Hello Kris, As far as I know, there are no regulatory standards for audio emissions >from direct plug-in power supplies unless the noise reaches a limit where hearing protection is required. The sound levels requiring hearing protection would generally be far higher than you could achieve from transformer hum from this type of devices. Testing the noise level can be difficult because it will depend on structure supporting the outlet into which the supply is connected. The wall and structure supporting the outlet could serve to damp out the noise or to amplify it.
Consider this an issue for customer acceptance rather than a regulatory requirement. It may also be a reliability issue. The noise is being caused by something vibrating. Significant vibration could adversely affect components or component mounting. Ted Eckert APC-MGE http://www.apc.com/ The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC-MGE or Schneider Electric. The speaker does not represent APC-MGE's or Schneider Electric's official position on any matter. "Carpentier Kristiaan" <Kristiaan.Carpen To [email protected]> "John Woodgate" Sent by: <[email protected]>, [email protected] <[email protected]> cc 04/25/2008 06:04 Subject AM RE: Standards for accoustic noise John, The product is a Direct plug-in power supply, switched mode type. Best regards, Kris Carpentier Regulatory & Approvals From: [email protected] [mailto:[email protected]] On Behalf Of John Woodgate Sent: vrijdag 25 april 2008 12:33 To: [email protected] Subject: Re: Standards for accoustic noise In message <1f5308c5923f3b4daa51d189bf255006036b0...@edgmsmail01.eu.thmulti.com>, dated Fri, 25 Apr 2008, Carpentier Kristiaan <[email protected]> writes: >Products with transformers sometimes produce noise due to fact that >parts of the transformer are not fixed well or due to piezo-electric >effect. The acoustic level is rather low but can be annoying. Can >anyone point me to standards that describe this kind of acoustic >measurements and limits? There are some standards, but they are product-type specific. Which sort of product are you concerned with? Is this a mains transformer or one operating at a higher audible frequency? -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Murphy's Law has now been officially re-named The Certainty Principle John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
