Abstract: A pole-amplitude modulation type, speed-changing, 3-phase alternating current electric motor or generator having a composite stator winding comprising two 3-phase winding components. The 3-phase winding components are in themselves pole-amplitude modulation pole-changing, 3-phase windings, but may possess unsuitable electrical characteristics for practical use. The two components are combined the first component being wound on the first half of the stator and the second component being wound on the second half of the stator whereby the composite stator winding is given acceptable electrical characteristics, particularly in respect of harmonic content, or sub-harmonic content, of MMF waveform.

Abstract: A two-speed, single-phase a.c., shaded-pole, induction motor with pole-changing, in ratio other than 2:1, by pole-amplitude modulation. The motor has stator and squirrel-cage rotor elements. The stator is made with an even number of salient poles, arranged as an even number of pole-groups, wound with at least one less number of coils than poles. Pole-changing is by reversal of the coils of consecutive pole-groups.

Abstract: A 3-phase, alternating current electric motor or generator having a stator winding comprising three phase-windings in start-connection wound on a stator having a slot-number not divisible by "3", yet providing a substantially balanced 3-phase winding. The stator winding coils are disposed to provide a high positive-sequence distribution factor and a low negative-sequence distribution factor. This is achieved with two of the phase-windings having an equal number of coils to each other, the third phase-winding having a different number.