Actually, the EFT test pre-dates the IEEE reference. IEEE included a reference to IEC 801-4 in the earlier IEEE 587 document, which has now become ANSI/IEEE C62.41 (now reissued as a 2002 document as a Trilogy: C62.41, C62.42, and C62.45). In the 70's, EFT tests were being conducted in Europe using spark gap generators, or what were called "showering arc" generators. The EFT burst as we know it grew out of this.
Unfortunately, neither the current IEC 61000-4-4 nor the older IEC 801-4-1988 contain any direct references for supporting material. In re-casting 61000-4-4 towards a revision, I looked for supporting documents but found only indirect information: a memo referring to work done by ABB in Sweden to define the transients; anecdotal information regarding the frequencies of "real" EFT to be in the MHz region, and a report from ABB Center in Mannheim of 1991 talking about the problems with EFT generators duplicating real field failures. I also have a New Work Item Proposal of 2000 from the Swedish National Committee. It contains data showing field measurements of EFT frequencies to be in the hundreds of MHz (vs. 2.5kHz and 5kHz in the current standard), and amplitudes of 1.5kV to 3.5kV. They propose burst frequencies from 400kHz to 25MHz and burst packets starting with low voltages at high repetition rates, ramping up to higher voltages at lower repetition rates. Some of this is now being dealt with in a proposed revision to IEC 61000-4-12, about to be circulated as a CDV, and will be reviewed by the SC77B Working Group 11 in the September meeting in Spain. Probably not useful info, but that's about it..... Best Regards, Michael Hopkins Manager, EMC Technologies Thermo Electron Control Technology Division EMC & ESD Simulation Solutions One Lowell Research Center Lowell, MA 01852 Tel: +1 978 275 0800 ext. 334 Fax: +1 978 275 0850 [email protected] One Thermo, committed to integrity, intensity, innovation & involvement From: Pat Lawler [mailto:[email protected]] Sent: Wednesday, June 04, 2003 10:55 AM To: EMC-PSTC Subject: Re: Electrical Fast Transient (EFT) and the Real World On Mon, 02 Jun 2003 16:51:47 -0400, "Stephen Irving" <[email protected]> wrote: >We are investigating the Electrical Fast Transient (EFT) test as detailed in IEC/EN 61000-4-4. I am looking for some experience/advise with this test. > >My understanding is that the IEC created this test to standardize fast line transient tests, such that a single repeatable test could be performed. As such, I am having a hard time finding information regarding the naturally occurring voltages and frequencies of these events. We are trying to expand the prescribed test into a "real-world, worst case" test. Does anyone have any experience or related documents that may help? > >Also, the test is prescribed to have a period of 300ms (15 line cycles at 50Hz). We are in the US, and are running the test at 60Hz (which does not work out to an even number of cycles - the beginning of the transient moves in time). Does anyone know if the test should be altered to provide a repeatable transient, or if there is a reason to leave it at 60Hz. > >I look forward to your comment - this is an interesting one! As always, thanks for your help. > >Best regards, >Steve Irving It looks like the EFT test was copied from an older IEEE document circa 1980. Take a look at specification IEEE C62.41, "Recommended Practice on Surge Voltages in Low-Voltage AC Power Circuits". Besides defining the waveshape of various transient waveforms (100kHz ringwave, Combination wave, 5n/50ns EFT, 10/1000us wave, 5kHz ringawave), it also has a section describing transients found in the United States. Pat Lawler <[email protected]> This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
