for purchase in PDF Format from the IECEE Web Store to organizations that are not designated as NCB's or CBTL's (NCB's and CBTL's can obtain them from the Restricted Site as part of their Accredidation dues.):www.cbscheme.org IEC Standardssearch for Bulletins leads you to the following link:https://domino.iec.ch/websto re/webstore.nsf/artnum/030702 The posted cost is 312 CHF (approx 250 US Dollars or 200 EURO) I think this discussion has deviated from the original point. Manufacturers are required to make products that conform to standards. OK, they can buy the standards and work to them. But in the background, the CTL and, in Europe, the OSM, make decisions, known as 'interpretations', on what certain words in those standard mean, either in general or in special circumstances, **and the manufacturers have no way of even knowing that these decisions have been made, let alone what they are**. The national standards bodies either don't know or won't say. So, the manufacturer is required to work to the standard, but lurking behind it is a hidden text that he does not even know exists. This is a situation worthy of Kafka. But it is NOT about whether CTL and OSM decisions should be available free of charge, it's whether it's in any way justifiable for them to be SECRET. One former IEC Committee certainly decided that it was not justifiable and published its own list of interpretations. It remains to be seen whether its successor committee continues that policy. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
Re: CTL Decisions (was: RE: MOV's to ground)
Brian, John, I personally think that the question of test house interpretations has deviated from the original point, though I do agree that any 'invisible' requirement is a bad thing. However, what is more important to me is what we can do about it. In the above regard I have thus far seen no reaction to my earlier contribution. Therefore I conclude that people are satisfied with making statements in the knowledge that no action is going to result, other than perhaps to elicit a me to response from others. Controversially yours, Richard Hughes
RE: CTL Decisions (was: RE: MOV's to ground)
Well said, Mr. Woodgate; and it NEEDS to be said... In these United States, this can (technically) be considered illegal, and may also be considered restraint of free trade. On the civil side (but, thank god, I am not a lawyer, so my opinion is worthless) I have heard colleagues suggest that this could be remedied by a tort based on the Freedom of Information Act. luck, Brian -Original Message- From: John Woodgate [ mailto:j...@jmwa.demon.co.uk] Sent: Wednesday, December 17, 2003 5:58 AM To: emc-p...@majordomo.ieee.org Subject: Re: CTL Decisions (was: RE: MOV's to ground) I read in !emc-pstc that krobin...@metlabs.com wrote (in D0A7A5548389C 14e848a6fd28629251201045...@balte.metlabs-int.com) about 'CTL Decisions (was: RE: MOV's to ground)' on Wed, 17 Dec 2003: The bulletins are available for purchase in PDF Format from the IECEE Web Store to organizations that are not designated as NCB's or CBTL's (NCB's and CBTL's can obtain them from the Restricted Site as part of their Accredidation dues.):www.cbscheme.org IEC Standardssearch for Bulletins leads you to the following link: https://domino.iec.ch/websto re/webstore.nsf/artnum/030702 The posted cost is 312 CHF (approx 250 US Dollars or 200 EURO) I think this discussion has deviated from the original point. Manufacturers are required to make products that conform to standards. OK, they can buy the standards and work to them. But in the background, the CTL and, in Europe, the OSM, make decisions, known as 'interpretations', on what certain words in those standard mean, either in general or in special circumstances, **and the manufacturers have no way of even knowing that these decisions have been made, let alone what they are**. The national standards bodies either don't know or won't say. So, the manufacturer is required to work to the standard, but lurking behind it is a hidden text that he does not even know exists. This is a situation worthy of Kafka. But it is NOT about whether CTL and OSM decisions should be available free of charge, it's whether it's in any way justifiable for them to be SECRET. One former IEC Committee certainly decided that it was not justifiable and published its own list of interpretations. It remains to be seen whether its successor committee continues that policy. --
Re: CTL Decisions (was: RE: MOV's to ground)
I read in !emc-pstc that krobin...@metlabs.com wrote (in D0A7A5548389C 14e848a6fd28629251201045...@balte.metlabs-int.com) about 'CTL Decisions (was: RE: MOV's to ground)' on Wed, 17 Dec 2003: The bulletins are available for purchase in PDF Format from the IECEE Web Store to organizations that are not designated as NCB's or CBTL's (NCB's and CBTL's can obtain them from the Restricted Site as part of their Accredidation dues.):www.cbscheme.org IEC Standardssearch for Bulletins leads you to the following link:https://domino.iec.ch/websto re/webstore.nsf/artnum/030702 The posted cost is 312 CHF (approx 250 US Dollars or 200 EURO) I think this discussion has deviated from the original point. Manufacturers are required to make products that conform to standards. OK, they can buy the standards and work to them. But in the background, the CTL and, in Europe, the OSM, make decisions, known as 'interpretations', on what certain words in those standard mean, either in general or in special circumstances, **and the manufacturers have no way of even knowing that these decisions have been made, let alone what they are**. The national standards bodies either don't know or won't say. So, the manufacturer is required to work to the standard, but lurking behind it is a hidden text that he does not even know exists. This is a situation worthy of Kafka. But it is NOT about whether CTL and OSM decisions should be available free of charge, it's whether it's in any way justifiable for them to be SECRET. One former IEC Committee certainly decided that it was not justifiable and published its own list of interpretations. It remains to be seen whether its successor committee continues that policy. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
RE: CTL Decisions (was: RE: MOV's to ground)
The bulletins are available for purchase in PDF Format from the IECEE Web Store to organizations that are not designated as NCB's or CBTL's (NCB's and CBTL's can obtain them from the Restricted Site as part of their Accredidation dues.): www.cbscheme.org IEC Standardssearch for Bulletins leads you to the following link: https://domino.iec.ch/webstore/webstore.nsf/artnum/030702 The posted cost is 312 CHF (approx 250 US Dollars or 200 EURO) Kevin Robinson MET Laboratories From: richhug...@aol.com To: john.al...@era.co.uk; emc-p...@majordomo.ieee.org Sent: 12/17/2003 6:00 AM Subject: Re: CTL Decisions (was: RE: MOV's to ground) John, I understand from a UK NCB that the information is now published quarterly in electronic format (on the IECEE web site?). I am not an NCB and so cannot comment on this first-hand. Has anyone who is not an NCB approached the IECEE and been refused access to this information? Regards, Richard Hughes In a message dated 17/12/2003 10:43:49 GMT Standard Time, john.al...@era.co.uk writes: The CB Bulletin certainly did not used to be a private document and you used to be able subscribe to the CB Bulletin through your national standards sales organisation/outlet (e.g. from BSI in the UK, but I could'nt see any reference to it on the current IECEE site. It used to cost several hundred pounds/dollars a year, but could be well worth it even if you don't use the CB certification scheme - but it could also be somewhat out of date in paper form (do they yet do an electronic form). Regards John Allen This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
