When the test gets done is something that the end-use standard needs to spell out. As Mike points out it can be very critical. For transformers with nylon bobbins a few seconds delay can change the results, and some standards insist on immediate testing. As someone else pointed out, other standards say to do it once the unit has cooled back down. In my opinion this is too lenient, and I would feel free to not wait, based on the argument that the test is tougher the sooner you do it.
Regards, Jim Eichner > Group Leader - Engineering Services > Xantrex Technologies Corporation [email protected] > phone: (604) 422-2546 > fax: (604) 420-1591 Any opinions expressed are those of my invisible friend, who really exists. Honest. > -----Original Message----- > From: Rains,Mike [SMTP:[email protected]] > Sent: Friday, December 17, 1999 5:01 AM > To: '[email protected]' > Subject: RE: Electric Strength After Abnormals > > > I haven't done a transformer abnormal/overload test in years but it used > to > be common to have a hipot failure if done immediately after the load was > removed (first few seconds) while the transformer passed after cooling > down > for a few minutes. CSA and UL always required that the test be done > successfully immediately after the load was removed. > > Mike Rains > Foxboro Co. > > -----Original Message----- > From: [email protected] <mailto:[email protected]> > [SMTP:[email protected]] <mailto:[SMTP:[email protected]]> > Sent: Thursday, December 16, 1999 10:45 AM > To: [email protected] <mailto:[email protected]> > Subject: Electric Strength After Abnormals > > > Dear All, > > After an Abnormal Test for UL1950/EN60950, should the Electric Strength be > done a) immediately after the Abnormal Test or b) after Abnormal Tesrt > when > unit has cooled down to room temperature c) after Abnormal Test when unit > has cooled down to Normal Heating Temperature Levels. > The standards are not clear! > > +++++++++++++++++++++++++++++++++++ > RTTE Directive Seminar > Renaissance Hotel, Tel-Aviv > 12th January 2000. For details: > http://www.itl.co.il/RTTE.htm <http://www.itl.co.il/RTTE.htm> > +++++++++++++++++++++++++++++++++++ > > > Peter Merguerian > Managing Director > Product Testing Division > I.T.L. (Product Testing) Ltd. > Hacharoshet 26, POB 211 > Or Yehuda 60251, Israel > > Tel: 972-3-5339022 Fax: 972-3-5339019 > e-mail: [email protected] <mailto:[email protected]> > website: http://www.itl.co.il <http://www.itl.co.il> > > > > > > > --------- > This message is coming from the emc-pstc discussion list. To cancel your > subscription, send mail to [email protected] <mailto:[email protected]> > with the single line: "unsubscribe emc-pstc" (without the quotes). For > help, send mail to [email protected] <mailto:[email protected]> , > [email protected] <mailto:[email protected]> , [email protected] > <mailto:[email protected]> , or [email protected] > <mailto:[email protected]> (the list administrators). > > > --------- > This message is coming from the emc-pstc discussion list. > To cancel your subscription, send mail to [email protected] > with the single line: "unsubscribe emc-pstc" (without the > quotes). For help, send mail to [email protected], > [email protected], [email protected], or > [email protected] (the list administrators). > --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
