Yes, but in this case, disconnection is not an option.
Thanks, -doug Douglas E Powell [email protected] http://www.linkedin.com/in/dougp01 On Thu, May 10, 2012 at 1:52 PM, Kunde, Brian <[email protected]>wrote: > 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] > > http://www.linkedin.com/in/dougp01 > > > > > > > > On Thu, May 10, 2012 at 6:58 AM, Mick Maytum <[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]> > > 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]> > ------------------------------ > *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]> > - ---------------------------------------------------------------- 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]>
