Mr Woodgate, thank you for your response: What about a situation where the rated line current is "much greater" than the measured I_1 or I_ref? Is I_1 that is used to calculate the limit(s) based on the highest observed value OR the average of the 1.5 second smoothed values? If there are areas of contention in the standard, don't you think it's the obligation of the standards committee to sort that out before the companies affected spend significant sums of money abating a non-issue? Is it a requirement to test an EUT in stand by? Such as a printer or printing press? In the stand by mode the I_1 will be low, but the harmonic content could be very high. My question about verification of test equipement is really a soft jab at the few equipment manufactures out there. With Flicker a test lab can verfify that Pst and Dmax are met. There is nothing as obvious for Harmonics. Any suggestions? Kind regards Ashworth
John Woodgate <[email protected]> wrote: In message <[email protected]>, dated Mon, 2 Apr 2007, Philo Beddo writes: >How do you define I ref? >Stand by testing on very high power equipment, what I-ref is used? I suppose that by 'I ref', you mean I_1 as defined in 3.11. You do not test under stand-by conditions. This is a known misinterpretation of the standard and there is a proposal to amend the wording to clarify it. But 4.1 a) is really quite clear: '...the r.m.s. line current shall be equal to the rated line current I_equ stated by the manufacturer.' There is a small point there that needs attention: it may not be possible to achieve rated line current with some samples of the product. The last paragraph of 4.1 deals with variations in I_1, but there needs to be some text to say that if you can't get rated line current with your sample, you use the highest current you can get. Or something: the proposal has only very recently been submitted at it won't be discussed until June, unless it generates an e-mail storm. >How would a test lab "verify" that the equipment meets the requirements >of EN61000-4-7 without being a cal la? Is there an easy >verification? Where do you find 'verification' in the standard other than in 4.2.2? Actually, 4.2.2 is not entirely correct: the requirement is about setting a long enough test observation period (4.2.6). This came to light as a result of an amendment to IEC 61000-3-2 and may be dealt with at the same time as the clarification. If you mean Clause 7, 'verify' there means 'confirm the values for emissions given in the manufacturer's test report'. >Without sending the unit to NPL for a certification. > The standard certainly doesn't mean that. -- 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 _____ TV dinner still cooling? Check out "Tonight's Picks" <http://us. d.yahoo.com/evt=49979/*http://tv.yahoo.com/> on Yahoo! TV. - ---------------------------------------------------------------- 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 ______________________________________________________________________
