In message <[email protected]>, dated Tue, 24 Apr 2007, Brian O'Connell <[email protected]> writes:
>According to my wonderful copy of this wonderful standard (wonderfully >purchased from BSI), Much cheaper from Denmark (in English). http://www.ds.dk >the first dashed item indicates "Equipment with a rated power of 75 W >or less, other than..." OK, you have a copy of the standard. Many who should have, don't. > >And according to the good people at the EMC lab (an NB), the peak power >IS the rated power, no matter how small the duty cycle. Not 'no matter how small the duty cycle' . Look at 6.2.2, beginning at the third verse, er, paragraph; 'The value of the input power to be used for the calculation of limits... ' . The maximum value of the current, averaged over 1.5 s, is the current value in question. In your case, it is presumably 200 W/230 V = 0.87 A, since the 200 W mode lasts for more than 1.5 s. HOWEVER, that is 'for the calculation of limits' not 'for the classification and exemptions in Clause 7'. This is clarified in a future amendment, which has been delayed due to pressure of other work: Clause 6.2.2: Add the following sentence at the end of paragraph 5 ('The value of the power, … of the actual measured value.') : 'This value specified by the manufacturer is the "specified power", as used in clauses 5 and 7.' Rationale: Clarification. Clause 7: Replace 'rated power' (in each dashed item) by 'specified power according to 6.2.2'. Rationale: This improves consistency with clauses 5 and 6.2.2. NOTE that the above is DRAFT text and may change. >So, are they trying to get more business, or can I just use the average >power rating and not have to do this wonderful test ? No, you can't use the 'average power' averaged over the whole cycle time. But, as I said before, the product almost certainly passes without a PFC power supply (at least, if the heater isn't powered by the SMPS!). -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk There are benefits from being irrational - just ask the square root of 2. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex 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 [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
