Hi Ted and the group, In your response below"
"The coupling clamp should not create significant radiated noise." I wanted to add a war story. Although the radiated energy is much smaller than the coupled energy, I successfully burnt out a wireless mike (base unit). The clamp was in the back of a room about 20 or 25 feet away, the mike receiver along one wall about mid-way between me and the clamp. I had a shorted scope probe connected to a wire in the front of the room to show the intensity of the radiated field. As the generator was turned up, the signature chirping noise became evident in the mike base unit output to the PA amp. At one point, with lots of noise in the scope probe, the mike receiver went dead! Quite a coincidence I would say, but I did not want to test the hypothesis with another unit. Doug [email protected] wrote: >Hello Grace, > >I do not believe that there is a specific separation requirement between >the EFT generator and the coupling clamp. I have a system from Keytek that >came with a 0.5 m cable to connect the generator and the clamp. If >anything, I find supplied cable to be too short for my needs. From what I >know, the capacitive clamp should not cause interference with the EFT >generator even if they are in close proximity. > >The coupling clamp should not create significant radiated noise. In this I >mean that the noise radiated by the clamp will be far less than that >coupled into the EUT through the cable under test. There should not be a >significant problem with the test if the EUT is less than 0.5 m from the >clamp as long as you have the 0.5 m length of exposed cable that is >specified. > >I will admit that I am not an expert in EMC measurements. I have been >working with susceptibility testing for about eight years, but it only a >fraction of the work that I perform. I am posting my opinion (and it is >only an opinion) because I have not yet seen a response to your inquiry. I >would like to encourage the more experienced EMC professionals to let me >know if my though process is sound on this issue. If I am wrong, let me >know; I am eager to learn more about the rationale behind the test >procedure. > >Ted Eckert >American Power Conversion/MGE >http://www.apc.com/ > >The items contained in this e-mail reflect the personal opinions of the >writer and are only provided for the assistance of the reader. The writer >is not speaking in an official capacity for APC-MGE or Schneider Electric. >The speaker does not represent APC-MGE's or Schneider Electric's official >position on any matter. > > > > "Grace Lin" > <gracelinnj@gmail > .com> To > Sent by: [email protected] > [email protected] cc > > Subject > 10/29/2007 02:24 EFT Setup > PM > > > > > > > > > >Dear Members, > >I have two questions and appreciate your inputs: > >1. Is there any clearance distance/requirement between an EFT generator and >a capacitive coupling clamp (ccc)? > >2. Is there any clearance distance/requirement between EUT and a capacitive >coupling clamp (CCC)? From Figure 1 of IEC 61000-4-4, the cable length >between the capacitive coupling clamp and the EUT "should be 0.5m +/- 0.05 >m". Does this mean the distance between EUT and CCC should also be 0.5m? > >We built a 4ft x 8ft table with the same size of metal sheet (reference to >ground reference) on top of it. I would like to place an EFT generator, >CCC, and EUT on top of the table. > >Thank you for your time and look forward to your help. > >Best regards, >Grace Lin >- ---------------------------------------------------------------- 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/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] > > >All emc-pstc postings are archived and searchable on the web at: > > >http://www.ieeecommunities.org/emc-pstc > >- >---------------------------------------------------------------- >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/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] > >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. 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