IMO, a near field probe gets you back to where Bill Owlsley was at: you are X dB over the limit on the test site, so you wave a probe around and look for X dB reduction in signal from whatever change was made, hoping the probe picks up something proportional to the RE field at three or ten meters.
Whereas with a current probe, even without any site testing, a common mode conducted emission (CMCE) limit can be determined based on the three or ten meter RE limit, and then the design work is done on the cable before any testing at any site. Ken Javor Phone: (256) 650-5261 From: "McDiarmid, Ralph" <ralph.mcdiar...@schneider-electric.com> Reply-To: "ralph.mcdiar...@schneider-electric.com" <ralph.mcdiar...@schneider-electric.com> Date: Thu, 14 Jan 2016 14:20:33 -0800 To: <EMC-PSTC@LISTSERV.IEEE.ORG> Subject: Re: [PSES] Current probe for CM currents Would a Near Field probe be a better choice? ____________________________________________________________________________ ___ Ralph McDiarmid | Schneider Electric | Solar Business | CANADA | Regulatory Compliance Engineering From: Ken Javor <ken.ja...@emccompliance.com> To: EMC-PSTC@LISTSERV.IEEE.ORG, Date: 01/13/2016 01:22 PM Subject: Re: [PSES] Current probe for CM currents A current probe measures the net current on the conductor within its opening. The impedance of the circuits attached to that conductor may affect how much current flows through the conductor, but not the measurement thereof. Ken Javor Phone: (256) 650-5261 From: Amund Westin <am...@westin-emission.no> Reply-To: Amund Westin <am...@westin-emission.no> Date: Wed, 13 Jan 2016 18:48:23 +0100 To: <EMC-PSTC@LISTSERV.IEEE.ORG> Subject: [PSES] Current probe for CM currents Planning to do some EMI troubleshooting with a «homemade» current probe. Probing a lot of cables inside a rack and try to find the source. Will make a current probe by a ferrite core (two halves, a few turns wire and coax plug) as many EMI experts have posted on the web and on this forum. Then find the Zt[dBohm], so make a measurement on a cable and verify the readings on the spectrum. But when clamping on the current probe, which is a ferrite, does that change the cable impedance and therefore actually changes the real current flow, so my reading will not be true? ... or am I missing some fundamental theory here? ... #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 <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html <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/ <http://product-compliance.oc.ieee.org/> can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ <http://www.ieee-pses.org/> Instructions: http://www.ieee-pses.org/list.html <http://www.ieee-pses.org/list.html> (including how to unsubscribe) <http://www.ieee-pses.org/list.html> <http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html <http://www.ieee-pses.org/listrules.html> For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com> ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. ______________________________________________________________________ - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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