CISPR does NOT require the Ground choke.. Thank you Charles Grasso (Capn Hook)
> ---------- > From: Muriel Bittencourt de Liz[SMTP:[email protected]] > Sent: Monday, December 07, 1998 3:46 AM > To: Helge Knudsen > Cc: 'EMC-PSTC - IEEE' > Subject: Re: Doubt on LISN utilization > > <<File: fig1.gif>><<File: fig2.gif>> > Hello Group, > > Thanks for all that answered my question. This question was due to some > measurements of conducted emissions that i've made. First, i've done > measurements with the Ground Choke in position "OUT". Then, the ambient > interference diminished a lot, as shows Fig. 1. Then i've switched the > ground choke to "IN" position, as shows Fig. 2. The standards i'm using > are based on European Standards ( CISPR 22, CISPR 15). Figs. 1 and 2 are > attached. > > So, when i try to do measurements, the spectra of conducted emissions > change according to switch position (ground choke on or off). > > My questions are: > > => Which emission measurement should i trust: the one with switch "IN" > or the one in "OUT" position (ground choke "in" or "out") > > => Could somebody make clear to me if CISPR requires this ground choke? > > => the ground choke is a must only in VDE measurements? > > I Think that's all... > > Thanks in advance! > > Muriel > > > > > Helge Knudsen wrote: > > > > Dear group, > > The use of ground choke in conducted measurements was specified in > > "Verfügerung 1046/1982" when testing to comply with VDE 0871 if the > > measured noise was closer to the limit than 5 dB. > > This second measurement must then also comply with the limit. > > The value of this ground conductor choke was specified to 1.6 mH. > > > > I believe the reason for this sophisticated measurement were required > > because the inductance in ground lead in really live may increase the > noise > > level with several dB's. > > I hope this clarified the matter. > > > > Best regards > > Helge Knudsen > > Jyske EMC > > Denmark > > [email protected] > > > > -----Original Message----- > > From: Cortland Richmond [SMTP:[email protected]] > > Sent: lørdag, december 05, 1998 05:43 > > To: Gary McInturff; ieee pstc list > > Subject: RE: Doubt on LISN utilization > > > > As I recall, when testing conducted emissions to VDE 0871, it was > required > > to observe noise in the two powered lines with the switch both open and > > closed, and use the higher result. Some power supplies would in fact > give > > different results if the ground was opened. > > > > An aside: I used to work at Tandy Computer's R&D. When Tandy quit > making > > computers (and I was laid off), I was able to buy a Rhode and Schwarz > LISN > > they scrapped -- for $25. It has the ground switch Muriel describes. > When > > I bought it for Tandy, it cost much, much more! > > > > Cortland > > > > --------- > > This message is coming from the emc-pstc discussion list. > > To cancel your subscription, send mail to [email protected] > > with the single line: "unsubscribe emc-pstc" (without the > > quotes). For help, send mail to [email protected], > > [email protected], [email protected], or > > [email protected] (the list administrators). > > --------- > > This message is coming from the emc-pstc discussion list. > > To cancel your subscription, send mail to [email protected] > > with the single line: "unsubscribe emc-pstc" (without the > > quotes). For help, send mail to [email protected], > > [email protected], [email protected], or > > [email protected] (the list administrators). > > -- > > ================================================== > > Muriel Bittencourt de Liz > INEP - Instituto de Eletronica de Potencia > Universidade Federal de Santa Catarina > Caixa Postal - 5119 > 88.040-970 - Florianopolis - SC - BRASIL > Phone: +55.48.331.9204 - Fax: +55.48.234.5422 > e-mail: [email protected] > Homepage: http://www.inep.ufsc.br > > ================================================== > --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
