For the sake of completeness and introduction, the signal coupled to a wire is a function of both field intensity and the electrical length of the fortuitous conductor. At vhf and below, we calculate the coupling of a field to a transmission line, and at higher frequencies we use a dipole model.
I would calculate worst case coupling to the fortuitous conductor in order to get filter ratings. At vhf and below, I would use the 1.5 mA per V/m assumption inherent in section 20, conducted rf susceptibility. Above the range of that requirement, I would use a tuned dipole model, with dipole effective height being lambda over pi, open circuit, and a source impedance of 73 Ohms. If you look at the circuit as either an open circuit load on that dipole, or a short circuit, you can get the max coupled potential and current. At 1 GHz, the dipole effective height is roughly 0.1 meter o-c, so 2000 V/m would couple 200 Volts open circuit, 2.7 Amps short circuit. If the threat is at higher frequencies, it just gets better. If the threat were at 400 MHz, we would use 2000 V/m * 1.5 mA per V/m and get 3 Amps of current on a cable. Ken Javor Phone: (256) 650-5261 From: Derek Walton <[email protected]> Date: Tue, 25 Jun 2013 22:49:15 -0400 (EDT) To: <[email protected]> Subject: High pulsed fields Hi All, I'm currently working on a DO-160 design that has pulsed fields between 1000 and 2000 v/m. I'm happy specifying filter parts for 200 v/m, but I'm curious if there are things I should take into account with the much higher peak fields, even though the duty cycle is low. Quantifiable suggestions are most welcome. Thanks, Derek Walton NCE #438 12790 Route 76 Poplar Grove, IL 61065, USA W: 1 815 986 6685 M: 1 815 566 5655 - ---------------------------------------------------------------- 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://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 <[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://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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
