Westinghouse Electric Corporation

Aeg Westinghouse Transportation Systems

Edward J Croop

Dean C Westervelt

Howard E Saunders

Thomas S Snyder

George D Dixon

Electrical insulation which has good dielectric strength, good radiation resistance, and good thermal resistance at temperatures of up to 500.degree. C. and, preferably up to 1700.degree. C., includes a substrate which is flexible, has the form of a filament, sheet, wrapper, tape or sleeve, and consists essentially of inorganic materials selected from the group consisting of inorganic fibers and metals, metalloids, or alloys; and at least one layer of at least one oxide of an alkoxide-forming element provided on the substrate to impregnate and/or coat same. The insulation is prepared by a process including applying a solution containing an alkoxy gel polymer, optionally additionally containing at least one inorganic material in finely divided form, to the substrate to provide a treated substrate useful as a preform when allowed to set under ambient conditions. The preform is applied to a part by, for example, wrapping, and is heated to pyrolyze the alkoxy gel polymer to its oxide and provide electrical insulation consisting essentially of inorganic materials. The application and pyrolysis steps may be repeated to build up the thickness of the at least one oxide.

Electrical insulation, manufacturing method, and use thereof

A flexible resin adhesive coated substrate is made by: (A) coating a sheet material with a wet, heat reactive adhesive resin, containing a monomer and an amount of an ultraviolet radiation sensitive photoinitiator effective to cause polymerization of monomer in response to ultraviolet radiation, and (B) applying ultraviolet radiation to the adhesive resin coating on the sheet material to polymerize monomer without the application of heat, forming a dry, uncured coating of adhesive bonded to the sheet material.

Method of making heat curable adhesive coated insulation for transformers

A porous, electrical insulating adhesive substrate is made by (A) electrostatically coating a flexible sheet material with heat reactive adhesive resin particles, having an average particle size of between about 1 micron to 2,000 microns, the adhesive particles are applied in a predetermined pattern on the sheet covering from about 10 percent to 90 percent of the sheet material area, the area between the resin pattern not being coated; and then (B) heating the patterned coated sheet material between about 65.degree. C to 250.degree. C, forming a discontinuous, 0.25 mil to 25 mil (0.006 mm to 0.635 mm) thick, dry coating pattern of heat reactive adhesive particles bonded to the sheet material, said heat reactive adhesive coating covering from about 10 percent to 90 percent of the sheet material area; the patterned coated sheet may then be inserted as an oil permeable layer insulation between high voltage windings and low voltage windings and between layers of high and low voltage windings in a wound coil assembly, after which the assembly can be heated at a temperature and for a time effective to securely bond the winding layers together, and thus provide a porous, oil permeable, bonded transformer coil assembly.

Apparatus for making electrical coils using patterned dry resin coated

A porous, electrical insulating adhesive substrate is made by (A) electrostatically coating a flexible sheet material with heat reactive adhesive resin particles, having an average particle size of between about 1 micron to 2,000 microns, the adhesive particles are applied in a predetermined pattern on the sheet covering from about 10 percent to 90 percent of the sheet material area, the area between the resin pattern not being patterned and then (B) heating the patterened coated sheet material between about 65.degree.C to 250.degree.C, forming a discontinuous, 0.25 mil to 25 mil (0.006 mm to 0.635 mm) thick, dry coating pattern of heat reactive adhesive particles bonded to the sheet material, said heat reactive adhesive coating covering from about 10 percent to 90 percent of the sheet material area; the patterned coated sheet may then be inserted as an oil permeable layer insulation between high voltage windings and low voltage windings and between layers of high and low voltage windings in a wound coil assembly, after which the assembly can be heated at a temperature and for a time effective to securely bond the winding layers together, and thus provide a porous, oil permeable, bonded transformer coil assembly.

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Pittsburgh, PA, United States of America

Edward J Croop