Abstract: Novel one part, heat cured pressure-sensitive adhesives capable of bonding metallic and non-metallic materials at ambient temperatures and curing at elevated temperatures to form a bond with very high adhesive bond strengths at temperatures up to at least 160° C. The invention is particularly well suited for use with insulated copper coils in electrical generators and includes both the adhesive compositions per se and adhesive transfer tapes capable of bonding to the copper coils at ambient temperatures upon contact due to the pressure sensitive tack of the adhesive. The transfer tapes can subsequently be cured to a hard, thermoset adhesive with high adhesive bond strength. In applications on insulated copper coils, exemplary one part, heat cured pressure-sensitive adhesives can be used either alone or in combination with a substrate to form single or double-sided adhesive tape capable of securing the generator rotor turn insulation.

Abstract: Resin composition comprising an epoxy resin having an epoxide functionality of at least 2.5, a cycloaliphatic epoxy resin, a phenol-formaldehyde novolac and aluminum acetylacetonate. The resin is heat stable and is suitable for fabrication of resin-rich mica tapes having low reactivity at ambient temperatures for good shelf life stability combined with high reactivity above 140° C. for application in press-cured tapes. The dissipation factors at room temperature to at least 200° C. are less than 3.0%.

Abstract: Novel one part, heat cured pressure-sensitive adhesives capable of bonding metallic and non-metallic materials at ambient temperatures and curing at elevated temperatures to form a bond with very high adhesive bond strengths at temperatures up to at least 160° C. The invention is particularly well suited for use with insulated copper coils in electrical generators and includes both the adhesive compositions per se and adhesive transfer tapes capable of bonding to the copper coils at ambient temperatures upon contact due to the pressure sensitive tack of the adhesive. The transfer tapes can subsequently be cured to a hard, thermoset adhesive with high adhesive bond strength. In applications on insulated copper coils, exemplary one part, heat cured pressure-sensitive adhesives can be used either alone or in combination with a substrate to form single or double-sided adhesive tape capable of securing the generator rotor turn insulation.

Abstract: A method for repairing insulation material applied to at least one electrical winding, wherein the method includes identifying an area to be repaired, applying epoxy to the area to be repaired, covering the epoxy with at least one of an adhesive tape and a release film, curing the epoxy, removing at least one of the adhesive tape and the release film, and finalizing the epoxy height.

Abstract: A method for making a dynamoelectric machine conductor bar, compromises providing a plurality of bundled together spiraling strand conductors having surrounding insulation to define a substantially rectangular shape with the strand conductors and strand insulation defining an opposing conductor bar end portion having an electrically insulated gap between the strand insulation adjacent the bar end portion; and applying a filler material to fill the gap to electrically shield the conductor bar end portion and to a greater than 0.080 to about 1.5 inch continuous outer radius surface end portion.

Abstract: Resin composition comprising an epoxy resin having an epoxide functionality of at least 2.5, a cycloaliphatic epoxy resin, a phenol-formaldehyde novolac and aluminum acetylacetonate. The resin is heat stable and is suitable for fabrication of resin-rich mica tapes having low reactivity at ambient temperatures for good shelf life stability combined with high reactivity above 140° C. for application in press-cured tapes. The dissipation factors at room temperature to at least 200° C. are less than 3.0%.

Abstract: A method for making a dynamoelectric machine conductor bar, compromises providing a plurality of bundled together spiraling strand conductors having surrounding insulation to define a substantially rectangular shape with the strand conductors and strand insulation defining an opposing conductor bar end portion having an electrically insulated gap between the strand insulation adjacent the bar end portion; and applying a filler material to fill the gap to electrically shield the conductor bar end portion and to a greater than 0.080 to about 1.5 inch continuous outer radius surface end portion.

Abstract: A method for making a dynamoelectric machine conductor bar, compromises providing a plurality of bundled together spiraling strand conductors having surrounding insulation to define a substantially rectangular shape with the strand conductors and strand insulation defining an opposing conductor bar end portion having an electrically insulated gap between the strand insulation adjacent the bar end portion; and applying a filler material to fill the gap to electrically shield the conductor bar end portion and to a greater than 0.080 to about 1.5 inch continuous outer radius surface end portion.

Abstract: A method for making a dynamoelectric machine conductor bar, compromises providing a plurality of bundled together spiraling strand conductors having surrounding insulation to define a substantially rectangular shape with the strand conductors and strand insulation defining an opposing conductor bar end portion having an electrically insulated gap between the strand insulation adjacent the bar end portion; and applying a filler material to fill the gap to electrically shield the conductor bar end portion and to a greater than 0.080 to about 1.5 inch continuous outer radius surface end portion.

Abstract: 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.

Abstract: An end winding (10) of a high voltage air-cooled ac generator or motor is made more resistant to surface deterioration by corona activity by using a paint whose binder contains at least 20% by weight silicone. An end winding, including its insulated conductors and separator and support structures, are coated with the paint whose composition includes a solvent or thinner, optional pigments, and the binder containing at least 20% by weight silicone. The balance (if any) of the binder can be, for example, an alkyd, acrylic, phenolic or epoxy resin.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A resin composition is provided that is suitable for impregnating sheet material, including fabrics, films, paper and tapes of the type employed to form prepregs, such as tapes used to form electrical insulation layers on electrical components. The resin composition includes a solid or semi-solid epoxy resin having an epoxide functionality of at least 2.5, a metal acetylacetonate for catalyzing the epoxy resin, and an accelerator of bisphenol A-formaldehyde novolac catalyzed by an acidic catalyst and having a hydroxyl equivalent weight of 120. The resin composition is essentially unreactive at room temperature and at elevated temperatures sufficient to enable permeation of the sheet material by the resin in its manufacture, is essentially unreactive at temperatures required to remove moisture and volatiles during processing of articles wrapped or taped with the sheet material, and cures at a higher temperature without adversely affecting the cure characteristics of the resin composition.

Abstract: The method includes sealing the stator bar end connections from within the stator bar end fitting. Particularly, a low viscosity epoxy is initially applied from within the chamber of the end fitting by use of a boroscope and a syringe-type applicator, the low viscosity epoxy being applied to all joints between the adjacent strands of the stator bar and between the fitting and the outermost strands of the stator bar. A high viscosity epoxy is then applied over the low viscosity epoxy using the boroscope and applicator to provide a thick barrier seal between the liquid coolant in the chamber and the brazing material. The epoxy is then cured. The process ensures that the brazing material is isolated from the liquid coolant by the barrier seal whereby potential leaks are prevented and partially developed leaks or leaks extant are arrested because sealant material is disposed at the liquid coolant/braze interface.

Abstract: Low viscosity, solventless, thermosetting resin compositions of bismaleimide resin composition and epoxy resins have unique heat stability and special utility as insulation for electric conductors to be used in the 200.degree.-250.degree. C. temperature range.

Abstract: 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.

Abstract: Low viscosity, solventless, thermosetting resin compositions of bismaleimide resin composition and epoxy resins have unique heat stability and special utility as insulation for electric conductors to be used in the 200.degree.-250.degree. C. temperature range.

Abstract: Curable compositions containing a reaction product of at least one bisphenol polyglycidyl ether, at least one epoxidized novolak and at least one brominated bisphenol, in combination with a polyphenylene ether and further components including specific catalysts and hardeners, may be used in the preparation of laminates useful as printed circuit boards and having excellent physical and electrical properties.