We have a "certificate of conformity" shipped with each lot of our transformers. This document defines in detail the materials and construction of the transformer. We have been using this method for a few years on about 3-4 transformers and have not had any problems with the UL factory inspections. We have had two UL field inspectors in that time span. I would contact your UL field inspector and propose this idea to him/her. Good Luck
-----Original Message----- From: Chris Wells [mailto:[email protected]] Sent: Wednesday, April 25, 2001 8:42 PM To: 'emc-pstc' Subject: Fw: Transformer Question ----- Original Message ----- From: Wells, Christopher D <[email protected]> To: 'Chris Wells' <[email protected]> Sent: Wednesday, April 25, 2001 9:19 AM Subject: RE: Transformer Question > Tac Pham - Regarding transformer recognition. > When I have designed a custom power supply like Ken has and the transformer > is made by an outside vendor, then I have inspection problems with UL. That > is if I try to keep it simple under just an insulating system. > The problem usually boils down to proving that the transformer is what my > drawings say it is. > The UL file calls out the vendor # and my drawings detail, but he/she wants > me to prove it. > Since I do not manufacture the transformer it doesn't work. > I can't easily show that the varnish is this brand, the tape another, the > bobbin is etc - I get stuck in a mess. > > The only way I know to clearly get out of this issue is to have the > transformer construction controlled in a file by the vendor. > The vendor is then checked for these details which they can prove since they > manufacture it and then my UL inspector leaves me alone and I am happy. > Costs me ~ $2K which is worth the headaches that go away! > > If there is another way to keep me out of the inspection loop that would be > great. > I have found that some mag vendors will not do the work to get a > construction file. > Some how they expect me to do it relative to their process - I do not see > how that can work! > > Anyways it sounds like you have been through this many more times than I. > Any more feed back on the subject would be greatly appreciated. > > Thanks > Chris Wells > Sen. Des. Eng. > Cutler-Hammer > Power Management Products Center > Pittsburgh Pa. > ph 412 490 6862 > FAX 412 490 6803 > > > -----Original Message----- > > From: Chris Wells [SMTP:[email protected]] > > Sent: Wednesday, April 25, 2001 1:44 AM > > To: Wells, Christopher D > > Subject: Fw: Transformer Question > > > > > > ----- Original Message ----- > > From: Pham, Tac <[email protected]> > > To: 'Matsuda, Ken' <[email protected]>; <[email protected]> > > Sent: Monday, April 23, 2001 11:21 AM > > Subject: RE: Transformer Question > > > > > > > > > > Ken, > > > > > > Depend on the type of transformer, such as isolating or signal, you > > should > > > be aware of the following: > > > > > > 1. The temperature rating would dictate the insulation class A (105), B > > > (130), and so on... in accordance with IEC85. These insulating systems > > will > > > identify the tapes, wires, plastic material, varnish. Every time you > > request > > > for the substitution of these component, you must ensure that new > > components > > > are specified in the insulation system. > > > > > > 2. It does not matter that your company or your vendors manufactured > > this > > > transformer, UL will require a copy of winding sheet, a BOM for review, > > that > > > including type of tapes, bobbin material, sleeving... and constructional > > > such as margin, creepage. > > > > > > 3. Your transformer is customized and use in only one power supply > > model, > > it > > > is not required this xfmr bear the UL recognition mark. Many > > manufacturers > > > provides the UL recognition mark on transformers , but the end-users > > must > > > verify the thermal, short circuit test... per specific application. > > > > > > 4. If you have a second source (more than one vendor) for this xfmr, > > then > > > your report must identify all vendors and theirs insulation system. > > > > > > Please note that only UL has this requirement, other agencies determine > > the > > > temperature class by the rating of material without additional tests as > > an > > > insulation system. > > > > > > Tac Pham > > > Power-One TSD > > > 949-261-2200 > > > > > > > > > > > > > > > -----Original Message----- > > > From: Matsuda, Ken [mailto:[email protected]] > > > Sent: Saturday, April 21, 2001 1:38 AM > > > To: [email protected] > > > Subject: Transformer Question > > > > > > > > > > > > Group, > > > > > > I was wondering if you could help me with this one? Currently, I have a > > > switching power supply, using custom transformers. Now I am looking at > > > submitting this product to a agency... > > > > > > Many transformer manufacturers claim they build to UL ...standards, > > > obviously, this is not considered approved, but are there > > > > > > transformer houses that can manufacture transformers that are considered > > > recognized components under a program similar to a sign shop program, > > where > > > customers can request custom wound transformers that are covered under > > the > > > UL recognition ? > > > > > > > > > Thanks for any input, > > > > > > > > > Ken > > > > > > ------------------------------------------- > > > 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," ------------------------------------------- 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,"
