Abstract: A stator for an electric machine includes a generally cylindrical stator core having a plurality of circumferentially-spaced and axially-extending core teeth that define a plurality of circumferentially-spaced and axially-extending core slots in a surface thereof, a main winding having a plurality of coils, each of the coils including a plurality of turns occupying the plurality of slots in the stator core, and a tertiary excitation winding having a plurality of coils, each of the coils including a single turn occupying at least a subset of the plurality of slots in the stator core. The coils of the main winding are unevenly arranged in the plurality of slots.

Abstract: A stator for an electric machine includes a generally cylindrical stator core having a plurality of circumferentially-spaced and axially-extending core teeth that define a plurality of circumferentially-spaced and axially-extending core slots in a surface thereof, a main winding having a plurality of coils, each of the coils including a plurality of turns occupying the plurality of slots in the stator core, and a tertiary excitation winding having a plurality of coils, each of the coils including a single turn occupying at least a subset of the plurality of slots in the stator core. The coils of the main winding are unevenly arranged in the plurality of slots.

Abstract: A stator for an electric machine includes a generally cylindrical stator core having a plurality of circumferentially-spaced and axially-extending core teeth that define a plurality of circumferentially-spaced and axially-extending core slots in a surface thereof, a main winding having a plurality of coils, each of the coils including a plurality of turns occupying the plurality of slots in the stator core, and a tertiary excitation winding having a plurality of coils, each of the coils including a single turn occupying at least a subset of the plurality of slots in the stator core. The coils of the main winding are unevenly arranged in the plurality of slots.

Abstract: A stator for an electric machine includes a generally cylindrical stator core having a plurality of circumferentially-spaced and axially-extending core teeth that define a plurality of circumferentially-spaced and axially-extending core slots in a surface thereof, a main winding having a plurality of coils, each of the coils including a plurality of turns occupying the plurality of slots in the stator core, and a tertiary excitation winding having a plurality of coils, each of the coils including a single turn occupying at least a subset of the plurality of slots in the stator core. The coils of the main winding are unevenly arranged in the plurality of slots.

Abstract: An electric machine for a vehicle includes a rotor and a plurality of laminations stacked to form a stator core. Each of the laminations has teeth extending towards the rotor and defining slots. The stator core includes first and second sets of laminations. The teeth of the first set are narrower than the teeth of the second set. The electric machine also includes windings wound in the slots to form coils.

Abstract: A method of insulating a coil of an electrical machine includes applying an insulating varnish to a coil of conductive wire. The varnish includes (i) a resin; (ii) a first catalyst having a first activation temperature, the first catalyst being active at room temperature; and (iii) a second catalyst with a second activation temperature substantially higher than the first activation temperature. The varnish is allowed to partially cure at room temperature. The coil is mounted to a yoke to form a rotor of the electrical machine. The rotor is operated so as to heat the coil and activate the second catalyst to complete curing of the varnish.

Abstract: A method of insulating a coil of an electrical machine includes applying an insulating varnish to a coil of conductive wire. The varnish includes (i) a resin; (ii) a first catalyst having a first activation temperature, the first catalyst being active at room temperature; and (iii) a second catalyst with a second activation temperature substantially higher than the first activation temperature. The varnish is allowed to partially cure at room temperature. The coil is mounted to a yoke to form a rotor of the electrical machine. The rotor is operated so as to heat the coil and activate the second catalyst to complete curing of the varnish.

Abstract: A method of servicing an electro-dynamic apparatus (10) such as a traction motor of a locomotive wherein a degraded surface (52) of electrical insulation (50) in the interior of the apparatus is spray coated with a layer of a sealing material (56). The service is provide without the necessity for removing or disassembling the apparatus by inserting a nozzle (64) of a spraying device (60) through an access opening (42) in the frame head (20) of the apparatus. The sealing material is delivered to the nozzle through a flexible delivery tube (66) having an inner tube (80) defining a passageway (82) for the sealing material and a concentric outer tube (84) defining an annular passageway (86) for compressed air for propelling the sealing material from the nozzle.

Abstract: A method of servicing an electro-dynamic apparatus (10) such as a traction motor of a locomotive wherein a degraded surface (52) of electrical insulation (50) in the interior of the apparatus is spray coated with a layer of a sealing material (56). The service is provide without the necessity for removing or disassembling the apparatus by inserting a nozzle (64) of a spraying device (60) through an access opening (42) in the frame head (20) of the apparatus. The sealing material is delivered to the nozzle through a flexible delivery tube (66) having an inner tube (80) defining a passageway (82) for the sealing material and a concentric outer tube (84) defining an annular passageway (86) for compressed air for propelling the sealing material from the nozzle.