Doug, There is no "requirement" for a case. The filter guy wants you to believe there is because that is how they make them. If, the filter can meet all of the safety and EMC requirements, it matters not how it is made. It could be just a bunch of components with their leads soldered together with no PCB, no encapsulant, no case. If it meets the necessary creepage, clearance, flammability, emissions, etc., requirements, then who cares how it is packaged?
If anyone can find such a requirement, please let me know. It would be a really good example unnecessary regulations. Scott s_doug...@ecrm.com ECRM Incorporated Tewksbury, MA USA -----Original Message----- From: doug.pow...@aei.com [mailto:doug.pow...@aei.com] Sent: Wednesday, December 08, 1999 5:20 PM To: emc-p...@majordomo.ieee.org; t...@world.std.com Subject: RE: Open Frame EMI Filters Importance: Low Hello once again, I have already received a number of replies to my query indicating that the metallic enclosure is required for low inductance coupling to the components or to prevent radiation between circuits within the product. This is not my question. Please remember that one of the criteria that I described for the open frame is the passing all applicable EMC tests. This means that the open-frame design that I propose meets both radiated and conducted emissions levels, without the metallic box. My questions deals more with why is the enclosure required if product passes the tests without it. In the past I have designed a few products with a simple PCB for emissions control. I compensated for the internal re-radiation problem. Recently I heard of a commercial EMI Filter company that says the enclosure is required and that the encapsulant is a requirement. I disagree. -doug ======================================= Douglas E. Powell Regulatory Compliance Engineer Advanced Energy Industries, Inc. 1625 Sharp Point Dr. Fort Collins, Colorado 80525 USA m/s: 2018 --------------------------------------- 970-407-6410 (phone) 970-407-5410 (e-fax) 800-446-9167 (toll-free) mailto:doug.pow...@aei.com http://www.advanced-energy.com ======================================= >> > >> > Hello group, >> > >> > For years I have used off-the-shelf and custom EMI filters >> with a fully >> > enclosed metal canister. Why is this enclosure required? Are there >> > specific provisions in the standards? My idea is to build >> up the filter >> > circuit on a printed circuit board and make it an integral >> part of the >> > power supply. >> > >> > I am currently looking at EN133200 which has certain seal >> tests but after >> > reviewing these, they all appear to be related to climatic or >> environmental >> > conditions. If the product passes these tests without the >> enclosure it >> > would seem that the product has passed, period. >> > >> > Alternatively I have considered removing the nomenclature >> "EMI filter" and >> > simply call it an input module, then evaluate it as a part >> of the overall >> > system. If it passes the EMC and Product Safety >> requirements, can I call >> > the job complete? >> > >> > Any thoughts? >> > >> > ======================================= >> > Douglas E. Powell >> > Regulatory Compliance Engineer >> > Advanced Energy Industries, Inc. >> > 1625 Sharp Point Dr. >> > Fort Collins, Colorado 80525 USA >> > m/s: 2018 >> > --------------------------------------- >> > 970-407-6410 (phone) >> > 970-407-5410 (e-fax) >> > 800-446-9167 (toll-free) >> > mailto:doug.pow...@aei.com <mailto:doug.pow...@aei.com> >> > http://www.advanced-energy.com <http://www.advanced-energy.com> >> > ======================================= >> > >> > --------- >> > This message is coming from the emc-pstc discussion list. >> > To cancel your subscription, send mail to majord...@ieee.org >> > with the single line: "unsubscribe emc-pstc" (without the >> > quotes). For help, send mail to ed.pr...@cubic.com, >> > jim_bac...@monarch.com, ri...@sdd.hp.com, or >> > roger.volgst...@compaq.com (the list administrators). >> > >> > >> >> >> >> >> --------- >> This message is coming from the emc-pstc discussion list. >> To cancel your subscription, send mail to majord...@ieee.org >> with the single line: "unsubscribe emc-pstc" (without the >> quotes). For help, send mail to ed.pr...@cubic.com, >> jim_bac...@monarch.com, ri...@sdd.hp.com, or >> roger.volgst...@compaq.com (the list administrators). >> >> --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
