Complicated situation --- Under open circuit conditions, you WILL see voltages on lines from the output of a surge coupler/decoupler that you don't think you should be surging simply because there are high impedance connections between the line, neutral and PE via filter capacitors and/or line-line protectors at the filter inputs. Surge PE IS connected to Neutral somewhere back at the building entrance as well.
Under load, what you get depends somewhat on the impedance of the thing you're testing --- if high impedance on all input lines, you might well see surge voltages on multiple lines; if low impedance, the surge current will go through the selected coupling lines.... A solution might be to get rid of the filter caps, but then you've got a problem meeting the requirement for keeping the surge voltage low back where the ac line is connected --- and you WILL have high voltages between lines now on the input side (probably close to where your scope is plugged in).... Nothing's simple.... Michael Hopkins International Channel Manager Thermo Fisher Scientific One Lowell Research Center Lowell, MA 01852 Tel: +1 978 275 0800 ext. 334 Fax: +1 978 275 0850 michael.hopk...@thermofisher.com From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Brian O'Connell Sent: Tuesday, June 05, 2007 3:15 PM To: emc-p...@ieee.org Subject: RE: Surge coupler anomaly As I have not seen this extreme (for a correctly constructed UUT) I would have to assume that none of my units were "completely normal". Perhaps the common-mode input chokes do not have well-matched windings ? I am very curious about this effect; if you can, pls advise on the root cause. luck, Brian From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of Bob Richards Sent: Tuesday, June 05, 2007 11:35 AM To: ieee Subject: Surge coupler anomaly In surge testing a product to 61000-4-5, we had a failure that could not be explained. So, we investigated and found that during a 2kv surge line-PE, we were seeing about 1.6kv line-neutral. The spec only requires 1kv line-neutral, and 2kv line-PE and neutral-PE. But when we surge line-PE we get much higher than the required 1kv line-neutral. I emailed the manufacturer of the surge equipment, and was told this is "completely normal". Has anyone else observed this kind of behaviour >from you surge equipment? Thanks in advance, Bob Richards, NCT. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
