Don't know the answer to the DC issue -- one would think the same would apply for AC or DC lines.....
I can confirm that the simulator source impedances are: AC lines normal mode - 2 ohms; AC lines common mode (line to ground) - 12 ohms; I/O lines - 42 ohms for the combination wave, but 25 ohms when using the communications surge wave... For shielded lines, the test involves running a surge current along the shielded cable between two pieces of equipment -- in this case, the impedance is very low, since all would normally be at ground potential. For other I/O line and telecom line tests, the tests are performed between lines, or line to ground, in which case the impedances will be higher -- up to several hundred ohms.... Hope that helps... Mike Hopkins Thermo KeyTek -----Original Message----- From: Yow, Steve (IndSys, GEFanuc, NA) [mailto:[email protected]] Sent: Wednesday, October 10, 2001 10:00 AM To: 'EMC Post' Subject: Surge (1000-4-5) voltages & impedances Group, Can anyone help me understand why the generic immunity (61000-6-2:1999) has the same voltage level (500V) for both common mode and differential mode for DC power input where as for AC power input it uses two different voltages ( 2kV for common mode and 1kV for differential)?? I would think the DC requirement would look something like 1kV common and 0.5kV differential. (at least that is how table A.1 of 1000-4-5:1995 suggests). Is there any reasoning from someone one the TC for either the generic or test standard that could help explain. Also, could someone confirm that for power supply testing, differential mode uses lower impedance (2ohms) while common mode uses 12ohms. But for IO lines the impedance is 42 ohms no matter the coupling mode. True? For shielded communication lines, section 7.5 states surge applied to shield (common mode) with 2 ohm impedance, but Annex B states that a 42ohm impedance "represents the source impedance between all other lines and earth." I understand informative annexes are just that and do not impose test requirements like the normatives. I can accept 2ohms, but did not know if there might be an explanation as to why they would differ? Regards, Stephen Yow GE Fanuc Automation P.O. Box 8106, Charlottesville, VA 22906 PH: (804) 978-5915 Dial Comm: 292-5915 Fax: (804) 978-5102 Email: [email protected] Web Site: <http://www.gefanuc.com> ------------------------------------------- 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.
