Brian - In using the older standards, the temperature compensation inequalities are slightly different. In 1.4.12 of the 60950 standards, if Tmax is specified,
(T - Tamb) ltet (Tmax - Tmra) or (T) ltet (Tmax - Tmra + Tamb) >From 60950-1, (T) ltet (Tmax + Tamb - Tma). Other than variable naming, it looks the same to me. This ignores the 10ºC differential for using thermocouples. Regards, Peter L. Tarver, PE Product Safety Manager Sanmina-SCI Homologation Services San Jose, CA [email protected] > From: Brian O'Connell > Sent: Monday, June 02, 2003 2:00 PM > > Mr Hughes and Mr Tarver > > > So, assuming I measure a max temperature of less > than 120 deg ( - measurement uncertainty) in my > (Class B) isolation transformers, using embedded > thermocouples, for all rated combinations of > rated air-flow and power outputs, then the xfmrs > pass the heating test. > > But, using UL60950 3d ed and EN60950:2000, for 50 > deg ambient, the max temp is greater. > > Please advise if any errors in my interpretation. thanx. > luck, > > Brian 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: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
