Abstract: An electrical machine, such as an electric motor, dynamo or alternator has a casing with cooling vents enabling cooling fluid to flow into and out of the casing when the rotor of the electrical machine rotates. The rotor may be formed from conductive elements connected together at their outer regions by inter-connecting members which have vanes arranged to direct cooling fluid over the outer regions. Each conductive element is a metal strip with legs bent in opposite directions relative to the plane of the strip. Portions of the windings of the rotor are spaced apart to allow fluid to flow between the windings to enhance the cooling effect. With a current carrying rotor, varying the axial separation of the rotor and the stator varies the magnetic field intensity across the rotor.

Abstract: An electrical machine, such as an electric motor, dynamo or alternator has a casing with cooling vents enabling cooling fluid to flow into and out of the casing when the rotor of the electrical machine rotates. The rotor may be formed from conductive elements connected together at their outer regions by interconnecting members, which have vanes arranged to direct cooling fluid over the outer regions. Each conductive element is a metal strip with legs bent in opposite directions relative to the plane of the strip. Portions of the windings of the rotor are spaced apart to allow fluid to flow between the windings to enhance the cooling effect. With a current carrying rotor, the magnetic field intensity across the rotor is varied by varying the axial separation of the rotor and the stator.

Abstract: There is disclosed a rotor for an electrical machine, the rotor having a current-carrying winding comprising a plurality of circumferentially distributed winding portions which lie in at least one plane perpendicular to the rotor axis, and extend from a radially inner region to a radially outer region. A commutator is provided by surfaces of the winding portions at the inner region, and the winding is formed from a plurality of conductive sections, each having ends which lie at said outer region, interconnections between the winding sections being made only by way of those ends. Thus, soldered connections made between the winding sections will be remote from the commutator, which is the main source of heat for overheating, and moreover will be at positions where air cooling due to rotor movement is greatest. Air gaps between the winding portions at the outer region aid this cooling affect even further.