Richard, What is the test plan for making and breaking under load? In general, power supplies take a little bit of time to start up, so making contact under load is not going to be an issue. UL has specified a 200 cycle disconnect test and all they are concerned with is condition of the contacts afterward. They do not specify how fast you have to plug the supply from the connector, so this could be a factor. Typically, they have a short signal pin that must be fully seated for the supply to operate. Once you start pulling the supply, the signal pin breaks first and shuts down the high current before those contacts break. The slower you pull, the less likely you will draw an arc. Or course, the fast you pull, the shorter duration the arc.
Regards, Glenn Lesmeister Product Regulatory Compliance Compaq Computer Corp. Tel: 281-514-5163 20555 SH 249, MS60607 Fax: 281-514-8029 Houston, TX 77070-2698 Pgr: 713-786-4930 [email protected] "I am empowered to do what makes sense!" -----Original Message----- From: [email protected] [mailto:[email protected]] Sent: Thursday, June 21, 2001 6:35 AM To: [email protected] Subject: RE: Hot Swappable Power Supplies ? We are currently evaluating a system with hot swappable power supplies and PCBs and here is what we have found needs to be checked: o Earthing pin makes first and breaks last o Primary and secondary power connectors are rated for make/break application o Access to hazardous voltages and energy hazards o Capacity of paralleled outputs may exceed energy hazard limits (we are adding PTCs on the backplane for each PCB which are also hot swappable) Richard Woods ---------- From: Richardson, William G [SMTP:[email protected]] Sent: Wednesday, June 20, 2001 5:50 PM To: 'Dan Teninty' Cc: '[email protected]' Subject: RE: Hot Swappable Power Supplies ? There must be a bleeder resistor (across the X caps) to make the AC input pins safe to touch once the supply is removed from the cabinet. If there are exposed voltage or energy hazards with the supply removed, there must be a restriction such that only trained personnel are instructed to do this OR a tool must be used to remove the supply. -----Original Message----- From: Dan Teninty [mailto:[email protected]] Sent: Wednesday, June 20, 2001 4:16 PM To: Emc-Pstc@Majordomo. Ieee. Org Subject: Hot Swappable Power Supplies ? Do any of my esteemed colleagues know of any specific requirements in 60950 (UL/CSA or EN) relating specifically to hot swappable power supplies? A search in the PDF version of UL/CSA 60950 reveals nothing specific when searching for "hot", "swap", or "power supply". A visual search of the TOC also reveals nothing specific. 2.6.5.4 deals with : Parts that can be removed by an operator Protective earthing connections shall make earlier and break later than the supply connections in each of the following: - the connector of a part that can be removed by an OPERATOR; - a plug on a power supply cord; - an appliance coupler. Compliance is checked by inspection. This is the most I could find that was related, and then it is referring to the AC side. Thought I would triple check with the collective brain trust to be sure. Appreciate any pointers to passages that I missed. Thanks, Daniel E. Teninty, P.E. Managing Partner DTEC Associates LLC Streamlining the Compliance Process 5406 S. Glendora Drive Spokane, WA 99223 (509) 443-0215 (509) 443-0181 fax ------------------------------------------- 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: http://www.rcic.com/ click on "Virtual Conference Hall," ------------------------------------------- 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: http://www.rcic.com/ click on "Virtual Conference Hall," ------------------------------------------- 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: http://www.rcic.com/ click on "Virtual Conference Hall," ------------------------------------------- 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: http://www.rcic.com/ click on "Virtual Conference Hall,"
