General Electric Company

William E Tomak

Mark Markovitz

James Jonathan Grant

Jeffrey D Sheaffer

William Paul Dobbins

Resin-impregnated sheet materials, such as fabrics, films, paper and tapes, for forming electrical insulation that exhibits significantly improved voltage endurance performance. The present invention finds particular use as groundwall insulation for high voltage generator stator bars, in which the groundwall insulation is formed by mica tape filled with submicron particles of silicon dioxide, aluminum oxide, titanium dioxide and/or zirconium dioxide, in combination with an unfilled mica tape impregnated with the same or compatible resin binder. The filled tape is preferably in the form of a mica paper having at least one woven fabric on at least one of its surfaces, a resin binder permeating the mica paper and woven fabric so as to bond the woven fabric to the mica paper, and oxide particles dispersed in the woven fabric.

Electrical insulating material and stator bar formed therewith

A high voltage generator armature bar (10) that exhibits improved performance by forming one or more of its conductive components from a conductive material that uses a tin oxide-based composition as a conductive filler. The armature bar (10) is of the type having one or more tiers of conductor strands (12), strand insulation (14), conductive internal grading (20), groundwall insulation (22), conductive slot armoring (24), and preferably a transposition filler (18). The conductive internal grading (20), the conductive slot armoring (24) and/or the transposition filler (18) contain a conductive filler of antimony-doped tin oxide that may constitute the entire conductive filler, or can be present as a shell on the filler particles.

Stable conductive material for high voltage armature bars

Stator bars for dynamoelectric machines are covered with an electrically conductive tape formed of a fabric support sheet carrying an electrically conductive polymeric binder system comprised of carbon particles dispersed in a polymeric matrix. The carbon particles are preferably selected from carbon black and/or graphite, and are present in the polymeric binder system in an amount of at least 5 percent by weight, based on the weight of the binder system. Low tip-up values of less than 0.025% and increased high voltage breakdown strengths of at least 700 VPM are obtained.

Stator bars internally graded with conductive binder tape

High voltage generator stator bar for electrical generators internally graded with a fast drying, electrically conductive, carbon-filled thermoplastic paint composition exhibit improved electrical dissipation factor tip-up values.

Internal grading of generator stator bars with electrically conducting

A bare copper conductor is provided with a tenaciously adhering epoxy resin by heating and curing in situ on the conductor a coating of a solution of cycloaliphatic epoxy resin, a hardener, stannous octoate as a catalyst, and a phenolic accelerator.

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Scotia, NY, United States of America

William E Tomak