Re: EFT Failures..Help!
Hi Alex and the group, Often, one is very lucky to be able to fix such a problem while at the lab. Time there is best spent collecting data on the failure. Things like the actual failure voltage, cable positioning effects, and the such are important data that will make your device easier to troubleshoot in the lab. There are lots of troubleshooting techniques described on my website (www.dsmith.org). For instance, trigger a scope from the EFT generator and then use a magnetic loop (insulated paperclip will do) to trace the EFT current flow through your product. Once the exact path is known, often the solution is obvious. Because the EFT signal is (sort of) continuous and easy to trigger on, I have found EFT problems very easy to fix. Forget using any commercial scope probes though, they are useless in an EFT environment, too senstive to stray pickup. For products with metal enclosures, the balanced coaxial probe described on my website can measure signal voltages in the presense of ESD or EFT in equipment. I am working on a new balanced probe design that will work even better for this use as well as on signals past 1 GHz, but my first prototypes will not be ready for a few months, too late for your problem. Doug Alex McNeil wrote: Hi Guys, I am at an EMC test centre today and tomorrow. Unfortunately, my product failed EFT testing on the AC power port at 1KV. This is for various combinations of Line, Neutral and Earth (L, N, E, LN, LE, NE and LNE) My product is Class II, no Earth. It is supplied by an external power supply. This supplies SELV to my product. The power supply manufacturer has stated that his power supply meets EN61000-4-4 for 2KV and has emailed me this report to verify this. Has anyone got a quick solution to my problem so that I can implement here at the EMC test house? Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax: +44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.com --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. -- --- ___ _ Doug Smith \ / ) P.O. Box 1457 = Los Gatos, CA 95031-1457 _ / \ / \ _ TEL/FAX: 408-356-4186/358-3799 / /\ \ ] / /\ \ Mobile: 408-858-4528 | q-( ) | o |Email: d...@dsmith.org \ _ /]\ _ / Website: http://www.dsmith.org --- --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EFT Failures..Help!
I gotta agree with all that's said. I'm supposing you've tried the old cap across the input trick. Or, if the lab has a toroid laying around, you could probably wind up a common mode choke for experiment. Or, simply put in a line filter and see what happens. Mind the ratings, though. The power supply will have different criteria with Pass in 4-4 than your product. - Doug McKean --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EFT Failures..Help!
The power supply was probably not designed to _filter_ EFT signals, which can range up to 50MHz. Since power supplies are typically low frequency devices (as compared to 50MHz signals), it make sense that it was unaffected. Try using high frequency ferrite cores on the AC and DC lines. The cores may also may help reduce radiated emissions. On Mon, 22 Oct 2001 11:22:50 +0100, Alex McNeil alex.mcn...@ingenicofortronic.com wrote: I am at an EMC test centre today and tomorrow. Unfortunately, my product failed EFT testing on the AC power port at 1KV. This is for various combinations of Line, Neutral and Earth (L, N, E, LN, LE, NE and LNE) My product is Class II, no Earth. It is supplied by an external power supply. This supplies SELV to my product. The power supply manufacturer has stated that his power supply meets EN61000-4-4 for 2KV and has emailed me this report to verify this. Has anyone got a quick solution to my problem so that I can implement here at the EMC test house? Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax: +44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.com --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EFT Failures..Help!
Sounds to me that while the POWER SUPPLY keeps working, it does not sufficiently attenuate EFT presented to it that your product keeps working. It is POSSIBLE you might find a power supply that does, but unless you can control whose PS customers use, it may be smarter in the long run to fix the EUT. Either, of course, would result in passing the test. But if customers used a different PS later, you might find field returns with no apparent reason adding warranty costs in your rework center. The quick fix involves capacitors across the mains for differential, and mains to ground for common-mode, and might raise leakage. Less easy, but perhaps easier to live with, improve power filtering and device bypassing on the board so EFT does not completely discharge stored power. Cortland --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EFT Failures..Help!
At 11:22 22/10/01 +0100, Alex McNeil wrote: I am at an EMC test centre today and tomorrow. Unfortunately, my product failed EFT testing on the AC power port at 1KV. This is for various ^^^ My product is Class II, no Earth. It is supplied by an external power supply. ^^^ Hi Alex, Where is the AC power port on your product? Why are you testing a power supply that has been tested already? What do mean by failed EFT testing ? Did it reset, blow up. ? What is your product? :) Enci --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EFT Failures..Help!
Hope you're using more than one sample. I've been bit by having the one I brought to the lab not being in compliance. Anyway, make certain. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Alex McNeil alex.mcn...@ingenicofortronic.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Monday, October 22, 2001 4:06 AM Subject: EFT Failures..Help! Hi Guys, I am at an EMC test centre today and tomorrow. Unfortunately, my product failed EFT testing on the AC power port at 1KV. This is for various combinations of Line, Neutral and Earth (L, N, E, LN, LE, NE and LNE) My product is Class II, no Earth. It is supplied by an external power supply. This supplies SELV to my product. The power supply manufacturer has stated that his power supply meets EN61000-4-4 for 2KV and has emailed me this report to verify this. Has anyone got a quick solution to my problem so that I can implement here at the EMC test house? Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax: +44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.com --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
