In message <[email protected]>, dated Fri, 18 Jun 2010, [email protected] writes:
>In desperation the motor was bolted to the bench horizontally to begin >looking into what could be happening and all noise ceased. It was >rotated vertically and all noise returned. Just the motor? If so, is the motor intended for vertical mounting? I suppose so, but that does require a thrust bearing at the lower end. It sounds as though the bearing is carrying current (due to stray magnetic field) and when under thrust the contact is intermittent. Try putting conducting grease in the bearing. Make sure it really IS conducting, not just 'graphite grease' or 'copper-loaded grease', which may or may not conduct. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK I should be disillusioned, but it's not worth the effort. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ 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]>
