Greetings Mr. Nute,
See below. Brian -----Original Message----- From: Richard Nute [mailto:ri...@ieee.org] Sent: Monday, January 26, 2015 1:52 PM To: Brian Oconnell; EMC-PSTC@LISTSERV.IEEE.ORG Subject: RE: [PSES] OSM decision What is the purpose of the MOV in this situation? As SPD, and to push me one step closer to madness What is the MOV Joule dissipation rating (can it dissipate the expected overvoltage)? NO - at least not by my calculations - and the MOV will, during some line/load conditions, probably start conducting a few mA during 'normal' operations Is the MOV protected by a fuse? Fuse on line input. And doubt that it would pass the G.8 stuff in 63268-1(but submittal is 60950-1) (An equipment d.c. bus is not likely to have high-voltage transients.) AC mains input to this equipment, so must assume the box will see at least 2500V -----Original Message----- From: Brian Oconnell [mailto:oconne...@tamuracorp.com] Sent: Monday, January 26, 2015 11:56 AM To: EMC-PSTC@LISTSERV.IEEE.ORG<mailto:EMC-PSTC@LISTSERV.IEEE.ORG> Subject: [PSES] OSM decision Was reviewing customer's construction where a 475V MOV was across the (floated) 420Vdc bus. Said this was bad idea, and they referred me to OSM/EE decision sheet 09/01 for EN60950-1:2006; which says ok to do whatever you want with a VDR on primary side that is not connected to mains. Can think of more than one SFC that would result in this combination of circuit configuration and component ratings making a mess. Any record of TC108 having affirmed this? Thanks, Brian - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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 <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
