All so -- but I might also mention switching transients and unsuppressed high frequencies; I daresay semiconductor-switched phases could be a problem.
Cortland -----Original Message----- >From: "Wiseman, Joshua" <[email protected]> >Sent: Jun 29, 2020 8:17 AM >To: Cortland Richmond <[email protected]>, "[email protected]" ><[email protected]> >Subject: RE: [PSES] Conducted emission - AC line filters makes it worse > >I dealt with three phase a little bit at a previous employer. A couple items >that become important is whether it's a balanced load on all three lines and >if you're using a neutral conductor or not. We had options for with and >without neutral. > >Typically, we power the controls and single phase motors off of L1 and N or L1 >and L2 depending if we have a neutral. This often-caused higher currents on L1 >and if there was a neutral you could see higher leakage currents on it. > >Often our loads on L2 and L3 were three phase motors so filtering was not >always needed, so we would use a filter on L1-N or L1-L2 for the controls. In >rare cases where electronics/controls were used on other lines there would be >a filter on those as well. > >For products with resistive heating elements we did our best to balance the >load on each line. > >This never seemed to be a problem for us. > >Josh > >Joshua Wiseman >Systems Engineering >Staff Engineer, Product Safety/EMC >Ortho Clinical Diagnostics > > > >-----Original Message----- >From: Cortland Richmond <[email protected]> >Sent: Sunday, June 28, 2020 1:50 PM >To: [email protected] >Subject: Re: [PSES] Conducted emission - AC line filters makes it worse > >EXTERNAL SENDER: Verify links, attachments and sender before taking action > > > >It's three phase -- and you'll need a three-phase filter sharing one return >winding rather than three single phase filters. > >IMHO. > > >Cortland Richmond > > >-----Original Message----- >>From: Amund Westin <[email protected]> >>Sent: Jun 28, 2020 4:58 AM >>To: [email protected] >>Subject: [PSES] Conducted emission - AC line filters makes it worse >> >>A 3-phase product has three internal AC driven devices. >>The product fails on Conducted emission. When connecting AC filters to >>each internal AC driven devices, the emission gets even worse. >> >>Any clue about this phenomena? Is it some kind of impedance mismatch >>which derate the filters performance? >> >>BR >>Amund >> - ---------------------------------------------------------------- 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.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 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]>
