Hi guys, Remember, this is just my opinion. I work for a manufacturer, not a test lab; so this is a side job (a HUGE side job); not my life.
For John: We do test the DC input of our rack-mount 48VDC products for conducted emissions. Many of our customers for these systems demand conducted emissions testing. The reasoning here is that these systems will operate from a DC "mains" which may operate many other products in the same rack or room. We use the same limits as for AC mains. However, we do not test the conducted emissions of the DC ports of our smaller products which run from wall-warts or bricks. For these products, we test the conducted emissions at the AC interface of the wall-wart or brick. For Sandy: When I test wall-warts for conducted emissions, I either plug them into the LISN directly or I use a short stub cable (about 6" long) made from Panel Components parts if I need to adapt the LISN output to a wall-wart with a non-US plug configuration. I then try to dress the wall-wart's cable in the configuration shown in the standard for dressing line cords. I'm sure there are other methods; but at least you have one opinion. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | > -----Original Message----- > From: CE-test - Ing. Gert Gremmen - ce-marking and more... > [SMTP:cet...@cetest.nl] > Sent: Wednesday, January 23, 2002 2:10 PM > To: John Stonier; emc-p...@majordomo.ieee.org > Subject: RE: Conducted emission testing for EN55022 > > Hi John, > > EN 55022:1994 does not speak about DC power supplies. Other > standards do. > Normally the appropriate measurements are done on the AC supply side > af any applied DC-power supply. > The pitfall is that a good RF attenuating in the supply may hide the > conducted emissions from your EUT, while another power supply > may lead to serious spectrum problems. > Your problem, because power supply manufactueres do not > specify RF isolation classes. > I suggest you to apply the test described using a basic transformer > rectifier combination + simple stabilization circuit (if required), > thereby minimizing attenuation and maximizing RF feedtrough. > Take care to bridge the rectifier diodes > with capacitors, otherwize thay might create interference themselves. > > Regards, > > Gert Gremmen, (Ing) > Ce-test, qualified testing > > ================================== > Web presence <http://www.cetest.nl/> > CE-shop <http://www.cetest.nl/ce_shop.htm> > /-/ Compliance testing is our core business /-/ > ================================== > > -----Original Message----- > From: owner-emc-p...@majordomo.ieee.org > [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of John Stonier > Sent: Wednesday, January 23, 2002 6:26 PM > To: emc-p...@majordomo.ieee.org > Subject: Conducted emission testing for EN55022 > > > Hi folks > > My test lab's current interpretation of EN55022 is that DC Mains > measurements are not required. Sections 5&6 specify measurements done > on mains ports, but do not specify whether it applies to AC or DC > mains. There is a reference in section nine that specifies conducted > disturbance is measured between the phase lead and the reference > ground, as well as the neutral lead and the reference ground. Does > anyone know whether DC measurements are required for this standard? > > John Stonier > << File: Gert Gremmen.vcf >> ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ 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: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
