I read in !emc-pstc that Brian O'Connell <boconn...@t-yuden.com> wrote (in <f7e9180f6f7f5840858d3db815e4f7ad1f2...@cms21.t-yuden.com>) about 'CE for components?' on Thu, 3 Jul 2003:
> "Pre-compliance" EMC testing of component power supplies is > problematic. My employer has directed a lot of resources helping > customers fix their noise problems. And occasionally, some of our > (more clever) customers give us EMC test reports that indicate much > better performance than when the installed power supply was tested > as stand-alone device... > > There is a reason that I cannot list any EMC standards for > component power supplies on the D of C; because the test has no > meaning until the unit is installed in the end-use device. There is a product EMC standard for power supplies - IEC 61204-3. I'm not sure of its status in Europe. > > Conversely, there are valid reasons that I can list Product Safety > standards on the D of C; because LVD standards define re-producible > tests that clearly indicate performance upon end-use abuse. > > There was a CTL meeting report (Helsinki, October 2000) that > indicated EMC test data was re-producible internally, but much less > so from one lab to another. This variation of EMC test data seems > to be "expected", but is never acceptable for Product Safety test > data. Go figure.... It's very simple, really. Tests for product safety are not accepted into standards unless they give reproducible results. The limitations imposed by the laws of physics are such that many EMC tests, especially those involving radiate energy, have poor reproducibility of results. But better tests are simply not available. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
