Development of an impregnating resin having improved VPI properties

The impregnating resin is one of the key factors for producing form wound coils by vacuum pressure impregnation (VPI). The VPI resin influences not only the final properties of the insulation but has also an important effect on production costs. Insulating materials suppliers are searching to improve the impregnants in order to approach to the ideal VPI system with regard to essential properties and requirements. This paper describes the procedure of a development of an impregnating resin considering also the second component of an insulation system the mica paper tapes in order to obtain a VPI system with improved properties.