Abstract: An insulation system for winding of electric rotating machines having thermal resistance of class H or more and excellent adhesiveness between a conductor and an insulating layer and resistance to thermal stress can be produced by wrapping a plurality of layers of an insulating tape or sheet having thermal resistance of class H or more around a winding conductor, impregnating the thus treated winding conductor with a solventless varnish consisting essentially of 1 equivalent of an epoxy compound containing at least two vicinal epoxy groups, more than one equivalent of an organic polyisocyanate, and then heating the inpregnated winding conductor at a temperature above 60.degree. C. for a time sufficient to form and cure a resin containing as recurring units at least two isocyanurate rings directly bonded to one another through the residue of the polyisocyanate and two oxazolidone rings directly bonded to each other through the residue of the polyepoxide in the presence of 0.

Abstract: A method for producing electrically insulated apparatus, which may be used in windings for rotary electric machines, for example, an induction motor, synchronous machines, DC machines or stationary induction apparatus, for example, transformers, and the product produced thereby comprising an electric conductor and an insulating layer formed around the electric conductor, wherein said insulating layer contains a resin having excellent permeability for the gas generated in the layer, e.g., a silicone resin, and a resin having excellent adhesive force in an appropriate blending ratio in order to impart excellent thermal resistance to the electrically insulated apparatus.