Ken, The situation you describe sure sounds like the result of arcing. I would normally suspect that the relay contacts were the culprit if not for the repetition. If the noise is variable it may be caused by vibration. If possible, try to physically isolate the relays from the chassis to see if it goes away. A compressor can generate enough vibration to bounce some relay contacts. It is even possible that the vibration is causing some arcing problems inside of one of the motors.
Scott Lacey -----Original Message----- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Ken Javor Sent: Friday, January 25, 2002 1:09 PM To: emc-p...@majordomo.ieee.org Subject: broadband RE from AC induction motors Do any forum members have knowledge of a mechanism by which ac induction motors (two are fan motors, one a compressor motor) can generate broadband RE from 30 - 600 MHz? This is outside my experience. Are there perhaps degradation modes that result in arcing? The motors run off three phase 400 cycle power, 115 Volts rms phase to neutral. The control system is bang-bang, just mechanical relays making connections/disconnections based on temperature and pressure inputs. The rep rate of the BB noise is variable but around 10 milliseconds. Thank you. ------------------------------------------- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. ------------------------------------------- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
