Hi Chris, The power supply definitely should be decoupled by a standard CDN (f.a. CDN-T2) in order to couple the RF current from the calmp to ground. Then any standard power supply will probably do the job. This is exactly one of the major drawback (apart from needing higher power amps) that goes with the application of the EM-clamp. You might opt for CDN's for all cables to get better results on all tests. Note that the new EN 61000-4-6 allows for using only 2 CDN at a time.....
Regards, Gert Gremmen Approvals manager ====================================================== ce-test, qualified testing Member of EMC committee CENELEC/IEC + Independent Consultancy Services + Compliance Testing and Design for CE + Improvement of product quality and reliability + Testing services according to: Electro magnetic Compatibility 89/336/EC Electrical Safety 73/23/EC Medical Devices 93/42/EC Radio & Telecommunication Terminal equipment 99/5/EC Website: www.ce-test.nl Phone : +31 10 415 24 26 Fax : +31 10 415 49 53 ====================================================== From: [email protected] [mailto:[email protected]]On Behalf Of Chris Chileshe Sent: Wednesday, September 24, 2003 10:33 AM To: [email protected] Subject: DC PSU for conducted immunity testing to EN61000-4-6 Group, After quite a struggle to get a product through conducted immunity tests (clamp method), I finally discovered that the weak link in the chain was in fact my laboratory power supply which I have been taking along with me to a nearby test house. The problem remained undetected for a number of reasons, not least that I had used the same setup before at a different test house using their PSU ( Solartron ASxxx) and had better results, but mostly because we were using a small chamber dedicated to conducted immunity tests and using a camera to monitor the behaviour of the EUT behind closed doors and not keeping an eye on the PSU. When we eventually tracked the anomalous behaviour of the EUT to the PSU, we tried LISNs and a different PSU both of which improved the test results significantly but the outcome was still not good enough from a product compliance point of view. Question 1: Is anyone aware of a power supply suitable for this type of testing? The EUT draws a maximum of 30mA at 12VDC. I have been unable to find any Solartron PSUs on the web; probably long discontinued. Question 2: Has anyone tried to build a filter for this sort of thing and would this be the way to go? Best regards - Chris Chileshe - Ultronics Ltd - UK (O.O.O.) ________________________________________________________________________ This e-mail has been scanned for all viruses by Star Internet. The service is powered by MessageLabs. For more information on a proactive anti-virus service working around the clock, around the globe, visit: http://www.star.net.uk ________________________________________________________________________ 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
