Hi Group,
Proposals are on their way to specify both transfer attenuation (first) and input CM impedance of those clamps (later) The radiation properties of the exposed wire will vary widely depending on the CM load impedance. The attenuation characteristic is to isolate auxilary wire (and signal) from the test setup. Both will be published as an Amendment on CISPR 16 document. A controllable impedance clamp system can be constructed using a current clamp system with variable load . (like current clamp/transformer) The first 1-5 rings can be loaded with a screened wire that terminates into a variable ( or fixed) impedance. Target CM impedance will probably be 150 Ohm to be transferred to the load. This has best impact in the lower frequency range. High loss ferrite will do better as low loss ferrite. Attenuation is just a matter of quantity of rings. Regards, Gert Gremmen Manager Ce-test, Qualified Testing ce marking and more .. EMCD LVD R&TTED MDD MD www.cetest.nl Electrical / Electronic Equipment From: [email protected] [mailto:[email protected]]On Behalf Of Gordon,Ian Sent: Wednesday, January 29, 2003 11:51 AM To: [email protected] Subject: RE: EN55022:1998 + A1:2000 All I can see that my manager would prefer to use Neven's approach - it is probably much cheaper than buying clamps. However, does anybody have any practical experience of this? A reply from an accredited test house would be welcomed! Thanks Ian Gordon From: [email protected] [mailto:[email protected]] Sent: 29 January 2003 05:22 To: [email protected] Subject: Re: EN55022:1998 + A1:2000 Instead of paying big bucks for the clamps (I am not sure what the price is, but I'm sure it is too much anyway :), why not buying a bucket of ferrite doughnuts that can be used over cables. Or, when possible, building in-line adapters out of sections of cables (maybe 1m long) and lining them up with ferrites. I'd select a combination of ferrites to cover 30 MHz to about 300 MHz. The high frequencies will be radiated anyway by the segment of the cables close to the DUT. Taking a little more thorough approach, I'd check the impedance with the lineup fixed over a defined height above a GND plane. (Not sure if that would make a big practical difference.) Neven > > A1 to EN55022:1998 requires the use of ferrite clamps on all cables leaving > the table-top EUT for a connection outside the test site. Are there any > other manufacturers of these clamps other than Fischer Custom > Communications? > > Richard Woods > Sensormatic Electronics > Tyco International _____________________________________________________________________ This e-mail has been scanned for viruses by the WorldCom Internet Managed Scanning Service - powered by MessageLabs. For further information visit http://www.worldcom.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: [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
