Reducing stray losses

The rotor comprises a plurality of salient poles 14, 16 comprising a main pole body 18, 20 and a pole shoes extending from the body overlying the windings. At least one part of each pole shoe of pole 14 is recessed 40,44 in a circumferential direction with respect to another part of the same pole shoe 42,46, and the recessed part of a pole shoe is aligned with a non-recessed part of an opposing pole shoe 16. This can increase the apparent air gap between adjacent poles, which may allow magnetic flux leakage from one pole to another to be reduced, while still enabling the pole shoe to retain the windings and to distribute magnetic flux across the air gap between the rotor and stator. The laminations may be identically stamped and stacked rotated by 90{ to provide the required recesses. Amortisseur bars (fig 4) may be present and a castellation effect may be achieved (fig 3). Figs 5 and 6 show a coil wedging arrangement.