As the coupling mechanism to enclosure is Dominantly capacitive, this is a current source (Hi-imp) Combining your knowledge about the approximate value of the capacitance from wiring to enclosure ( say somewhere between 10-50pF) combined with value of frequencies will give you a Impedance for each frequency. As the polarity on the interferences on
the two capacitances (+ wire and - wire) are inverse, you will need to know the difference between the tow caps and use that cor the CM current. If both capacitances are equal, the CM current will be essentially zero. If the list were able to accept small images I would upload a picture..... Gert Gremmen Van: emc-p...@ieee.org [mailto:emc-p...@ieee.org] Namens rn...@san.rr.com Verzonden: zaterdag 13 december 2008 8:47 Aan: 'Ken Javor'; 'Untitled' Onderwerp: RE: Common-mode emissions from SMPS The question I have is: What is the Thevenin equivalent circuit looking back up the ground wire with respect to the line and neutral conductors? Is the source driving the current a current source or a voltage source or something in between? If in between, what is the source impedance (approximately)? And, what is the approximate value of the open-circuit voltage? Rich - 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...@ptcnh.net> 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...@ptcnh.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