Re: CTL Decisions (was: RE: MOV's to ground)
John, I understand from a UK NCB that the information is now published quarterly in electronic format (on the IECEE web site?). I am not an NCB and so cannot comment on this first-hand. Has anyone who is not an NCB approached the IECEE and been refused access to this information? Regards, Richard Hughes In a message dated 17/12/2003 10:43:49 GMT Standard Time, john.al...@era.co.uk writes: The CB Bulletin certainly did not used to be a private document and you used to be able subscribe to the CB Bulletin through your national standards sales organisation/outlet (e.g. from BSI in the UK, but I could'nt see any reference to it on the current IECEE site. It used to cost several hundred pounds/dollars a year, but could be well worth it even if you don't use the CB certification scheme - but it could also be somewhat out of date in paper form (do they yet do an electronic form). Regards John Allen
RE: CTL Decisions (was: RE: MOV's to ground)
Hello all, I am a member of the Australian committee responsible for managing Australia's participation in IECEE, including managing how Australia participates in the CB Scheme and the IECex scheme etc. I believe the reason the IECEE CB Bulletins are restricted is economic (as always). It is more pressure from the standards writing bodies in each country than an IECEE thing I believe. Of course the IECEE need to recoup some money for producing the CB Bulletin etc but also the various national standards writing bodies are not keen on a differences list between their standard and the IEC standard being available free of charge. If they were, not many people would end up buying the national standard now would they. So the answer is yes, it is very much a copyright issue and if any CB labs were discovered making their genuinely obtained CB Bulletins available to others then that would be considered a very serious matter by the IECEE and the continued CB accreditation of such a lab I believe would be in serious jeopardy. Best regards, Kevin Richardson Stanimore Pty Limited Compliance Solutions for Technology (Legislation/Regulations/Standards/Australian Agent Services) Ph: 02-4329-4070 (Int'l: +61-2-4329-4070) Fax: 02-4328-5639 (Int'l: +61-2-4328-5639) Mobile: 04-1224-1620 (Int'l: +61-4-1224-1620) Email:kevin.richard...@stanimore.com URL: www.stanimore.com This material (this message and the information contained in all attachments to this message) is confidential and/or privileged information and is intended only for the addressee/s named above. Any unauthorised dissemination, copying, use of or reliance upon this material by persons or entities other than the addressee/s named above is prohibited. If you receive this material in error, please notify Stanimore Pty Limited and destroy all copies (electronic and hardcopy) of this message and all attachments immediately. From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Robert Johnson Sent: Wednesday, 17 December 2003 7:03 PM To: emc-p...@majordomo.ieee.org Subject: RE: CTL Decisions (was: RE: MOV's to ground) Whether copyright violations are involved depends on the conditions of the copyright. Sometimes copyrights are used to guarantee free public access to a document, for example to guarantee attribution or assure completeness. In this case it depends on the conditions issued by IECEE. They may be providing these to labs doing certification for use with their client, allowing it to be distributed to those involved. On the other hand, they may be selling them at a price per copy. Maybe they are considered secret and can't be provided to anyone but the certifying lab. Can someone at a lab or IECEE provide information regarding the conditions of the copyright? Bob Johnson ITE Safety From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Colgan Christopher [Soundcraft UK] Sent: Tuesday, December 16, 2003 12:51 PM To: emc-p...@majordomo.ieee.org Subject: RE: CTL Decisions (was: RE: MOV's to ground) CB bulletins are available from the IEC http://www.iec.ch/ but you'll have to pay. I've had copies given to me by certain test labs but it was completely unofficial and probably broke copyright laws. This is a good time of year to meet up with your test lab engineers and bribe them with a couple of drinks :) Regards Chris Colgan From: Peter L. Tarver [mailto:peter.tar...@sanmina-sci.com] Sent: 16 December 2003 16:16 To: emc-p...@majordomo.ieee.org Subject: CTL Decisions (was: RE: MOV's to ground) From: John Woodgate Why are they not in the public domain? And as much to the point, is the listing complete? More than once I've been referred to a CTL Decision that wasn't on the CB Scheme web site that was provided to someone via their CBTL or NCB. Another item of great interest is the CB Bulletin. There may be items not for public consumption, but it's referred to often enough, even in CB Scheme test reports, that it not being public is unreasonable secrecy. I've asked three different CBTLs on more than one occasion for a copy and been turned down every time, on the basis of copyright protection. Yet, I've read it on this list that it was given for the asking. Maybe I need to disguise my request in a lovely pastry or a few pints. Regards, Peter L. Tarver, PE ptar...@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.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher
RE: CTL Decisions (was: RE: MOV's to ground)
