Conflict of Interest Notice: My employer makes component power supplies. PFC data should be available. It should be an important part of the vendor's DVT.
Component power supply PF can be affected by many variations in the input power quality, output load(s), and input voltage. In any case, there is no reason that a modern off-the-shelf unit should be < 0.97 over its input ratings. There is no reasonable way to "infer" PF. If the unit uses active PFC, the PF should be pretty good, for other than SFC operations. Compliance with -3-2 can only be indicated for a particular configuration of a particular end-use item. A component power supply is not an end-use system. Of course, PFC, safety and performance costs $$, so if you buy a cheap unit, you had better repeat more than just the EMC tests... luck, Brian -----Original Message----- From: Gary McInturff [ mailto:[email protected]] Sent: Monday, October 11, 2004 10:54 AM To: [email protected] Subject: Power Factor correction Ladies and Gentlemen I think I may be stuck between a rock and a hard place. We have a new project that is, for all practical purposes a custom design for a client. We purchase a supply that indicates compliance with EN61000-3-2 harmonics. Our customer wants a more quantitative number. Is it 90% PFC, 95% etc. I can't tell that from the spec sheet and quite frankly at this point I can't lay my hands on a power supply yet and obviously we haven't gone to test yet with this in our equipment so I don't believe I have any way of determining this (not sure that I could tell from the conformance test anyway - can I?) When I call the power supply manufacturer, I can't directly address the design engineer and all they can tell me is that it meets the requirements for Class A waveform. Am I overlooking something here in the datasheet? Is there anyway to infer what what the PFC % is? Gary ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: [email protected] Scott Douglas [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
