Abstract: A permanent magnet rotor core includes a plurality of rotor poles circumferentially-spaced about a central axis and including a first rotor pole and an adjacent second rotor pole that each include an outer wall, and wherein the rotor core includes a rotor diameter. The rotor core also includes a plurality of radial apertures alternately-spaced with the plurality of rotor poles. The rotor core also includes a first protrusion extending from the first rotor pole into a first radial aperture of the plurality of radial apertures positioned between the first rotor pole and the second rotor pole. The rotor core further includes a second protrusion extending from the second rotor pole into the first radial aperture such that a circumferential opening is defined between the first protrusion and the second protrusion. The opening extends a first length of between approximately 0.052% and approximately 0.058% of the rotor diameter.

Abstract: A permanent magnet rotor core includes a plurality of rotor poles circumferentially-spaced about a central axis and including a first rotor pole and an adjacent second rotor pole that each include an outer wall, and wherein the rotor core includes a rotor diameter. The rotor core also includes a plurality of radial apertures alternately-spaced with the plurality of rotor poles. The rotor core also includes a first protrusion extending from the first rotor pole into a first radial aperture of the plurality of radial apertures positioned between the first rotor pole and the second rotor pole. The rotor core further includes a second protrusion extending from the second rotor pole into the first radial aperture such that a circumferential opening is defined between the first protrusion and the second protrusion. The opening extends a first length of between approximately 0.052% and approximately 0.058% of the rotor diameter.

Abstract: A motor is described that includes a motor enclosure, a motor winding assembly, a motor control unit, and a mid shield. The motor enclosure includes a plurality of protrusions into the motor enclosure in a substantially configuration around its perimeter and the motor winding assembly is configured for placement within the motor enclosure. A portion of the motor control unit is configured for placement within the motor enclosure and the mid shield is configured for placement within the motor enclosure between the motor control unit and the motor winding assembly where it engages the protrusions upon insertion into the enclosure.