The CB Bulletin certainly did not used to be a private document and you used to be able subscribe to the CB Bulletin through your national standards sales organisation/outlet (e.g. from BSI in the UK, but I could'nt see any reference to it on the current IECEE site. It used to cost several hundred pounds/dollars a year, but could be well worth it even if you don't use the CB certification scheme - but it could also be somewhat out of date in paper form (do they yet do an electronic form). Regards John Allen ERA Technology Ltd From: Peter L. Tarver [mailto:peter.tar...@sanmina-sci.com] Sent: 16 December 2003 16:16 To: emc-p...@majordomo.ieee.org Subject: CTL Decisions (was: RE: MOV's to ground) From: John Woodgate Why are they not in the public domain? And as much to the point, is the listing complete? More than once I've been referred to a CTL Decision that wasn't on the CB Scheme web site that was provided to someone via their CBTL or NCB. Another item of great interest is the CB Bulletin. There may be items not for public consumption, but it's referred to often enough, even in CB Scheme test reports, that it not being public is unreasonable secrecy. I've asked three different CBTLs on more than one occasion for a copy and been turned down every time, on the basis of copyright protection. Yet, I've read it on this list that it was given for the asking. Maybe I need to disguise my request in a lovely pastry or a few pints. Regards, Peter L. Tarver, PE ptar...@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.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc _ This e-mail has been scanned for viruses by MCI's Internet Managed Scanning Services - powered by MessageLabs. For further information visit http://www.mci.com ** Copyright ERA Technology Ltd. 2003. (www.era.co.uk). All rights reserved. The information supplied in this Commercial Communication should be treated in confidence. No liability whatsoever is accepted for any loss or damage suffered as a result of accessing this message or any attachments. ** _ This e-mail has been scanned for viruses by MCI's Internet Managed Scanning Services - powered by MessageLabs. For further information visit http://www.mci.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
RE: CTL Decisions (was: RE: MOV's to ground)
This is a multi-part message in MIME format. Whether copyright violations are involved depends on the conditions of the copyright. Sometimes copyrights are used to guarantee free public access to a document, for example to guarantee attribution or assure completeness. In this case it depends on the conditions issued by IECEE. They may be providing these to labs doing certification for use with their client, allowing it to be distributed to those involved. On the other hand, they may be selling them at a price per copy. Maybe they are considered secret and can't be provided to anyone but the certifying lab. Can someone at a lab or IECEE provide information regarding the conditions of the copyright? Bob Johnson ITE Safety From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Colgan Christopher [Soundcraft UK] Sent: Tuesday, December 16, 2003 12:51 PM To: emc-p...@majordomo.ieee.org Subject: RE: CTL Decisions (was: RE: MOV's to ground) CB bulletins are available from the IEC http://www.iec.ch/ but you'll have to pay. I've had copies given to me by certain test labs but it was completely unofficial and probably broke copyright laws. This is a good time of year to meet up with your test lab engineers and bribe them with a couple of drinks :) Regards Chris Colgan From: Peter L. Tarver [mailto:peter.tar...@sanmina-sci.com] Sent: 16 December 2003 16:16 To: emc-p...@majordomo.ieee.org Subject: CTL Decisions (was: RE: MOV's to ground) From: John Woodgate Why are they not in the public domain? And as much to the point, is the listing complete? More than once I've been referred to a CTL Decision that wasn't on the CB Scheme web site that was provided to someone via their CBTL or NCB. Another item of great interest is the CB Bulletin. There may be items not for public consumption, but it's referred to often enough, even in CB Scheme test reports, that it not being public is unreasonable secrecy. I've asked three different CBTLs on more than one occasion for a copy and been turned down every time, on the basis of copyright protection. Yet, I've read it on this list that it was given for the asking. Maybe I need to disguise my request in a lovely pastry or a few pints. Regards, Peter L. Tarver, PE ptar...@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.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc Title: RE: CTL Decisions (was: RE: MOV's to ground) Whether copyright violations are involved depends on the conditions of the copyright. Sometimes copyrights are used to guarantee free public access to a document, for example to guarantee attribution or assure completeness. In this case it depends on the conditions issued by IECEE. They may be providing these to labs doing certification for use with their client, allowing it to be distributed to those involved. On the other hand, they may be selling them at a price per copy. Maybe they are considered secret and can't be provided to anyone but the certifying lab. Can someone at a lab or IECEE provide information regarding the conditions of the copyright? Bob Johnson ITE Safety -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Colgan Christopher [Soundcraft UK] Sent: Tuesday, December 16, 2003 12:51 PM To: emc-p...@majordomo.ieee.org Subject: RE: CTL Decisions (was: RE: MOV's to ground) CB bulletins are available from the IEC http://www.iec.ch/ but you'll have to pay. I've had copies given to me by certain test labs but it was completely unofficial and probably broke copyright laws. This is a good time of year to meet up with your test lab engineers and bribe them
Re: CTL Decisions (was: RE: MOV's to ground)
Hmmm... THat approach would get just about every salesman and marketing person fired too... Nothing wrong with having a working meeting in a pub, gets around all the red tape... Cheers ( literally :-) ) Derek. This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
Re: CTL Decisions (was: RE: MOV's to ground)
I read in !emc-pstc that Colgan Christopher [Soundcraft UK] Christopher .col...@soundcraft.com wrote (in 31F4BED1E7C6814C99079DB01681234E1B015 D@HPROUKX3) about 'CTL Decisions (was: RE: MOV's to ground)' on Tue, 16 Dec 2003: CB bulletins are available from the IEC http://www.iec.ch/ but you'll have to pay. I've had copies given to me by certain test labs but it was completely unofficial and probably broke copyright laws. This is a good time of year to meet up with your test lab engineers and bribe them with a couple of drinks :) But that is not the way to run a respectable conformity system. It is clearly open to serious abuse. Those people accepting 'drinks' are theoretically subject to instant dismissal. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
RE: CTL Decisions (was: RE: MOV's to ground)
CB bulletins are available from the IEC http://www.iec.ch/ but you'll have to pay. I've had copies given to me by certain test labs but it was completely unofficial and probably broke copyright laws. This is a good time of year to meet up with your test lab engineers and bribe them with a couple of drinks :) Regards Chris Colgan From: Peter L. Tarver [mailto:peter.tar...@sanmina-sci.com] Sent: 16 December 2003 16:16 To: emc-p...@majordomo.ieee.org Subject: CTL Decisions (was: RE: MOV's to ground) From: John Woodgate Why are they not in the public domain? And as much to the point, is the listing complete? More than once I've been referred to a CTL Decision that wasn't on the CB Scheme web site that was provided to someone via their CBTL or NCB. Another item of great interest is the CB Bulletin. There may be items not for public consumption, but it's referred to often enough, even in CB Scheme test reports, that it not being public is unreasonable secrecy. I've asked three different CBTLs on more than one occasion for a copy and been turned down every time, on the basis of copyright protection. Yet, I've read it on this list that it was given for the asking. Maybe I need to disguise my request in a lovely pastry or a few pints. Regards, Peter L. Tarver, PE ptar...@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.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
