Hi Jim and the group, Not sure what they mean by 6 dB insertion loss, but take a look at the article on my website at:
http://emcesd.com/tt2005/tt060105.htm The article presents data to show that more energy is sent to the AUX equipment than the EUT! If you want more stress, just turn the clamp around. I like to monitor the EFT current with a current probe so I can see what is happening. The Fischer F-33-1 is good for doing this although you may need a 6 dB or 20 dB attenuator in front of the scope. Compare the current from the CDN (if you can lower the current on your equipment) or use a similar piece of equipment as the EUT. Then put the current probe on the data lines and see what happens. One difference you can see from my data is that when coupled through the clamp, you tend to lose the long tail on the EFT waveform as compared to the CDN. In some instances that could make a difference. Doug Jim Eichner wrote: >>A lab we're using has an interpretation of EFT testing that never >>occurred to me. I'm interested in other people's understanding and >>opinions. Please feel free to point me to the archives if this has >>been discussed before. >> >>The generic immunity standard EN61000-6-1 calls out EFT on different >>types of ports, and gives the applied test level. For signal ports >>it's a 500V test using the clamp and for AC ports it's 1000V using a >>CDN. If the clamp has a 6dB insertion loss, as our lab claims, then >>the 500V spec in the standard results in application of 250V to the >>EUT cable. Presumably the authors of the standard know that and >>accounted for it. The CDN directly couples without 6dB of loss so >>presumably the authors said 1000V with the intent of the EUT cable >>actually seeing 1000V. >> >>So what do you do for an AC port that draws more current than the CDN >>available is rated for? >> >>The lab's answer is to use the cap clamp, but because of the 6dB >>insertion loss they doubled the generator setting to 2kV to obtain the >>1kV test that the standard calls for. Opinions? Comments? >> >>In 61000-4-4 it says that if the line current is higher than the >>specified current capability of the CDN you should use a 33nF coupling >>cap per figure 10, in which case the EUT would be powered directly >>from the grid and the EFT generator's connection to the EUT is via the >>coupling cap and appropriate grounding provisions (another question is >>what that looks like). I may end up insisting that the lab use this >>approach, but in the meantime I wanted to get the forum's opinion on >>the cap. clamp method discussed above. >> >>Thanks, >> >>Jim Eichner, P.Eng. >>Compliance Engineering Manager >>Xantrex Technology Inc. >>e-mail: [email protected] >>web: www.xantrex.com >>Any opinions expressed are those of my invisible friend. >>Confidentiality Notice: This email message, including any attachments, >>is for the sole use of the intended recipient(s) and may contain >>confidential and privileged information. Any unauthorized review, use, >>disclosure or distribution is prohibited. If you are not the intended >>recipient, please contact the sender by reply e-mail and destroy all >>copies of the original message. >> > > > ---------------------------------------------------------------- > 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/listserv/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: > > Richard Nute: [email protected] > Jim Bacher: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > > -- ___ _ 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: [email protected] \ _ / ] \ _ / Website: http://www.dsmith.org 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/listserv/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: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
