Hi Brian, When our customers have asked us to address this problem, we use a combination of 320VAC MOVs and a 470V gas tube suppressor. The MOVs are connected in series from phase-phase, and the gas tube is connected from the MOV centertap to ground. To prevent false hipot failures, the gas tube is installed after the power supply is hipotted.
Maybe someone else can address whether this is acceptable in all countries. Pat Lawler EMC Engineer SL Power Electronics Corp. "Kunde, Brian" <[email protected]> wrote on 09/01/2010 11:57:07 AM: > Most all over the counter power supplies will pass the 2KV Line – PE > surge immunity test (IEC 61000-4-5) when tested stand-a-lone, > however, when these power supplies are used in an assembly with > other Mains driven devices through a large Line Filter, the surge > pulse seen at the power supply can be much larger in amplitude. > During the 2KV Line-PE test it is not unusual to see a peak that > exceeds 3KV or more. This is a common phenomenon. > > Most power supply can handle the higher surge pulse, but some have > trouble with it ranging from restarting to blowing its guts out. > The problem seems to be getting worst. We are having a hard time > finding power supplies to pass under these conditions. > > Is there a simple solution to this problem? Are line – PE surge > suppressors the only solution? Are they allowed in products going > to Europe? I have heard that northern Europedoesn’t allow line to > PE surge suppression due to safety. Has this changed? Is there a > good over the counter device I can buy and drop in my product? > > If a surge suppressor is used, what requirements does it have to > meet? I hear gas tubes are a must. How about overcurrent protection? > Where would the fuse go? In the PE line? > > I have seen surge suppressors with UL and CSA agency approval, but > not with a European agency approval (I may just be looking in the > wrong place). Is this evidence they are not allowed in Europe? > > Thank you, > The Other Brian > _________________________ > > 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.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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