CTL Decisions (was: RE: MOV's to ground)
From: John Woodgate Why are they not in the public domain? And as much to the point, is the listing complete? More than once I've been referred to a CTL Decision that wasn't on the CB Scheme web site that was provided to someone via their CBTL or NCB. Another item of great interest is the CB Bulletin. There may be items not for public consumption, but it's referred to often enough, even in CB Scheme test reports, that it not being public is unreasonable secrecy. I've asked three different CBTLs on more than one occasion for a copy and been turned down every time, on the basis of copyright protection. Yet, I've read it on this list that it was given for the asking. Maybe I need to disguise my request in a lovely pastry or a few pints. Regards, Peter L. Tarver, PE ptar...@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.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
Re: MOV's to ground
I read in !emc-pstc that ari.honk...@nokia.com wrote (in 7B9AF58829C5D b4e869271eca2de58ea018ae...@esebe017.ntc.nokia.com) about 'MOV's to ground' on Mon, 15 Dec 2003: Fortunately, this secrecy is not complete, see http://www.iecee.org/ctl/decisions.htm Interesting. Why are they not on, or linked from, the IEC web site? -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
RE: MOV's to ground
Fortunately, this secrecy is not complete, see http://www.iecee.org/ctl/decisions.htm Regards, Ari Honkala -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of ext John Woodgate Sent: 12 December, 2003 23:03 To: emc-p...@majordomo.ieee.org Subject: Re: MOV's to ground I read in !emc-pstc that richhug...@aol.com wrote (in 1d5.16592759.2d0b 3...@aol.com) about 'MOV's to ground' on Fri, 12 Dec 2003: Perhaps someone with access to the decisions of the Committee of Test Laboratories (CTL) may be able to help find a document you can refer to. Why are they not in the public domain? Manufacturers are required to conform to standards that are 'interpreted' by these bodies but the interpretations are kept secret. That can't be right, surely? The IEC is trying to do something about it, by publishing interpretations, but the secrecy persists. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
RE: MOV's to ground
This issue was beaten to death recently; and one solution is to put the line to ground MOV in series with a gas discharge tube. A properly approved and rated gas discharge tube will practically eliminate the leakage current to ground; and provide a safeguard against the MOV failing short. Chris Maxwell Design Engineer Nettest (Currently figuring out how to get my autosignature back on my upgraded version of outlook :-) From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Tyra, John Sent: Friday, December 12, 2003 9:55 AM To: 'brian_ku...@leco.com'; jim.eich...@xantrex.com; emc-p...@majordomo.ieee.org Cc: Eszlari, Edward; Espinal, Mario; Tsitsopoulos, George Subject: RE: MOV's to ground Hello Jim You can find CTL and OSM decisions which will have information about the use of MOV's at the following link http://www.iecee.org/ctl/OSM_decisions.htm The OSM decisions are the result of meetings held by participating European Agencies where clarification is offered for standards interpretations. These are not legally binding but I have found them a big help in understanding how the Agencies interpret the standardsYou can also find CTL decisions which are very helpful. I did not see 50178 listed but I know EN60950 and EN60065 have concerns with MOV's line to earth so you may want to use this as guidance. Hope everyone finds this useful. Regards, John From: brian_ku...@leco.com [mailto:brian_ku...@leco.com] Sent: Friday, December 12, 2003 8:29 AM To: jim.eich...@xantrex.com; emc-p...@majordomo.ieee.org Subject: Re:MOV's to ground Jim, You want to look at the EN60950 CCA document (not sure where to get the latest copy). Attached is a WORD file that has a section of an older CCA document that addresses this issue. I got it from a TUV office. Brian Reply Separator Subject:MOV's to ground Author: jim.eich...@xantrex.com List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: 12/11/03 6:27 PM Sorry - I know this has been flogged to death, but can someone please point me to something in writing that says you can't have MOV's to ground in a product destined for Germany? Or has that gone away? Any other countries with the same or similar rules? We are not in EN60950 - this is an EN50178 question, but really it's a general question. Thanks, Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. e-mail: jim.eich...@xantrex.com web: www.xantrex.com Any opinions expressed are purely accidental. Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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
Re: MOV's to ground
I read in !emc-pstc that richhug...@aol.com wrote (in 1d5.16592759.2d0b 3...@aol.com) about 'MOV's to ground' on Fri, 12 Dec 2003: Perhaps someone with access to the decisions of the Committee of Test Laboratories (CTL) may be able to help find a document you can refer to. Why are they not in the public domain? Manufacturers are required to conform to standards that are 'interpreted' by these bodies but the interpretations are kept secret. That can't be right, surely? The IEC is trying to do something about it, by publishing interpretations, but the secrecy persists. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
RE: MOV's to ground
Thanks to everyone who replied. I was not aware that the answer was dependent on the power system (TN-s vs. others) having been under the impression that the issue was about increasing leakage current throughout the life of the product. As always the forum is vastly useful! Thanks, Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. e-mail: jim.eich...@xantrex.com web: www.xantrex.com Any opinions expressed are purely accidental. Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. From: Jim Eichner [mailto:jim.eich...@xantrex.com] Sent: Thursday, December 11, 2003 3:10 PM To: 'EMC-PSTC - forum' Subject: MOV's to ground Sorry - I know this has been flogged to death, but can someone please point me to something in writing that says you can't have MOV's to ground in a product destined for Germany? Or has that gone away? Any other countries with the same or similar rules? We are not in EN60950 - this is an EN50178 question, but really it's a general question. Thanks, Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. e-mail: jim.eich...@xantrex.com web: www.xantrex.com Any opinions expressed are purely accidental. Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
Re: MOV's to ground
