Maybe they finally figured out it ain't true.... Some time ago, there were papers that referred to the power mains being 30 ohms in parallel with 30uF, or some such numbers like that..... Problem is, it varies widely, of course....
Best Regards, Michael Hopkins Manager, Customer Technical Center Control Technology Division Compliance Test Solutions Thermo Electron Corporation One Lowell Research Center Lowell, MA 01852 Tel: +1 978 275 0800 ext. 334 Mobile: +1 603 765 3736 [email protected] One Thermo, committed to integrity, intensity, innovation & involvement From: [email protected] [mailto:[email protected]] On Behalf Of Ralph McDiarmid Sent: Thursday, July 21, 2005 11:04 AM To: [email protected] Subject: RE: AC mains impedance Didn't the IEC publish a number for maximum expected impedance of the 50Hz public system in Europe? I recall something like 0.4+0.2j Ralph McDiarmid, AScT Compliance Engineering Group Xantrex Technology Inc. From: [email protected] [mailto:[email protected]] On Behalf Of Robert A. Macy Sent: July 21, 2005 7:22 AM To: John Woodgate Cc: [email protected] Subject: Re: It's too quiet John, I'm still digesting the thread regarding variability of that test. Here, I've measured effective impedance of the lines anywhere from 0.003 to 0.3 ohms. Once made a big difference in ground leakage test a for hospital product. The US govt paid for a study finding the "expected" impedance of AC mains over the spectrum of fundamental up to 1 MHz for residential, simple industrial, and medium sized industrial. Although very thick, copy makes interesting reading. There should be some way to predict the maximum "envelope" of the harmonics given a perturbation to the impedance. Or, simply, sweep the impedance over an expected range. Variability always suggests lack of controls. After all, science is in the business of verifiable/repeatable experimentation. Forgot, EMC is not a science. :-) - Robert - PS let us know if you don't get this one. On Thu, 21 Jul 2005 07:31:27 +0100 John Woodgate <[email protected]> wrote: > I didn't receive any messages yesterday, so I wonder if there is a > transmission problem. > -- > Regards, John Woodgate, OOO - Own Opinions Only. > Deadlines are 90% of deadliness. > http://www.jmwa.demon.co.uk Also see > http://www.isce.org.uk > > > 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 [email protected] > > Instructions: > http://listserv.ieee.org/listserv/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: > > Richard Nute: [email protected] > Jim Bacher: [email protected] > > 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 [email protected] Instructions: http://listserv.ieee.org/listserv/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: Richard Nute: [email protected] Jim Bacher: [email protected] 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 [email protected] Instructions: http://listserv.ieee.org/listserv/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: Richard Nute: [email protected] Jim Bacher: [email protected] 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 [email protected] Instructions: http://listserv.ieee.org/listserv/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: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
