I disagree with a few statements made herein. Some differences are factual, but I am interested in general response on my last issue.
1) The military discarded the 5 uH LISN a long time ago. Commercial aerospace still uses it. In 1993 military adopted 50 uH LISN, essentially same as CISPR. 2) Why does Mr., Rao (or anyone else) feel that the LISN-based measurement is more accurate than a current probe measurement? I can see pros and cons to each, myself. ---------- >From: Praveen Rao <p...@tennyson.com.au> >To: "'Muriel Bittencourt de Liz'" <mur...@grucad.ufsc.br> >Cc: emc-p...@majordomo.ieee.org >Subject: RE: Doubt with conducted emissions measurement >Date: Tue, Dec 26, 2000, 5:26 PM > > > Hi Muriel and group, > Hope you all had a good Christmas. > > Yes, As Chris mentions, there can be problems with coupling/de-coupling > networks. > A classic example is the T-ISNs for conducted emissions on telecommunication > lines as per the new EN55022 : 1998 > The mains LISN however causing problems is not that common. > For Mil Stds tests current probes are normally used, but only for a few type > of tests (like DC and other leads), where the de-coupling device is still a > LISN or a 10 micro Farad feed through Capacitor. > Mains supply units are still tested with LISNs. But these are 5 micro henry > LISNs. And the test set ups are quite different. > The LISN tests are more reliable and repeatable than the current probe > tests. > > Happy New Year. The real new Millenium. > > Praveen rao > > -----Original Message----- > From: Muriel Bittencourt de Liz [mailto:mur...@grucad.ufsc.br] > Sent: Saturday, 23 December 2000 3:05 AM > To: Lista de EMC da IEEE > Subject: Doubt with conducted emissions measurement > > > > Hello Group! > > First of all, I wish a merry christmas and a happy new year for the list > members. > > Second, I'd like to solve a doubt. It concerns the methodology of > conducted emissions tests. > > Let's suppose a power electronic equipment (static converter) that has a > boost converter in the entrance that's used for power factor correction > (PFC). When I make a conducted emissions test, I plug the converter in a > LISN, then I plug the LISN in the outlet, this way (the classical way): > > Equipment => LISN => Outlet (Mains) > > Well, the LISN consists of a RLC network that has the purposes of: > - prevent that external interference from the mains contaminate the > measurement > - create a stabilized impedance (50 ohms) in the frequency range of > interest (150kHz-30MHz) to make results repeatable, from site to site. > > Ok, what I've said until here is well known and is present in every book > about this subject of EMC. > > My doubt is this: The LISN can't interfere in the functional operation > of the converter? Things like resonance, extra ripple can't occur? And, > imagining the worst scenario, can the LISN make my equipment not work > according to what's expected? > > Another thing I was thinking about is the fact that the military tests > os conducted emissions are done with a probe, and not using a LISN. > > I'm very curious about this subject because I was asked about this > question and I became very surprised, because I have never thought about > this. We are, generally, so interested in results that we forget to ask > the "basic questions" sometimes. > > Well, I think that's all. Thanks in advance for those who can help me. > > Best Regards > > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% > Eng. Muriel Bittencourt de Liz > EMC Testing and Troubleshooting > Group of Conception and Analysis of Electromagnetic Devices > Federal University at Santa Catarina > Florianópolis, SC, Brazil > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson: pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson: pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