Jim, Perhaps someone with access to the decisions of the Committee of Test Laboratories (CTL) may be able to help find a document you can refer to. Ken has explained one of the problems associated with MOVs, whether from line to line or line to earth. My understanding is that the failure mechanism is not to go straight from an open circuit to a dead-short, but rather a continued reduction in resistance with each hit. Hence, when used from line to ground, your equipment would probably fail to meet the protective conductor (leakage) current before you see thermal problems with the MOVs. You may also be unlucky in finding a generic answer applicable to all standards. I have been involved in discussing this topic as regards IEC/EN 60950-1, but not with EN 50178. My recollection is that for Pluggable Type A equipment (e.g. regular domestic plugs) Germany permit the use of MOVs in series with gas tubes from line to ground. Other countries accept this with the proviso that the gas tube meets the requirements for Basic Insulation. There is an IEC standard (IEC 61051-2) covering MOVs and it is of course recommended that you use such components. Of course, it is also possible to purchase MOVs with a built-in thermal fuse - great for ensuring that your equipment doesn't catch on fire, but perhaps of limited use for continued protection against transient voltages! Not exactly what you were looking for, but hopefully a few pointers for you to follow-up with... Regards, Richard Hughes Safety Answers Limited www.safetyanswers.ltd.uk
RE: MOV's to ground
Hello Jim You can find CTL and OSM decisions which will have information about the use of MOV's at the following link http://www.iecee.org/ctl/OSM_decisions.htm The OSM decisions are the result of meetings held by participating European Agencies where clarification is offered for standards interpretations. These are not legally binding but I have found them a big help in understanding how the Agencies interpret the standardsYou can also find CTL decisions which are very helpful. I did not see 50178 listed but I know EN60950 and EN60065 have concerns with MOV's line to earth so you may want to use this as guidance. Hope everyone finds this useful. Regards, John From: brian_ku...@leco.com [mailto:brian_ku...@leco.com] Sent: Friday, December 12, 2003 8:29 AM To: jim.eich...@xantrex.com; emc-p...@majordomo.ieee.org Subject: Re:MOV's to ground Jim, You want to look at the EN60950 CCA document (not sure where to get the latest copy). Attached is a WORD file that has a section of an older CCA document that addresses this issue. I got it from a TUV office. Brian Reply Separator Subject:MOV's to ground Author: jim.eich...@xantrex.com List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: 12/11/03 6:27 PM Sorry - I know this has been flogged to death, but can someone please point me to something in writing that says you can't have MOV's to ground in a product destined for Germany? Or has that gone away? Any other countries with the same or similar rules? We are not in EN60950 - this is an EN50178 question, but really it's a general question. Thanks, Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. e-mail: jim.eich...@xantrex.com web: www.xantrex.com Any opinions expressed are purely accidental. Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
RE: MOV's to ground
Jim, Ken, is correct in that when MOV's fail, they fail short. That is why you see a circuit breaker or fuse in front of the MOV's. If your safety ground is defective or does not return to the neutral side of the power source, then your safety ground raises to line potential when the MOV's short line to safety ground, with significant current available. In a case like this the failure does not trip the circuit breakers or fuses in the electrical panel. We had a such a failure here (multiple failures were to blame) and the only thing damaged were 26 MOVs (in 26 electrical strips) that were line to safety ground. None of the computers plugged into the strips were damaged, even though fuses blew to protect the MOVs (after letting the smoke out of the MOVs), but left the computers powered up. None of the computers had MOVs line to safety ground. In our case the cubical area is three phase (115VAC 60Hz). One cubical was miss wired, which put the neutral to safety ground MOV in the none fused part of the electrical strip, in to the line side of the circuit. The main electrical box for the area was not properly grounded, nor was the safety ground tied to the neutrals. So when the MOV failed it raised the safety ground to the line potential of phase A, which put 230VAC across all the MOV's on Phase B and Phase C. As Murphy would have it the MOV that failed had a unintentional heatsink and survived longer than it should have. All the other MOV's did not have heatsinks. The reality is you should never really need a MOV from line to safety ground (or neutral to safety ground). It is the difference in potential that destroys semiconductors. In most designs the semiconductors are line to neutral not line to ground. So as long as you have one across line to neutral you should be OK (not to mention the filters that assist). The past discussions on this subject can be found in our archive on : https://www.ieeecommunities.org/emc-pstc?go=t907166 Jim Jim Bacher, Senior Engineer Paxar Americas, Inc. e-mail: j.bac...@ieee.org From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Ken Javor Sent: Thursday, December 11, 2003 11:08 PM To: Jim Eichner; 'EMC-PSTC - forum' Subject: Re: MOV's to ground Not a legal answer, but I have seen a failure mode for MOVs where they partially conduct line current. This was in power strips. My house electrical system took a lightning hit. Nothing was damaged but the MOVs, including all the stuff in the house not connected to MOV protected power strips. The power strips with bad MOVs were quite hot (thermally) due to the fault current (high impedance short to ground). The MOVs were tiny, I think larger ones might have fared better. No doubt there is a spec covering how many Joules/Watts an MOV must be able to absorb without damage. This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
Re: MOV's to ground
Not a legal answer, but I have seen a failure mode for MOVs where they partially conduct line current. This was in power strips. My house electrical system took a lightning hit. Nothing was damaged but the MOVs, including all the stuff in the house not connected to MOV protected power strips. The power strips with bad MOVs were quite hot (thermally) due to the fault current (high impedance short to ground). The MOVs were tiny, I think larger ones might have fared better. No doubt there is a spec covering how many Joules/Watts an MOV must be able to absorb without damage. From: Jim Eichner jim.eich...@xantrex.com Reply-To: Jim Eichner jim.eich...@xantrex.com Date: Thu, 11 Dec 2003 15:10:21 -0800 To: 'EMC-PSTC - forum' emc-p...@majordomo.ieee.org Subject: MOV's to ground Sorry - I know this has been flogged to death, but can someone please point me to something in writing that says you can't have MOV's to ground in a product destined for Germany? Or has that gone away? Any other countries with the same or similar rules? We are not in EN60950 - this is an EN50178 question, but really it's a general question. Thanks, Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. e-mail: jim.eich...@xantrex.com web: www.xantrex.com Any opinions expressed are purely accidental. Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
