The following comment is not based on any knowledge of the specs/standards cited in the OP, and is offered to elicit responses for the purpose of educating the undersigned in how these things work from a specsmanship point-of-view.
It seems to me that from a purely technical point-of-view, where the desired end result is controlling load-induced effects on mains power quality, that if a device has multiple modes of operation where it draws different amounts of current, then the harmonic levels for each mode need to be related to the fundamental current for each mode. Ken Javor Phone: (256) 650-5261 ________________________________ From: "Kunde, Brian" <[email protected]> List-Post: [email protected] List-Post: [email protected] List-Post: [email protected] Date: Wed, 21 Apr 2010 16:51:25 -0400 To: <[email protected]> Conversation: Harmonic Emissions Testing Subject: Harmonic Emissions Testing I am a newbie to Harmonic Emissions Testing. It is my understanding that the 61000-3-2 standard has hard harmonic current limits (2.3 amps 3rd harmonic for Class A) but the 61000-3-12 (2006 version) limits are a percentage of harmonic current referenced from the fundamental current. My questions have to do with what do you call the Reference Fundamental Current? Case in point, we have an instrument rated 30 amps, so we would apply the 61000-3-12 standard. This instrument has heaters that when they are warming up the entire instrument is drawing close to 30 amps. The harmonic currents at this point are relatively very low and would pass the test. But when the heaters come up to temperature and throttle back the fundamental current is only a couple amps and the harmonic current is now relatively high in percentage of the low fundamental current. If I use the maximum fundamental current my instrument passes and all is well. If I use the real-time fundamental current measured at different points throughout the test, then at times in the test it would fail. If an instrument could operate in different modes at different current levels, what do you use as the Reference Fundamental Current in the 61000-3-12 test? The maximum Fundamental Current of the instrument in any mode? In section 4.1a of the 61000-3-12 test, it says, “During the measurement of the reference fundamental current, the r.m.s. line current shall be equal to the rated line current Iequ stated by the manufacturer”. I’m not really sure what this means unless they are saying it is measured when the device is drawing maximum current. Any clarification you can give me would be most appreciated. Thank you in advance. The Other Brian _________________________ LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ 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]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ 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]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ 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]>
