I read in !emc-pstc that [email protected] wrote (in <e9ff7eea38e6d311b941009027e78723030f3...@usysvmx01.ysv.flextronics.com> ) about 'Undervoltage/Overvoltage Effect on Household Appliances' on Fri, 6 Dec 2002: >I believe that the remarks below are valid only for undervoltage conditions. >In >overvoltage situations, any device will overheat and be damaged, regardless of >motor or power supply type, if the voltage is high enough.
Yes, of course. If it's high enough to do damage it will. Overvoltage can heat up some things and cool down others. >Some devices may shut >down safely because of internal over temp protectors or fuses. > >I know personally of a wall-mounted electric clock that overheated. The >plastic >case melted which dropped the clock to the floor where a fire started up the >wall. If someone had not been at home to put it out, the house could have >burned >down. The motor was a synchronous type which was "impedance protected", >whatever >that means. There was no indication of overvoltage or other extenuating >factor, >except possibly old age. Yes, Old age -> shorted turns. Overvoltage on an impedance-protected motor is most unlikely to cause catastrophic failure. Impedance- protected means that the winding will not burn up even if the rotor is locked. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! ------------------------------------------- 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] All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