MOV's to ground
Sorry - I know this has been flogged to death, but can someone please point me to something in writing that says you can't have MOV's to ground in a product destined for Germany? Or has that gone away? Any other countries with the same or similar rules? We are not in EN60950 - this is an EN50178 question, but really it's a general question. Thanks, Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. e-mail: jim.eich...@xantrex.com web: www.xantrex.com Any opinions expressed are purely accidental. Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com 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.ieeecommunities.org/emc-pstc
RE: MOV's (Varistor to Earth)
Spencer, It is possible to get UL 1449 approved MOVs up to 16 Amps, I think. See http://ulstandardsinfonet.ul.com/scopes/1449.html I find that because of the added capacitance of the MOV, the leakage current can go up unacceptably. I will typically couple the MOV with a gas tube that is rated higher than the line voltage. You now have to think about the voltages of the two keeping in mind the trip points and the fact that the gas tube clamps to ground while the MOV clamps to a voltage. -doug end Douglas E. Powell Corporate Compliance Dept. Advanced Energy Industries, Inc. Fort Collins, CO 80535 USA From: Spencer, David H [mailto:david.spen...@usa.xerox.com] Sent: Wednesday, September 10, 2003 9:49 AM To: 'emc-p...@ieee.org' Subject: MOV's (Varistors to Earth) Howdy All, I was curious if anyone out there has place a separately certified MOV from Line (or Neutral) to Earth as a solution for Surge and placement in the EU. The specific application is a pluggable Type B. The OSM/EE Note 1.5.1 98/2 indicates that for Pluggable Type B (and permanently connected) equipment that provided the MOV is separately certified it is an acceptable option. See: http://www.lyons.demon.co.uk/cenlec01.pdf For my part this is a check to insure there are no other superceding requirements that would not allow a MOV from Line to Earth in the EU. Also, are most MOV's separately certified? Any additional information would be appreciated. Best Regards David Spencer 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ___ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
MOV's (Varistors to Earth)
Howdy All, I was curious if anyone out there has place a separately certified MOV from Line (or Neutral) to Earth as a solution for Surge and placement in the EU. The specific application is a pluggable Type B. The OSM/EE Note 1.5.1 98/2 indicates that for Pluggable Type B (and permanently connected) equipment that provided the MOV is separately certified it is an acceptable option. See: http://www.lyons.demon.co.uk/cenlec01.pdf For my part this is a check to insure there are no other superceding requirements that would not allow a MOV from Line to Earth in the EU. Also, are most MOV's separately certified? Any additional information would be appreciated. Best Regards David Spencer 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Line-ground MOV's
Joachim: I believe you're right on! MOVs degrade with repeated hits. Perhaps the answer is the silicon TVS products from ON Semi and others. Chuck jl...@astex.mksinst.com wrote: Greetings, To meet immunity requirements I will get a line filter which will include three line-ground MOV's, (275V). To my opinion this may be a safety issue due to the danger to increase the leakage current especially after an overload of the MOV's. Am I in the right or is this not an issue regarding the Low Voltage Directive? Joachim Lohr ASTeX GmbH Tel.: ++49 30 464 003 19 jl...@astex.mksinst.com --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Line-ground MOV's
Greetings, To meet immunity requirements I will get a line filter which will include three line-ground MOV's, (275V). To my opinion this may be a safety issue due to the danger to increase the leakage current especially after an overload of the MOV's. Am I in the right or is this not an issue regarding the Low Voltage Directive? Joachim Lohr ASTeX GmbH Tel.: ++49 30 464 003 19 jl...@astex.mksinst.com --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
[Fwd: Re:Oh those maddening MOV's!!]
Forwarded for Jim Bacher Original Message Subject: Re:Oh those maddening MOV's!! List-Post: emc-pstc@listserv.ieee.org Date: Mon, 2 Apr 2001 16:34:21 -0500 From: jim_bac...@mail.monarch.com (Jim Bacher) To: McCoy; Paul pmc...@systemationusa.com,'emc-p...@majordomo.ieee.org' emc-p...@majordomo.ieee.org Popcorn and Smoke, this is not an answer to your question, just an interesting failure of MOV's that relates to your question. About five years ago, first thing in the morning, as everybody came into the wing I was in, they would turn on the electrical strips that their PC's were plugged into. And most of the strips contained MOV's. A few minutes later there would be a POP and smoke would pour out (flames in a few cases) of the electrical strip. In the matter of a few minutes we lost over 25 electrical strips. It was the same morning and the same time they were scrolling messages on who had just bought our company. It seems that one of our cubes had been miss wired. It seems that line and neutral had been reversed. As a result the fuse / circuit breaker of the electrical strip was in the neutral leg rather than the line side. As MOV's do once in a while, the MOV that was line to ground failed as a short circuit (the MOV without the protection). The MOV happened to be wedged against the metal of the strip so it could dissipate a little more power than normal. Once it shorted to ground some even more interesting things happened. Our wing is run on three phases. It turns out that the ground was not installed correctly and a main ground wire to the wing had failed. So when the MOV shorted, it basically lifted the ground of our wing to phase A's potential. All of the MOV's on phase B and C then had twice their nominal voltage applied and without having the extra heat sinking that the first MOV had, they were popping like popcorn. None of the computers were damaged, only the electrical strips were damaged. Jim Jim Bacher, Senior Engineer Paxar - Monarch e-mail: jim_bac...@monarch.com voice: 1-937-865-2020 fax: 1-937-865-2048 Reply Separator Subject:Oh those maddening MOV's!! Author: McCoy; Paul pmc...@systemationusa.com List-Post: emc-pstc@listserv.ieee.org Date: 4/2/01 3:30 PM Group, I know in conversations and threads past there has been discussion on the use of MOV's and gas arrestors for the main power input. Specifically at which times and under what conditions an MOV can be placed between LINE and PE. Could some one please tell me what standard (standards?) these requirements come from? Thank you, Paul McCoy --- 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,
Oh those maddening MOV's!!
