In message <[email protected]>, dated Mon, 2 Apr 2007, Philo Beddo <[email protected]> writes:
>What about a situation where the rated line current is "much greater" >than the measured I_1 or I_ref? I don't know what you mean by 'I_ref'. There is no such term in the standard. If I_1 is much less that the rated current when the product is drawing rated current, that means that there is a huge harmonic content in the total current. No measurements shall be done under conditions where the total input current is much less than the rated current. >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? That is established in 4.1 a) by the reference to 4.2.1. You DO have a copy of the standard, don't you? If not, you are 'flying blind'. > >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? The particular committee involved is very concerned to resolve any such issues **as soon as possible after they are brought to notice**. The issue I mentioned, that some test houses were misinterpreting 4.1 and testing at far below rated current, was brought to notice only about 6 weeks ago. The standards procedures are not instantaneous, although they are much swifter than they used to be. > >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. No. Surely this is clear from 4.1 a) and b)? > >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? The actual situation is the reverse. There IS an established verification procedure for the IEC 61000-4-7 harmonics analyser, although more work is being done, but there is no established procedure for the IEC 61000-4-15 'flicker meter', and recent work has shown that different meters give different results under certain conditions. A project team has recently been set up to resolve this issue. -- 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 ______________________________________________________________________
