I have seen the same kind of thing, but I believe there is a simple explanation. The input leads must meet CE102, but the output leads need only meet RE102, so they shield the output leads running to a dummy load in a control chamber. The fact that the customer can't shield the leads is another problem for another day. This doesn't happen when equipment is procured by an integrator and designed per the integrator's definition, but it is common with off-the-shelf gear.
for a son 3/26/03 1:38 AM, Doug Smith at [email protected] wrote: > > Hi All, > > Just wanted to put my 2 cents worth in. The same thing may be > happening in Mil-spec testing. Recently, I was at a client's site for > a purpose unrelated to this story. > > I noticed interference to the measurement I was trying to make on a > piece of equipment. The equipment had enough common mode current on > its leads to fail emissions, even though it was turned off! There was > a military battery charger for small batteries on their bench so I > connected my current probe to its power cord and noticed enough common > mode current to cause a 30 dB+ failure of emissions over a broad > frequency range. I would suppose the battery charger had been tested > to mil-specs. If so there is a problem here, even accounting for the > repeatability problems in mil-spec testing. > > Doug > > Grasso, Charles wrote: >> Hi Derek - Go Reds!! >> >> This is not a surprise to me. I have railed at much length a couple >> of years ago as to the latest FCC changes to the emissions >> qualification. I am sure you are familiar with it so I won't >> belabour the point. Fundementally the FCC PC emissions procedure >> has rendered the EMC discipline almost irrelevent. The new procedures >> coupled with the lack of enfocement makes it difficult to justify >> the increased costs of EMC design & test. It also makes the >> whole measurement uncertainty push ridiculous. After all >> if the procedures allow for prodcut that 20dB out of spec why >> bother with a couple of dB of error?? >> >> Lets give the emissions standards some teeth or eliminate it >> all together. >> >> Best Regards >> Charles Grasso >> Senior Compliance Engineer >> Echostar Communications Corp. >> Tel: 303-706-5467 >> Fax: 303-799-6222 >> Cell: 303-204-2974 >> Email: [email protected]; <mailto:[email protected]; > >> Email Alternate: [email protected] <mailto:[email protected]> >> >> >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] >> Sent: Tuesday, March 25, 2003 1:05 PM >> To: [email protected] >> Subject: OK, what's going on? >> >> Hi all, >> >> This e-mail has been prompted because of a number of things that >> have all come together. This may take a little reading, but please >> stick with it. >> >> Last note... this is not intended to pick on any individuals, or >> organization, but I do want to stir the pot. >> > ....... -- Ken Javor EMC Compliance Huntsville, Alabama 256/650-5261 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
