>Date: Mon, 8 Jul 1996 08:55:39 -0700 >From: Rich Nute <[email protected]> >To: [email protected] >Subject: Re: Transformer requirements in IEC950 >Cc: [email protected]
>Jim Eichner asks several questions about transformer insulations. >4. Does our varnish impregnation help us in any way? > No. For the purposes of safety, varnish is not considered an > insulation. This is because (a) its thickness is not controlled, > (b) its coverage is not necessarily 100%, and (c) it is considered > fragile and subject to damage from handling. >Best regards, >Rich >+===========================================================+ >|Richard Nute |Quality Department | >|Hewlett-Packard Company |Product Regulations Group | >|San Diego Division (SDD) |Tel : 619 655 3329 | >|16399 West Bernardo Drive |FAX : 619 655 4979 | >|San Diego, California 92127 |e-mail: [email protected] | >+===========================================================+ It would seem reasonable to consider that the vacuum impregnation reduces the microenvironment surrounding the transformer windings from a pollution degree 2 to a pollution degree 1 when the equipment is located in a pollution degree 2 environment. This can help a little with primary-secondary end turn creepage distance issues. - Mike Rains
