Insulating coil windings with polyurethane tapes followed - by impregnation with epoxide resins

摘要

Insulating windings by means of insulating tapes for the coils of electrical machines which are impregnated with epoxide resins, by using a polyurethane or products of polyaddition leading to a polyurethane to form the insulating tapes. The impregnating resin is a polyepoxide based on bisphenol A and without free hydroxyl groups, crystalline at ambient temperatures and having an epoxy equivalent of about 175 and the hardener a dicarboxylic acid anhydride of low viscosity optionally in the presence of reactive diluents.