A permanent magnet electric motor includes a shaft extending along a longitudinal axis and a rotor mounted on the shaft. The rotor is rotatable concomitantly with the shaft about the longitudinal axis, the rotor defines an innermost rotor edge. The innermost rotor edge is sized to receive the shaft. The permanent magnet electric motor further includes a stator. The shaft defines a jacket configured to receive a coolant. The jacket is disposed about the longitudinal axis. The jacket is elongated in a first direction. The first direction is parallel to the longitudinal axis. The rotor defines a plurality of longitudinal channels. Each of the plurality of longitudinal channel is elongated along the first direction, and each of the plurality of longitudinal channels is in fluid communication with the jacket to allow fluid flow between the jacket and the plurality of the longitudinal channels.