That would be on the power input. Derek is looking at cleaning up the output. For his load, the LISNs will dominate the input impedance above about 10 kHz. If those batteries are in place in the test chamber the facility filters have been completely bypassed. Ken Javor
Phone: (256) 650-5261 > From: Ralph McDiarmid <ralph.mcdiar...@xantrex.com> > Date: Fri, 21 Aug 2009 09:35:54 -0700 > To: <EMC-PSTC@LISTSERV.IEEE.ORG> > Conversation: 28 volt Linear Power Supply > Subject: RE: 28 volt Linear Power Supply > > I've seen facility filters make some power supplies oscillate too. > > > Ralph McDiarmid, AScT > Compliance Engineering Group > Xantrex Technology Inc > > > -----Original Message----- > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken > Javor > Sent: Friday, August 21, 2009 9:12 AM > To: EMC-PSTC@LISTSERV.IEEE.ORG > Subject: Re: 28 volt Linear Power Supply > > Your facility EMI filters should provide 100 dB of insertion loss > (MIL-STD-220, 50 Ohm system). > > If that isn't enough, you can bypass the 28 Volt output with a couple > lead > acid car batteries. Then you can use a pair of 10 uF feedthrough caps > you > have laying around, and finally your LISNs. > > If all that doesn't do the job, you need to do some troubleshooting, see > if > some of the noise isn't common mode (not spec'd by manufacturer) and > build > your own cm choke. > > Ken Javor > > Phone: (256) 650-5261 > > >> From: Derek Walton <lfresea...@aol.com> >> Date: Fri, 21 Aug 2009 10:13:33 -0500 >> To: "EMC-PSTC@LISTSERV.IEEE.ORG" <EMC-PSTC@LISTSERV.IEEE.ORG> >> Subject: 28 volt Linear Power Supply >> >> Good morning folks, >> >> I have been requested to perform a conducted emissions test on a unit >> that draws up to 50 amps from a 28 volt source. >> >> I have a 300 amp supply and its a little too noisy being a switcher. >> >> Can anyone suggest a make/model that can do 28 volts at up to 50 amps >> thats either linear or super quiet please. Its very hard researching > how >> quiet supplies are. >> >> Many thanks, >> >> Derek Walton >> L F Research >> >> - >> ---------------------------------------------------------------- >> 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 >> <emc-p...@ieee.org> >> >> 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 <emcp...@socal.rr.com> >> Mike Cantwell <mcantw...@ieee.org> >> >> For policy questions, send mail to: >> Jim Bacher: <j.bac...@ieee.org> >> David Heald: <dhe...@gmail.com> > > - > ---------------------------------------------------------------- > 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 <emc-p...@ieee.org> > > 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 <emcp...@socal.rr.com> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher: <j.bac...@ieee.org> > David Heald: <dhe...@gmail.com> > > - > ---------------------------------------------------------------- > 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 > <emc-p...@ieee.org> > > 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 <emcp...@socal.rr.com> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher: <j.bac...@ieee.org> > David Heald: <dhe...@gmail.com> - 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 <emc-p...@ieee.org> 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 <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
