Hi Everyone, thanks for the constructive comments so far.
I'm not really in a position to use batteries, my voltage spec is very tight at +- 0.5 volts. I have tried running through the facility filters, they are 100 amp rated, but I think a combination of that impedance and the LISN impedance is too much for the EUT starting current. It seems I can start the EUT with just the LISN's, but then I have too much noise from my power source. I swapped the room filters for some 10 uF caps, same ones that are called out in MIL std testing, and I almost get quiet enough. Ideally, I'd like to find a quieter source rather than try to filter..... Sincerely, Derek Walton Ken Javor wrote: > 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 <[email protected]> >> Date: Fri, 21 Aug 2009 09:35:54 -0700 >> To: <[email protected]> >> 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: [email protected] [mailto:[email protected]] On Behalf Of Ken >> Javor >> Sent: Friday, August 21, 2009 9:12 AM >> To: [email protected] >> 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 <[email protected]> >>> Date: Fri, 21 Aug 2009 10:13:33 -0500 >>> To: "[email protected]" <[email protected]> >>> 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 >>> <[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]> >>> >> - >> ---------------------------------------------------------------- >> 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]> >> >> - >> ---------------------------------------------------------------- >> 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]> >> > > - > ---------------------------------------------------------------- > 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]> > > - 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]>
