This is interesting to me. I have tested many CE marked computer power supplies and they all met CE requirements at light loads up to about 50% loading, but somewhere over 50% loading the differential mode (dm) CE would go out of spec. This is ok if the typical power supply is derated 50% when it is used in a computer. So one question is how much do you load the power supply when you test it - you may want to load it just as your ITE product does.
Another issue is how much noise does your ITE product put back on the 5 and 12 Volt rails and how good a job does each power supply do of isolating the mains from rail ripple and common mode (cm) CE. That can also be assessed but it is more work. ---------- >From: am...@westin.org >To: emc-p...@majordomo.ieee.org >Subject: EMC and power supply >Date: Thu, Aug 16, 2001, 4:32 PM > > > Hi all, > > 1. We plan to EMC test a stand alone power supply (PS1) > 2. We have an IT product which has passed the EMC test. > 3. We want to remove the current power supply in the IT product and replace it > with the power supply (PS1) after it has passed the EMC tests. > > If power supply (PS1) pass the EMC test, do we have to make any re-tests on the > IT product ? I recall some talks about CE+CE not CE. > > Any suggestions ? > > Best regards > Amund Westin, Oslo/Norway > > -- > Get your firstname@lastname email for FREE at http://Nameplanet.com/?su > > ------------------------------------------- > 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: > http://www.rcic.com/ click on "Virtual Conference Hall," > ------------------------------------------- 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: http://www.rcic.com/ click on "Virtual Conference Hall,"
