In article <f7e9180f6f7f5840858d3db815e4f7ad05fb9...@cms21.t-yuden.com>, Brian O'Connell <boconn...@t-yuden.com> writes
>Typically, I have always measured/calculated distortion PF using the >current waveform. What market segments tend to use/prefer the voltage >w/f ? Do you think that end-users of component power supplies prefer one >parametric over the other ? I tried to keep the explanation brief, but obviously it was too brief. In general, both the voltage and the current are distorted, and in-phase components of the voltage and current harmonics add to the true power. Equally, quadrature components add to the apparent power. If you just assume that the voltage is sinusoidal when it isn't, you do not get the right answers. > > >> If it only meets the Class A limits, it doesn't have much distortion >> power factor correction, if any. The displacement power factor depends >> on how heavily the power supply is loaded. > >I would appreciate if you could offer more commentary/insight on this >statement. Perhaps this is not based on power supplies that use active >PFC, where output loading has minimal influence on measured PF within >the unit's ratings. It isn't based on power supplies with active PFC. But such supplies normally meet the Class D limits if under 600 W active input power, so I inferred from the citing of Class A limits that your power supply didn't have active PFC. If it does, the power factor is likely to be very high, and not a matter of concern for your customer. But it would be unwise to guess a figure. -- Regards, John Woodgate, OOO - Own Opinions Only. The good news is that nothing is compulsory. The bad news is that everything is prohibited. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk 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 emc-p...@ieee.org 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: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.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.ieeecommunities.org/emc-pstc