Group, I know in conversations and threads past there has been discussion on the use of MOV's and gas arrestors for the main power input. Specifically at which times and under what conditions an MOV can be placed between LINE and PE. Could some one please tell me what standard (standards?) these requirements come from? Thank you, Paul McCoy --- 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: MOV's
On Thu, 12 Oct 2000 13:22:30 EDT, lfresea...@aol.com wrote: does anyone have a SPICE model for an MOV? Thanks, Derek. Take a look at the models offered by Intusoft http://www.intusoft.com/Models.htm , and look for the 'Varistors' link. Also try Littelfuse. They now own the Harris/GE varistor product line: http://www.littelfuse.com/ Do a search for the LA product series. There's a link at the bottom of the page for the SPICE models. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
MOV's
Hi, does anyone have a SPICE model for an MOV? Thanks, Derek. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Requirements For MOV's
I know this is a rehash of a topic from six months ago.. Sorry. I would like to find a break down of the requirements for MOV's ( this is only in AC mains applications) 1) By country (EU countries primarily.. But Globally is good info too.) 2) What safety markings ( on the device) are required? 3) What application limitations there are ; i.e. is Line-to-Line, vs. Line-to-Ground? 4) Are there national deviations regarding the application specifics? 5) What are the installation requirements? Any comments or direction on this would be appreciated. Regards David Spencer Xerox Corporation attachment: Spencer,_David_H.vcf
RE: MOV's Vs Unipolar Suppressors
Darrell: Is Transorb a brand name? On a prototype level I recently tried AVX Transguard with success against positive and negative ESD Pulses up to 8KV air discharge. These parts according to the mfg. are MLVs, Multilayer Varistors and act in a bipolar manner. Best Regards, Bill Jacowleff VDO Control Systems Airpax Instruments 150 Knotter Drive Cheshire, CT 06410 Phone: 203 271-6394 FAX:203 271-6200 bjacowl...@vdo.com -Original Message- From: Darrell Locke (MSMail) [mailto:dlo...@advanced-input.com] Sent: Wednesday, August 04, 1999 12:48 PM To: 'emc-p...@majordomo.ieee.org' Subject: MOV's vs Unipolar Suppressors Compliance Collegues, I have a question on MOV's (bi-polar) vs Transorbs (unipolar) devices for board level transient protection, specifically ESD pulses that are very fast rising. The MOV type devices are inexpensive and come in arrays, so theyr'e pretty easy to use. I have heard arguments against these type of devices because a negative going pulse can drive an IC pin below ground (greater than a diode drop) and cause the IC to be damaged by sourcing a large current. Some engineers prefer a unipolar device for this purpose. I have not however, seen this to occur in the test lab. Has anyone experimented or have opinions on this? Thanks Darrell Locke - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
MOV's vs Unipolar Suppressors
Compliance Collegues, I have a question on MOV's (bi-polar) vs Transorbs (unipolar) devices for board level transient protection, specifically ESD pulses that are very fast rising. The MOV type devices are inexpensive and come in arrays, so theyr'e pretty easy to use. I have heard arguments against these type of devices because a negative going pulse can drive an IC pin below ground (greater than a diode drop) and cause the IC to be damaged by sourcing a large current. Some engineers prefer a unipolar device for this purpose. I have not however, seen this to occur in the test lab. Has anyone experimented or have opinions on this? Thanks Darrell Locke - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Re(2): Insulation on MOV's
The other reason for putting tubing on MOV's is to direct (or contain) the resulting explosion. Tubing helps direct the discharge away from other circuits which may compromise spacings. -Original Message- From: s_doug...@ecrm.com [mailto:s_doug...@ecrm.com] Sent: Monday, January 11, 1999 2:16 PM To: jrbar...@lexmark.com Cc: emc-p...@majordomo.ieee.org Subject:Re(2): Insulation on MOV's jrbar...@lexmark.com writes: The vendor who designed and built the power supply for us put thick-wall heat-shrink tubing over the MOV to provide a safety barrier, since the dipped epoxy coating was considered to be only operational insulation. This reminds me of a product we made about 10 years ago. We put MOV's on a terminal block in the primary circuit to solve a problem. Had no trouble with that but I recall one of the agencies (UL, CSA, TUV) made us put heatshrink over the body of each MOV. Now I find out why. Regards, Scott s_doug...@ecrm.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). - 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: Use of MOV's ???
