I read in !emc-pstc that Dave Spencer <dspen...@dsl-only.net> wrote (in <185530-22003324161424...@dsl-only.net>) about 'Power Factor Correction' on Tue, 4 Mar 2003: >I am looking for some input on your experience with PFC as it relates >to testing (EN61000-3-2 and EN55022). Has anyone using an AC-AC >external transformer in the 15-20 Watt range experienced difficulty >passing, e.g. no PFC?
Well, you don't say what the transformer is feeding! Assuming it's a bridge rectifier with a fat filter capacitor, the resistances of the transformer windings are usually sufficient to make the rectifier conduction angle exceed 65 degrees, which should be sufficient to meet the Class D limits. BUT those limits doesn't apply below 75 W anyway! One might guess that you haven't read the standard, and have thus been worrying over a non-problem. OTOH, one might, of course, be wrong in an entirely unexpected direction. -- 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: davehe...@attbi.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
