US Patent 7825552 Cooling arrangement for a variable reluctance electric machine

A variable reluctance electric machine comprising a rotor and a stator; the stator having two or more electromagnetic windings and the rotor having a plurality of salient poles, the salient poles defining axially extending cooling fluid channels; wherein the salient poles and the cooling fluid channels are circumferentially skewed along at least a part of their length whereby in use the cooling fluid channels impel cooling fluid in a substantially axial direction towards the electromagnetic windings and the stator to facilitate heat transfer and dissipation from the windings.