That's right, if any MOV fails, it fails by leaking more and more and more and more and then somebody is going to say aauauauauaua:((( No kidding, you may use MOV's for surge suppressing between phases, but not connect it to ground for the reasons above. You may use MOV's for surge suppressing between phases, but not connect it to ground for every MOV that fails slowly start leaking and leaking and finishes as a short circuit. In the philosophy of LVD a double protection of a Class 1 apparatus consists of: - Isolation + earth bounding ( 2 levels of protection agains electric shock) That would invalid one of the protection layers, as the MOV is no isolation , and not equivalent to an isolation layer. BTW Double Isolated apparatus Class II have two protection layers too, Isolation + extra isolation. ( 2 levels of protection agains electric shock) In both classes a single failure would not lead to catastrophy. I suppose the guys at UL started to learn something from their TUV german collegues ?! 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 -Oorspronkelijk bericht- Van: colli...@perkin-elmer.com colli...@perkin-elmer.com Aan: emc-p...@ieee.org emc-p...@ieee.org Datum: dinsdag 21 april 1998 16:46 Onderwerp: Re: Use of MOV's ??? I recently received an e-mail from a colleague on the east coast stating that UL has joined TUV Rheinland in NOT accepting the use of MOV's in primary circuitry. The reasoning behind this is due to the unpredictable dielectric break down of these components which can increase leakage current beyond acceptable levels. Has anyone heard any truth to these statements ? If so, what other methods are being used to solve problems without these devices? Your comments are appreciated, Jeff Collins EMC/Product Safety Engineer Perkin-Elmer Applied Biosystems colli...@perkin-elmer.com
RE: Use of MOV's ???
Jeff - This rumor doesn't make much sense as an across-the-board requirement, especially considering UL has a component product category for MOVs and other transient voltage surge suppressors, along with some product standards that allow reductions of over-surface and through-air electrical spacings when transients are known and/or controlled. Presumably, your friend means one specific product category or standard, but even then it makes little sense for US application. Could it be that this rumor is based on certain EU countries not wanting MOVs in primary circuits, based on the nature of their power systems and UL is enforcing this requirement for CB Scheme evaluations where specific national deviations come into play? I've seen no official mailing from UL on this topic. Such a drastic measure, after accepting MOVs in primary circuits for a long time, would require a formal Industry Review (File Review), with announced schedules for product compliance. If your friend has more information on this, please convince them to pass it along. Regards, Peter L. Tarver Homologation Engineering Dept. 4D02-4 MPK MS: D-2120 V: ESN 655-2453 F: ESN 655-2575 -- From: colli...@perkin-elmer.com[SMTP:colli...@perkin-elmer.com] Sent: Monday, April 20, 1998 11:31 AM I recently received an e-mail from a colleague on the east coast stating that UL has joined TUV Rheinland in NOT accepting the use of MOV's in primary circuitry. The reasoning behind this is due to the unpredictable dielectric break down of these components which can increase leakage current beyond acceptable levels. Has anyone heard any truth to these statements ? If so, what other methods are being used to solve problems without these devices? Your comments are appreciated, Jeff Collins EMC/Product Safety Engineer Perkin-Elmer Applied Biosystems colli...@perkin-elmer.com
Re: Use of MOV's ???
I recently received an e-mail from a colleague on the east coast stating that UL has joined TUV Rheinland in NOT accepting the use of MOV's in primary circuitry. The reasoning behind this is due to the unpredictable dielectric break down of these components which can increase leakage current beyond acceptable levels. Has anyone heard any truth to these statements ? If so, what other methods are being used to solve problems without these devices? Your comments are appreciated, Jeff Collins EMC/Product Safety Engineer Perkin-Elmer Applied Biosystems colli...@perkin-elmer.com
RE: MOV's
One possibility is a MOV in series with a fuse (or spark gap in some cases.) The MOV limits overvoltage current, the fuse or spark gap provides required voltage standoff. ___ Heber Farnsworth, P.E. Physio-Control Corp, Seattle, USA -Original Message- From: Stewart, Judd [SMTP:stewart.jud...@sd.littondsd.com] Sent: Thursday, February 19, 1998 2:00 PM To: 'EMC-PST' Subject: MOV's Hello from San Diego, Does anyone know of components that will meet the requirements of EN60950 and also function as a MOV. The component will bridge basic insulation in a primary circuit. Thanks Judd Stewart Litton Data Systems 619.623.6639
RE: MOV's
Hello Jim, I do not think it is wise to use any component between phase and ground having a CM voltage limiting function. No component fits the requirements of EN 60950 RELIABLE for sufficient amount of time. I want re refer here to the requirements for solid state switches in EN 60730 which are severe, and just for differential mode. Especially MOV resistors tend to short circuit after a number of limiting actions, after a period of increasing leakage current. Regards, Ing. Gert Gremmen == CE-test, qualified testing, Consultancy, Compliance tests for EMC and Electrical Safety 15 Great EMC-design tips available ! Visit our site : http://www.cetest.nl The Dutch Electronics Directory http://www.cetest.nl/electronics.htm == -Oorspronkelijk bericht- Van:Stewart, Judd [SMTP:stewart.jud...@sd.littondsd.com] Verzonden: donderdag 19 februari 1998 23:00 Aan:'EMC-PST' Onderwerp: MOV's Hello from San Diego, Does anyone know of components that will meet the requirements of EN60950 and also function as a MOV. The component will bridge basic insulation in a primary circuit. Thanks Judd Stewart Litton Data Systems 619.623.6639
MOV's
Hello from San Diego, Does anyone know of components that will meet the requirements of EN60950 and also function as a MOV. The component will bridge basic insulation in a primary circuit. Thanks Judd Stewart Litton Data Systems 619.623.6639
Spark-gaps, MOV's and other breakover devices---
In my opinion, any device that shifts from a high impedance to a low impedance to protect an attached, parallel load, needs another part. The additional part is a series energy limiter, examples a PTC device, an inductor, a resistor, a fuse, etc. The resulting circuit is nothing more than a shunt regulator with the load and breakover device at the same voltage, the remainder across the series limiter and the mains impedance. The mains impedance tends towards 1/2% per unita very small number. This point was made several years ago when an ambitious marketer brought a voltage suppressor comprised of several MOV's in parallel across the mains, and nothing else. We gave it single simulated lightning disturbance---when the smoke cleared all that remained of the suppressor was a dark stain on the test bench. bo...@vnet.ibm.com
