Abstract: Series loops of the stator of a large steam turbine-generator are electrically insulated from each other by enclosing each of them in its own clamshell thermoplastic resin mold and filling the mold with an electrically-insulating thermosetting resin material which bonds to the metal of the series loops and the stator bars and bonds also to the ground insulation covering on the stator bars and to the mold and together with the mold provides in cured form an integral body which is resistant to vibrational and impact forces and to distortional forces incident to thermal cycling of the equipement in normal use.

Abstract: A thermosetting resin composition of an epoxy resin mixture of 1,2 epoxy resin having at least two epoxide groups per molecule and a polyglycol diepoxide having viscosity of 2,000-5,000 centipoises at 25.degree. C. and in addition small but effective amounts of both a catalytic hardener and an accelerator has special utility in the production of composite molded bodies of electrical insulation having thermoplastic shells because of its unique combination of properties including thermal stability, thermal-cycling crack resistance, high impact strength, toughness, room-temperature curability and bondability to both thermoplastic and metallic surfaces, and because it does not stress crack thermoplastic shells to which it is bonded in curing.

Abstract: A thermosetting resin composition of an epoxy resin mixture of 1,2 epoxy resin having at least two epoxide groups per molecule and a polyglycol diepoxide having viscosity of 2,000-5,000 centipoises at 25.degree. C. and in addition small but effective amounts of both a catalytic hardener and an accelerator has special utility in the production of composite molded bodies of electrical insulation having thermoplastic shells because of its unique combination of properties including thermal stability, thermal-cycling crack resistance, high impact strength, toughness, room-temperature curability and bondability to both thermoplastic and metallic surfaces, and because it does not stress crack thermoplastic shells to which it is bonded in curing.

Abstract: Series loops of the stator of a large steam turbine-generator are electrically insulated from each other by enclosing each of them in its own clamshell thermoplastic resin mold and filling the mold with an electrically-insulating thermosetting resin material which bonds to the metal of the series loops and the stator bars and bonds also to the ground insulation covering on the stator bars and to the mold and together with the mold provides in cured form an integral body which is resistant to vibrational and impact forces and to distortional forces incident to thermal cycling of the equipment in normal use.

Abstract: A grading layer for a slot armor in an electric machine employs a layer of semi-conducting particles of silicon carbide bonded to the face of insulation of the slot armor. A layer of a tough high temperature paper such as an aramid paper separates the silicon carbide from the windings. The voltage gradient at the radially outerward extremity of the windings is capacitively coupled through the aramid paper to the silicon carbide layer wherein span-wise conduction decreases the peak voltage gradient to reduce the likelihood of the formation of corona and flashover.

Abstract: Electrical insulating sheet material characterized by a coating of thermosetting resinous adhesive material distributed over two sides of a sheet of aramid paper, in combination with a pattern of pressure sensitive adhesive material applied to one side of the aramid paper sheet.

Abstract: Electrical insulating sheet material characterized by a coating of thermosetting resinous adhesive material distributed over two sides of a sheet of aramid paper, in combination with a pattern of pressure sensitive adhesive material applied to one side of the aramid paper sheet. An electrical winding insulated with the sheet material of the invention is characterized by incorporating sheets of the insulating material between facing flat sides of the turns of the winding with the sheets initially held in position on the winding during early phases of its manufacture by the pressure sensitive adhesive. In the final manufactured form of the winding its turns are compressed and baked to thermally cure the thermosetting resinous adhesive material and bond it to the sides of the winding and the aramid paper sheet.

Abstract: Lamination of the stator core is accomplished by stacking the core with a series of segments or punchings of steel each of which is insulated with a layer of adhesive enamel on both sides. The adhesive enamel is comprised of an epoxy resin and a sufficient amount of a glass fiber spacer filler to substantially provide uniform separation and insulation between the individual segments.

Abstract: Composite electrical insulating material is protected by at least one outer polymeric layer which dissolves in the bonding or impregnating resin at elevated temperatures, permitting ready handling of the relatively fragile insulating material, and by reason of dissolution when installed, permitting the ready further impregnation of the assembled insulation.