SECOND-GENERATION EPOXY-MICA-PAPER INSULATION SYSTEM FOR LARGE TURBINE-GENERATOR STATOR-WINDINGS.

The development of a second-generation thermoset steam turbine-generator insulation system is described. Reiterative optimization and selection of materials, material composites, and processes are reported. The resulting new insulation is characterized with respect to its short and long-term electrical properties, thermal and dimensional stability. High priority was assigned to the mechanical properties of the new insulation system. The new system takes full advantage of the superior characteristics of mica paper: its uniform, excellent electrical and mechanical properties. The new insulation system offers an uncomplicated manufacturing process which is facilitated by the solventless insulating tape. The development of the new epoxy binder resin has given the new insulation system excellent impact toughness, thermal and dimensional stability and high-voltage capability.