Electric windings and production thereof.

摘要

Electric windings comprise an electric conductor (1) and a plurality of layers of a cured composite insulating material (2) wrapped around the conductor. The insulating material is obtained by bonding two or more insulating material e.g. glass cloth and mica sheet with a binder solution. After wrapping the insulating material is impregnated with a varnish of an epoxy isocyanate resin, which is then cured. In order that the winding shall have good water resistance in addition to good thermal resistance, and mechanical properties, the binder comprises a mixture of (A) a condensation polymerization type silicone resin having hydroxyl groups and (B) an addition polymerization type silicone resin. The resin (A) preferably is 50 to 95% by weight of the binder and preferably has a hydroxyl group content of 0.2 to 1% by weight.