Hi Bostjan, This is an interesting question. A few thoughts:
- Have you measured the touch current? Per 5.2.2.5 for repetitive pulses, if the voltage exceeds the limit of Table 8, then the current shall not exceed the limit. So if your peak touch current is less than 0.707 mA, ES1 classification is OK independently of which voltage limit you apply. - This is supported by the description of ES2 in 5.2.1.2, which requires an ES2 circuit to exceed *both* the ES1 prospective touch voltage limit and the ES1 touch current limit. - 0.707mA appears to be the most stringent touch current limit from Table 4, so if you don't exceed this value it doesn't really matter if you classify it as a repetitive peak voltage or combined ac/dc. - If you don't like the touch current route, you could probably make an argument for treating the longer pulse as combined ac/dc. It does have a frequency and does not meet the definition of d.c. voltage in 3.3.14.1, but single pulses with off time >3s use the dc limits for ES1 based on Tables 6 and 7. So you could consider the single pulse portion as not actually dc, but that the dc limits are appropriate to apply. The touch current route is cleaner as it is clearly supported in the standard. On Fri, Mar 8, 2019 at 8:05 AM John Woodgate <j...@woodjohn.uk> wrote: > Trouble is, you can never be sure . It might be Air Force 1 that gets > the EMI! > > On 2019-03-08 15:56, Ken Javor wrote: > > Re: [PSES] classification of the output Unless the output overload > > test modeled something that occurred fairly often in practice, it > > seems to me that EMI caused during such an event would not be a > > serious issue. > > > > Ken Javor > > Phone: (256) 650-5261 > > > > > > ------------------------------------------------------------------------ > > *From: *John Woodgate <j...@woodjohn.uk> > > *Reply-To: *John Woodgate <j...@woodjohn.uk> > > *Date: *Fri, 8 Mar 2019 09:41:41 +0000 > > *To: *<EMC-PSTC@LISTSERV.IEEE.ORG> > > *Subject: *Re: [PSES] classification of the output > > > > > > > > There are serious EMC implications as well. Since most EMC testing > > doesn't cover overload conditions, the effect you describe could > > result in many complaints of EMI in the field. > > > > > > Best wishes > > John Woodgate OOO-Own Opinions Only > > J M Woodgate and Associates www.woodjohn.uk <http://www.woodjohn.uk> > > <http://www.woodjohn.uk> > > Rayleigh, Essex UK > > > > On 2019-03-08 09:24, Boštjan Glavič wrote: > > > > > > > > > > > > Dear all, > > > > > > > > I would need your advice about classification of the output of > > power supply during abnormal operation. I know that quite many > > discussions were already done, but this was with regard of touch > > current. > > > > > > > > During output overload test unit goes in hiccup mode. There are > > more than 3s between main pulses. Pulse voltage does not exceed > > 60V (see picture 1). The problem is that each pulse (hiccup) is > > composed of small pulses (see second picture). How to treat this > > output? > > > > > > > > Customer is not happy with ES2 classification. > > > > > > > > Can we each pulse separate to AC and DC part and try with limit > > for Combined AC and DC? > > > > > > > > Thank you for your support. > > > > > > > > Best regards, > > > > Bostjan > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Picture 1 – output hiccup. > > > > > > > > > > > > Picture 2 – zoom of individual pulse > > > > > > > > > > > > - > > ---------------------------------------------------------------- > > > > 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.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://www.ieee-pses.org/list.html (including how > > to unsubscribe) <http://www.ieee-pses.org/list.html> > > <http://www.ieee-pses.org/list.html> > > List rules: http://www.ieee-pses.org/listrules.html > > > > > > For help, send mail to the list administrators: > > Scott Douglas <sdoug...@ieee.org> > > Mike Cantwell <mcantw...@ieee.org> > > > > > > For policy questions, send mail to: > > Jim Bacher <j.bac...@ieee.org> > > David Heald <dhe...@gmail.com> > > > > - > > ---------------------------------------------------------------- > > > > This message is from the IEEE Product Safety Engineering Society > > emc-pstc discussion list. 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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://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://www.ieee-pses.org/list.html (including how to > > unsubscribe) > > List rules: http://www.ieee-pses.org/listrules.html > > > > For help, send mail to the list administrators: > > Scott Douglas <sdoug...@ieee.org <mailto:sdoug...@ieee.org>> > > 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 email has been checked for viruses by AVG. > https://www.avg.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://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://www.ieee-pses.org/list.html (including how to > unsubscribe) > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <sdoug...@ieee.org> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher: <j.bac...@ieee.org> > David Heald: <dhe...@gmail.com> > -- Scott Aldous | Regulatory Compliance Program Manager | scottald...@google.com | 650-253-1994 - ---------------------------------------------------------------- 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.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://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
