F.3.2 says, "...test of F.3.1 can be carried out.....". Because it says "can" and not "shall" does this make this test optional?
Doesn't the previous version of this standard allow you to disconnect surge suppressors during the HiPot test? The Other Brian From: [email protected] [mailto:[email protected]] On Behalf Of Mick Maytum Sent: Thursday, May 10, 2012 12:00 PM To: [email protected] Cc: Doug Powell Subject: Re: [PSES] Hipot with in-circuit voltage limiting devices IEC 61010-1 3rd Ed. Doug, I wouldn't credit the TC 66 has having MOV component knowledge, just perceptions. Since my last message I have sent messages to the Chair and Secretary of TC 66 wearing my IEC SC 37B chair hat. I was restrained for a change, merely stating they were breaking the laws of physics for MOVs rather than crazy! I suggested that if the 0.9 factor was to work it should be applied to the nominal voltage not the clamping voltage. I'll keep you informed of developments if any. Regards Mick On 10/05/2012 15:15, Doug Powell wrote: Mick, Sorry I didn't review this email before I just sent my last. Clearly you see the same problem as I. I have to wonder if the committee in reviewing this clause only used data sheets and did not validate in the lab. Or is it possibly the committee members just missed this? I would like to suggest the Vclamp we should use this the 8 mS / 10 mS rating. That's mS, not uS. -- Thanks, -doug Douglas E Powell [email protected]<mailto:[email protected]> http://www.linkedin.com/in/dougp01 On Thu, May 10, 2012 at 6:58 AM, Mick Maytum <[email protected]<mailto:[email protected]>> wrote: Doug, My previous message gave the IEC rulings - terms clamping voltage and nominal varistor voltage - for two specific points on the MOV clamping (clipping) characteristic. For completeness IEC 61010-1, ed. 3.0 (2010-06) defines the following: working voltage highest r.m.s. value of the a.c. or d.c. voltage across any particular insulation which can occur when the equipment is supplied at rated voltage NOTE 1 Transients and voltage fluctuations are not considered to be part of the working voltage. NOTE 2 Both open-circuit conditions and normal operating conditions are taken into account. I'm now giving an opinion. Your (nominal) AC supply is 230V rms. The phase "not less than twice the working voltage." means the hipot test is done with an AC value of at least 460 V rms or 650 V pk. The hipot test voltage of 0.9 times the clamping voltage of the MOV is clearly crazy, as from your figures of 710 V clamping voltage and 473 V nominal varistor voltage, testing at 0.9x710 = 630 V would cause substantial current in the MOV. One could skate round this and say that the 1 mA nominal varistor voltage is the clamping threshold voltage - a new term - and use an MOV or combination of MOVs to have a nominal voltage of 650/0.9 = 720 V. Sounds like a letter to the Chair and Secretary of TC 66 is needed to resolve this matter. Regards Mick - ---------------------------------------------------------------- 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 <[email protected]<mailto:[email protected]>> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. 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 <[email protected]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> ________________________________ LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - ---------------------------------------------------------------- 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 <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
