Kevin The limits for class A are absolute, independent of the input power to the equipment. The class D limits are proportional to your input power, (1st column) up to the maximum permissible harmonic current given in the second column of the class D table (which is the same as class A)
e.g. A class D device with an input power of 500W can have a maximum 3rd order harmonic of 500 x 3.4mA/W = 1.7A a 1000W device can have a maximum 3rd order harmonic of 2.3A as 1000 x 3.4 = 3.4A which is greater than the absolute limit of 2.3A. Or more simply, for class D always use the lower figure from the two columns. Hope that helps Marry x-mass Kevin Newland wrote: > Hello All, > > I have been told that on EN61000-3-2 (harmonic > standard)the class A limit is much easier than class > D, but when I look at the two tables, they look almost > identical. Could someone explain to me the difference > between the two limits (A & D) and also which of the > two limit column in the class D table I should be > using? > > Thanks and have a great holiday. > Kevin > > __________________________________________________ > Do You Yahoo!? > Yahoo! Shopping - Thousands of Stores. Millions of Products. > http://shopping.yahoo.com/ > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson: pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org -- Andrew Carson - Product Safety Engineer Xyratex Engineering Laboratory Tele 023 92496855 Fax 023 92496014 ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
