I believe that 61000-3-3 Annex A (I don't have a copy to hand) and IEC 725, specify the line impedance to be used as:
Standard Reference Impedance Mode: (0.40+j0.25) Ohms ±3% at 50 Hz Dave C. From: [email protected] [mailto:[email protected]] On Behalf Of Richard Schumacher Sent: 21 July 2005 16:40 To: [email protected] Subject: RE: AC system impedance Presumably these are at 50 Hz only? > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Ralph McDiarmid > Sent: Thursday, July 21, 2005 10:32 AM > To: [email protected] > Subject: RE: AC system impedance > > > I have a number from an old, partial copy of "Rationale for > Emission Limits" from SC77A/WG01. > > Standardized Reference impedance: > Single phase 0.4+j0.25 > 3-phase line 0.24+j0.15 > 3-phase neutral 0.16+j0.10 > > Apparently the investigations made at the time across Europe > concluded about 95% of the line impedances measured would not > exceed those values. > > Ralph McDiarmid, AScT > Compliance Engineering Group > Xantrex Technology Inc. > > -- > -----Original Message----- > 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 - > 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 ********************************************************************** IMPORTANT NOTICE The information contained in this e-mail is confidential. It may also be legally privileged. It is intended only for the stated addressee(s) and access to it by any other person is unauthorised. If you are not an addressee, you must not disclose, copy, circulate or in any other way use or rely on the information contained in this e-mail. Such unauthorised use may be unlawful. If you have received this e-mail in error, please inform Racal Instruments Group Ltd. immediately by emailing [email protected] or phoning +44 (0)1202 872800 (ask for the I.T. Dept.) and delete it and all copies from your system. www.racalinstrumentsgroup.co.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
