Re: [PSES] MOV requirements
Does the industry really need another standard, I wonder? _ Ralph McDiarmid | Schneider Electric | Renewable Energies Business | CANADA | Regulatory Compliance Engineering From: John Woodgate j...@jmwa.demon.co.uk To: EMC-PSTC@LISTSERV.IEEE.ORG Date: 11/11/2011 06:48 AM Subject: Re: [PSES] MOV requirements In message 4ebd2d05.5050...@ieee.org, dated Fri, 11 Nov 2011, Mick Maytum m.j.may...@ieee.org writes: MOV, Varistor, VDR; Metal-Oxide Varistor are all names for a voltage-limiting component using a particular technology. I think this 'particular technology' is an important point. As I understand it, devices like Transorbs (TM?) are quite different from MOVs, being avalanche diodes with a very high thermal capacity. They seem to be rarely used (cost?) but have desirable characteristics (like not exploding!). Are there relevant standards? -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK Some people who are peeling the finch of the financial crisis are thinking of biting a rook. - 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://product-compliance.oc.ieee.org/ 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...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com __ This email has been scanned by the MessageLabs Email Security System. __ - 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://product-compliance.oc.ieee.org/ 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...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] MOV requirements
To further abuse a meme - moar standards! [insert troll-face here] Another member has previously commented that there a several type of components used to arrest a surge. For the purpose of my OP, was focused on a MOV-type SPD as defined under UL CCNs VZCA2 and VZCA8, where the effective standards are UL1449 and CSA C233.1, and various CSA TILs. And of course, the wondrous IEC61051-2. This is another case where EMC requirements (61000-4-5,6) can affect product safety. Last year's update to the 2d ed of 60950-1 for my component power supplies was, for some models, quite an adventure. A problem NOT ADDRESSED by TC108 is the increased energy AFTER a surge, or during a SFC, due to the 120% rating requirement. Perhaps this was a principal intent of UL1449 3d ed - verify that the high E and I do not make the MOV puke it guts and start a fire. There are many sources of increased energy - my two problem children are the effects of an inductive kick to the circuit being 'protected' by the SPD *after* the current interrupt device has opened; and the higher voltage (CV^2), during a surge, at which the SPD will start conducting. As for GDTs - they take longer to get to low Z. And zener-type arrestors do not have a sharp knee at the conduction level. The ZnO MOV seems to be the best chance of survival, assuming the other circuit components can handle much higher coulombs running around before clamping. Moar standards! Moar unintended effects! Moarrr Brian -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of ralph.mcdiar...@schneider-electric.com Sent: Monday, November 14, 2011 11:31 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] MOV requirements Does the industry really need another standard, I wonder? Ralph McDiarmid | Schneider Electric | Renewable Energies Business | CANADA | Regulatory Compliance Engineering From: John Woodgate j...@jmwa.demon.co.uk To: EMC-PSTC@LISTSERV.IEEE.ORG Date: 11/11/2011 06:48 AM Subject: Re: [PSES] MOV requirements In message 4ebd2d05.5050...@ieee.org, dated Fri, 11 Nov 2011, Mick Maytum m.j.may...@ieee.org writes: MOV, Varistor, VDR; Metal-Oxide Varistor are all names for a voltage-limiting component using a particular technology. I think this 'particular technology' is an important point. As I understand it, devices like Transorbs (TM?) are quite different from MOVs, being avalanche diodes with a very high thermal capacity. They seem to be rarely used (cost?) but have desirable characteristics (like not exploding!). Are there relevant standards? -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - 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://product-compliance.oc.ieee.org/ 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...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] MOV requirements
Ralph, The answer to your question is in the US arm of your own company. Drop a line to James Moellmann, who has recently been to the IEC meetings in China and IEEE meetings in Florida all concerned with yet more standards on MOV-protected devices and equipment. Regards Mick On 14/11/2011 19:30, ralph.mcdiar...@schneider-electric.com wrote: Does the industry really need another standard, I wonder? _ * Ralph McDiarmid* | *Schneider Electric ** | Renewable Energies Business* | *CANADA* | *Regulatory Compliance Engineering* From: John Woodgate j...@jmwa.demon.co.uk To: EMC-PSTC@LISTSERV.IEEE.ORG Date: 11/11/2011 06:48 AM Subject:Re: [PSES] MOV requirements In message 4ebd2d05.5050...@ieee.org, dated Fri, 11 Nov 2011, Mick Maytum m.j.may...@ieee.org writes: MOV, Varistor, VDR; Metal-Oxide Varistor are all names for a voltage-limiting component using a particular technology. I think this 'particular technology' is an important point. As I understand it, devices like Transorbs (TM?) are quite different from MOVs, being avalanche diodes with a very high thermal capacity. They seem to be rarely used (cost?) but have desirable characteristics (like not exploding!). Are there relevant standards? -- OOO - Own Opinions Only. Try www.jmwa.demon.co.ukand www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK Some people who are peeling the finch of the financial crisis are thinking of biting a rook. - 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://product-compliance.oc.ieee.org/ 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...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com __ This email has been scanned by the MessageLabs Email Security System. __ - 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 mailto:emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at http://product-compliance.oc.ieee.org/ 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...@radiusnorth.net mailto:emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org mailto:mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org mailto:j.bac...@ieee.org David Heald dhe...@gmail.com mailto:dhe...@gmail.com - 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://product-compliance.oc.ieee.org/ 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...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
