Often wondered about this as well. The only connection I can see is that 0 is crossing from the negative direction and 180 would be crossing from the positive direction - or visa versa and the current is either leading or following the voltage potential but that doesn't really satisfy me either. Gary
From: [email protected] [mailto:[email protected]] On Behalf Of John Woodgate Sent: Thursday, October 19, 2006 12:20 PM To: [email protected] Subject: Re: IEC 61000-4-5 and phase angles In message <[email protected]>, dated Thu, 19 Oct 2006, Ralph McDiarmid <[email protected]> writes >Does anyone know of a sound technical reason why the IEC surge standard >calls for pulses to be applied at 0, 90, 180 and 270 degrees of the AC >voltage? If one tests at 0 degrees, isn't the 180 degrees phase-angle >redundant? Yes, but it would feel that its civil rights were infringed if it was left out. (;-) -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Swine wave - a waveform whose spectrum is exceptionally difficult to calculate. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
