Abstract: An electric machine having a rotor, stator and housing. The rotor includes a radially mounted array of permanent magnets and the stator includes a plurality of electromagnets radially positioned around the rotor. The machine includes a fluid circuit consisting of first and second cavities enclosed by the stator and positioned between the rotor and housing. The fluid circuit also includes an air gap between the stator and rotor and a plurality of ventilation channels extending through the rotor. The air gap and ventilation channels are in fluid communication with the first and second cavities. The rotor also includes an internal fan extending into the first or second cavity. When the rotor is caused to rotate with respect to the stator, the fan causes air or another fluid to circulate through the fluid circuit to cool the rotor.

Abstract: An electric machine having a rotor, stator and housing. The rotor includes a radially mounted array of permanent magnets and the stator includes a plurality of electromagnets radially positioned around the rotor. The stator is encapsulated such that the stator encapsulant is in thermal contact with housing structures, for example the housing end plates. In some embodiments, the entire perimeter portion of the housing is in thermal contact with the stator or the stator encapsulant. The stator encapsulant provides for device robustness and thermal transfer from the stator to the housing. The thermal conductivity of the encapsulant may be enhanced by mixing an additive to the encapsulant to increase thermal conductivity.