New press curable Class F ground insulation system for AC machines

To achieve improved efficiency and higher output in both AC motors and generators, an insulation system must be capable of withstanding high volts per mil stress and high operating temperatures. To obtain such performance the development of a new B-staged epoxy resin rich press curable mica paper tape must address several key elements. This paper presents definitions for establishing a Class F resin rich tape system; proposes a new laboratory procedure for producing test specimens; and presents test data on both laboratory specimens and production coils which verify the successful development of a new press curable mica paper tape insulation system for AC motor and generator coils and bar windings.