Hi Carlos, The mains port is the actual connector on the test item, and during the measurement of conducted disturbance at the mains port, that port has to be connected to the LISN via a 1 m long mains cable or mains flexible cord. If the mains flexible cord provided by the maufacturer is in excess of 1 m, the excess cable is folded back and forth as far as possible so as to form a bundle not exceeding 0.4 m in length. Durng the measurement the test item is located so that the distance between the boundary of the item and the closest surface of the LISN is 0.8 m. All these words are more or less quoted from CISPR 22/1997 and with this test set-up the limits are given. Therefore the standard bodies has taken all this into account, and no correction factor is added.
Just my tw cents worth Venlig hilsen/Regards Niels Hougaard EMC Engineer, B.Sc.E.E BARCO AS/Communication Systems Phone direct: +45 39170815 Fax: +45 39170010 Mailto:[email protected] www.barco.com > -----Original Message----- > From: [email protected] [SMTP:[email protected]] > Sent: 19. januar 2000 16:06 > To: [email protected] > Subject: Mains port location > > > This is going to sound like a very naive question, and I almost don't want > to > ask it, but exactly where is the mains port? > > The question comes from some work I've been doing on our LISN. I've used > a > comparison noise emitter and a 1m mains lead (as required by BS EN 55022) > to > measure the insertion loss of the LISN. I then connected the CNE directly > to > the receiver and made a second measurement. At 150kHz, the results are > very > similar (0.5dB difference), but at 30MHz there is something like 5.5dB > difference between the direct measurement and the 1m-cable-to-LISN result. > > So, if the mains port is the actual connector on the test item, do I have > to add > a correction factor for the interference loss in the mains lead? Or is > the > mains port at the end of the 1m cable, in which case no correction factor > is > required. Or have the standards bodies taken all this into account, and > that is > why they specify a 1m mains lead? > > Any suggestions would be gratefully received:) > > Cheers, > > Carlos. --------- 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).
