Good People of PSTC: I am attempting to comply with both the letter and spirit of 60950:2000, cl 5.2. Note that 5.2.2 allows for separate testing, according the type of insulation required. When testing a (class 1) power supply, the withstand level for primary to chassis is Basic; and for primary to secondary is Reinforced. Typically, I will apply approx 2500vdc for Basic and 4300vdc for reinforced. But to pass primary to secondary test, 60950 says that I can allow for following:
"care is taken that the voltage applied to the reinforced insulation does not overstress basic...". Also "to avoid damage to components or insulation which are not involved in the test, disconnection of ICs or the like and the use of equipotential bonding are permitted." For Pri/Sec testing, the screw connecting the Y-caps to the chassis is removed, insulation is inserted between the screw insert and chassis. A (new) agency engineer says that inserting a piece of insulator defeats the purpose of the test. For class 1 construction, it is just not possible for me to pass 4300vdc test levels without inserting my little piece of valox, unless I physically remove all Y-caps (and the unit will not operate reliably with y-caps). I have inspected units from several other companies and have determined that it was not possible to have ever passed pri-sec test levels without isolating these circuits. What test technique generally accepted by your agency engineers? TIA. R/S, Brian O'Connell Taiyo Yuden (USA), Inc. ------------------------------------------- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
