Single-turn loops are calculable, provided they are far from any metalwork, magnetic or not.
Rectangular loops are often easier to construct than circular. For these, the mag force H in the centre of the plane is 2D/(pi*A*B), where A and B are the sides in metres and D is the diagonal. With best wishes DESIGN IT IN! OOO – Own Opinions Only www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England -----Original Message----- From: Ralph McDiarmid [mailto:[email protected]] Sent: Tuesday, June 21, 2016 5:28 PM To: [email protected] Subject: Re: [PSES] Magnetic Field at 400 A/m But how to calibrate such a thing, to know how much magnetizing force is really being applied to the DUT ? Ralph McDiarmid Product Compliance Engineering Solar Business Schneider Electric From: Manny Barron [mailto:[email protected]] Sent: Monday, June 20, 2016 7:54 PM To: [email protected] Subject: Re: [PSES] Magnetic Field at 400 A/m Back in 1996 when I managed a 3rd party EMC test lab and when the IEC 1000-4-8 test became mandatory, I built my first magnetic field test setup using a "hula hoop" from Toys-R-Us. I wound the appropriate amount of insulated wire loops inside it, and added an appropriate power supply/transformer and some low resistance high wattage resistors. It worked great for small products and the 3 or 10 A/m test levels. Today there are more aesthetically appealing test setups available from various suppliers. Manny Barron Sr. EMC Engineer From: Ed Price [mailto:[email protected]] Sent: Monday, June 20, 2016 7:01 PM To: mailto:[email protected] Subject: Re: [PSES] Magnetic Field at 400 A/m Grace: I used to regularly test equipment to MIL-STD-1399, which had a DC magnetic field strength exposure requirement of 20 Oersteds, applied for 60 seconds. Since 1 Oersted is about 79.5 Amps/meter, that was equivalent to a 1600 Amp/meter field exposure. I did that with a Sorensen 50 ADC power supply, a 0.001 Ohm sense resistor, a DMM and a custom solenoid coil. The coil was wound with 163 turns of #12 solid wire, with a coil length of 711mm and a diameter of 590mm. This was adequate to expose a several unit high 19” rack-mount EUT. FYI, this antenna had an “antenna factor” of 2.217 Oersteds/Amp or 175.8 Amps/meter per DC applied Amp, with about 1.6 Ohms resistance. I built the solenoid coil using a “hazardous chemical disposal carboy” (think big strong plastic garbage can) with a cheap Harbor Freight appliance dolly bolted to one end. (Not only does this make the antenna easy to move, but it also greatly aids you winding that 1000 feet of #12 wire onto the carboy during several hours of Zen meditation.) Of course, if your EUT is smaller, then you don’t need such a large solenoid; I have a spreadsheet describing the design and performance characteristics of six solenoid coils I have built over the years. If anyone is interested, I have a description of the coil and the spreadsheet which I can send off-list. Ed Price WB6WSN Chula Vista, CA USA 1961 Amphicar 770 2001 Fleetwood Storm 31W 2008 Ford Explorer From: Grace Lin [mailto:[email protected]] Sent: Monday, June 20, 2016 4:18 PM To: mailto:[email protected] Subject: [PSES] Magnetic Field at 400 A/m Dear Members, Does anyone know which standard requires to have magnetic field evaluated at 400 A/m? Is there any commercial available instrument (loop) for the purpose? Thank you very much for your time and I look forward to hearing from you. Best regards, Grace Lin - ---------------------------------------------------------------- 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 <mailto:[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 List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <mailto:[email protected]> Mike Cantwell <mailto:[email protected]> For policy questions, send mail to: Jim Bacher <mailto:[email protected]> David Heald <mailto:[email protected]> ______________________________________________________________________ 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. To post a message to the list, send your e-mail to <mailto:[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 List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <mailto:[email protected]> Mike Cantwell <mailto:[email protected]> For policy questions, send mail to: Jim Bacher <mailto:[email protected]> David Heald <mailto:[email protected]> ________________________________ This message was scanned by Exchange Online Protection Services. ________________________________ - ---------------------------------------------------------------- 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]> - ---------------------------------------------------------------- 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]>
