Even if it were found necessary to control EMC performance of a product over its service lifetime, I don't see how that could be done in practice. If it were common place that older electronic products became an RF nuisance, surely there would be evidence by an abundance of complaints to the authorities. Electrolytic capacitors and solder or mechanical connections do fail over time, but I suggest when they do the device likely also fails to function and is taken out of service. The apparent lack of legal control of EMC of products over their service life may simply indicate that none was warranted. _______________________________________ _____________________________________________
Ralph McDiarmid | Schneider Electric | Renewable Energies Business | CANADA | Compliance Engineer From: "Brian O'Connell" <[email protected]> To: [email protected] List-Post: [email protected] List-Post: [email protected] List-Post: [email protected] Date: 06/15/2010 10:24 AM Subject: Re: [PSES] EMC Performance Changing With Age Of Product ________________________________ "Obviously", you can get a single number from the direct use of equations that are based on the Arhenius model or inverse power law model, and there are several ways to statistically quantify lifetime performance such as MS217, MH338, and SR332. Feel free to do the math in your spare time. The FCC does not care if your box is old or new - if it makes an EMI mess and complaints are received, you have to fix it. For medical and vehicle, the risk analysis could consider this. My employer has various types of power conversion products operating over many environments. And electrolytic "cap dry out" is not on my list of top-ten failure modes - another 'urbane'(sic) myth. For the stuff that I work on, and for at least the last three years, the single stand-out component that has the largest failure rate increase is NOT a power component, nor is a component type that is connected to hi-V or hi-I, nor is it a component that operates at hi Tj. Which NONE of the above models predicted. Think design margin. Think HALT and HASS. Think ale and tacos. Never mind. Brian From: [email protected] [mailto:[email protected] <mailto:[email protected]> ]On Behalf Of Pawson, James Sent: Tuesday, June 15, 2010 1:11 AM To: [email protected] Subject: EMC Performance Changing With Age Of Product Hi folks, EMC performance of a product is likely to vary with age as the physical characteristics change e.g. caps dry out, metal junctions oxidise, etc. Obviously the product is designed with the intention of consistent compliance over the life of the product, but are there any requirements or guidance relating to preventing or controlling this change in EMC performance over time? Thanks James - 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 <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/ <http://www.ieee-pses.org/> Instructions: http://listserv.ieee.org/request/user-guide.html <http://listserv.ieee.org/request/user-guide.html> List rules: http://www.ieee-pses.org/listrules.html <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]> ________________________________________________________________________ This email has been scanned for SPAM content and Viruses by the MessageLabs Email Security System. ________________________________________________________________________ - 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]>
