Abstract: A dynamoelectric machine commutator structure having a plurality of conductive commutator segments secured in operating position by a commutator banding is characterized by including a flexible, thermally stable dielectric coating material between the outer edges of the commutator banding and the conductor segments in order to effectively seal the junction between those members, thereby preventing the deposit or buildup of electrically conductive contaminants at that junction so that the likelihood of electrically short circuiting the conductive segments of the commutator is effectively eliminated. According to the preferred method of the invention, a banded commutator is formed by applying such a coating to predetermined portions of the banding grooves so that the coating effectively seals the junctions between the banding and the conductive segments of the commutator, thereby preventing the accumulation of conductive contaminants at those junctions.

Abstract: A winding form made of readily removable material for use in positioning electric windings in predetermined spaced relationship on an electrical apparatus. A method for mounting a winding on an electrical apparatus using the winding form of the invention is also disclosed wherein the form is mounted in a preselected position on the apparatus, windings are wound around the form, then the form is removed from between the apparatus and the windings by either dissolving it in a suitable solvent or by melting it effectively to dissolve it.

Abstract: A dynamoelectric machine pole and coil assembly having a magnetic pole member around which a preformed coil of insulated magnet wire is mounted. The assembly is characterized by including a plurality of preformed, extended corner sheets of insulating material that are positioned to extend around and beyond each of the corners of the magnetic pole member into overlapping relationship with adjacent extended corner sheets. The extended corner sheets are bonded to the pole member and to one another at their overlapped ends. Projecting tip portions on the magnetic pole member have their upper surfaces completely shielded from the energizing coil by lip parts of the extended corner insulating sheets. A felt piece impregnated with thermosetting resin is used to make a readily conformable corner section of the lip part.

Abstract: A dynamoelectric machine commutator structure having a plurality of conductive commutator segments secured in operating position by a commutator banding is characterized by including a flexible, thermally stable dielectric coating material between the outer edges of the commutator banding and the conductor segments in order to effectively seal the junction between those members, thereby preventing the deposit or buildup of electrically conductive contaminants at that junction so that the likelihood of electrically short circuiting the conductive segments of the commutator is effectively eliminated. According to the preferred method of the invention, a banded commutator is formed by applying such a coating to predetermined portions of the banding grooves so that the coating effectively seals the junctions between the banding and the conductive segments of the commutator, thereby preventing the accumulation of conductive contaminants at those junctions.

Abstract: A dynamoelectric machine pole and coil assembly having a magnetic pole member around which a preformed coil of insulated magnet wire is mounted. The assembly is characterized by including a plurality of preformed, extended corner sheets of insulating material that are positioned to extend around and beyond each of the corners of the magnetic pole member into overlapping relationship with adjacent extended corner sheets. The extended corner sheets are bonded to the pole member and to one another at their overlapped ends. Projecting tip portions on the magnetic pole member have their upper surfaces completely shielded from the energizing coil by lip parts of the extended corner insulating sheets. A felt piece impregnated with thermosetting resin is used to make a readily conformable corner section of the lip part. The cured piece is free of voids, so reinforces the insulation of the ground barrier of the assembly at the critical corner areas.