A couple of other thoughts: - Used to be that everyone thought X and Y cap's were hideously fire-hazardous. Perhaps the UL and CSA standards for line filters require a can (ie fire enclosure) around them, even if they are approved and even if the filter goes inside the outer (equipment) enclosure.
- Potting will allow you to meet reduced creepage and clearance that may be crucial in obtaining decent high frequency attenuation from the filter. Regards, Jim Eichner > Senior Regulatory Compliance Engineer Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. > -----Original Message----- > From: POWELL, DOUG [SMTP:doug.pow...@aei.com] > Sent: Wednesday, December 08, 1999 2:20 PM > To: emc-p...@majordomo.ieee.org; Treg Listserv (E-mail) > Subject: RE: Open Frame EMI Filters > > > 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).
