In message <[email protected]>, dated Mon, 14 Jan 2008, Brian O'Connell <[email protected]> writes:
>I have not been able to find fundamental construction information for >Y1-rated capacitors. Obviously, details may be commercially-confidential. But in principle, they consist of a metal film/dielectric sandwich, so designed that if the dielectric is punctured, the surrounding film evaporates during the discharge, thus isolating the puncture and preserving the insulation resistance minimally degraded. >I am also looking for failure mode and reliability info. They have to meet the relevant requirements of IEC 60384-14. > >What I can find, makes me feel neither warm nor fuzzy for use in Class >II construction. Y-capacitors are basically intended for connection line-to-earth. Since Class II products don't have an earth connection, Y-capacitors are not used for that purpose in them. So, if you want to connect a capacitor >from the mains side of a Class II product to the accessible side, you have to make sure that the reliability etc. are adequate on a case-by-case basis. You also need to ensure that touch-current requirements are met, which severely restricts the maximum value of capacitance. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. 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
