Hi, A very descriptive device is presented in the following book:
Power Line Filter Design for Switched Mode Power Supplies. By Mark Nave. It is out of print, and if you see a copy for sale, it's worth buying. He also took out a patent for his device under the following no: US Patent No: 4,849,685 Dated Jul 18, 1989. If you want a more detailed description I recommend you buy a copy from the US Patent office. 3 US Dollars for an internet download. Not free, but cheap enough to make it worth buying the PDF version. His device basically cancels out the DM noise, then you design a filter for the CM noise. Fit the CM filter, and remove the device, then measure again and the difference will mostly be the DM noise making it easier to design the filter. Simple really and from the looks of the design cheap!( the parts you probably have laying around in your workshop!) I keep meaning to make one but have yet to get around it. Oh yes, symmetry is important and you will need a LISN with two outputs. Enci At 00:37 05/02/02 -0300, you wrote: > >Hello Group, > > >I am looking for a device that will differentiate the dominant component >(either >common-mode or differential-mode current) in the total conducted noise >emission >current of a product measuring through its' power cord using a LISN. > > >This device can be called "common/differential mode current separator". In >conducted >noise emission measurement, both common-mode and differential mode noise >current are measured by LISN and the LISN can't tell which mode is the >dominant >current. > > >I came across a paper by Clayton Paul and Keith Hardin which explain the >usefulness of a separator like this that would identified the dominant >current >from the total current. Hence, the correct capacitor value(either X-caps or >Y-caps) can be changed accordingly so to reduce the overall conducted noise. >The book by Clayton Paul "Introduction to Eletromagnetic Compatibility" has >also mention about this device. > > >I have contacted a few persons trying to look for the person who have >actually >built this separator himself and I am also looking for any vendor who have >this >product for sale. So far, my effort has yield no results. > > >Can anybody point me to the right person so that i can try to built this >separator myself. Any other suggestion and comments are greatly appreciated. > > >Best Regards, > >************************************************************** > >Muriel Bittencourt de Liz > >Ph.D. Student > >Federal University at Santa Catarina > >Florianópolis, SC > >Brazil > > > > >------------------------------------------- >This message is from the IEEE EMC Society Product Safety >Technical Committee emc-pstc discussion list. > >Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > >To cancel your subscription, send mail to: > [email protected] >with the single line: > unsubscribe emc-pstc > >For help, send mail to the list administrators: > Michael Garretson: [email protected] > Dave Heald [email protected] > >For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > >All emc-pstc postings are archived and searchable on the web at: > No longer online until our new server is brought online and the old messages are imported into the new server. > > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
