Abstract: A 3-phase, pole-changeable, phase-modulated winding providing alternative pole-number working by 6-terminal changeover switching. The winding provides 3-parallel, 3-phase, star-connected winding branches for both the alternative pole-number connections. In a preferred arrangement all the winding parts are energized for both the alternative pole-number connections.

Abstract: A pole-amplitude modulation (P.A.M.) three-phase, pole-number changing machine having star-connected and delta-connected stator winding components, thereby providing additional means for reducing m.m.f. harmonics in the resultant three-phase field. Pole-number changing is effected by reversing the star-connected winding component relatively to the delta-connected component.A design method defines relationships between alternative pole-numbers and stator slot number, and slot-spacing between star- and delta-connected components.

Abstract: Three-phase, alternating current, pole-amplitude modulation (P.A.M.) pole-changing electric motors or generators having series/parallel connection of phase winding parts for the alternate pole-members. To obtain approximately equal air-gap flux-density for both pole-numbers, selected coils are provided in branch connection with the main phase winding parts and switched in circuit for one pole-number only. Such selection, to be consistent with normal coil-reversal requirements of pole-changing by P.A.M., is shown to necessitate branch coils represented by similarly angularly positioned vectors in each phase-winding and of equal number in the reversed and non-reversed phase-winding parts.

Abstract: Alternating-current, brushless, stator-controlled, asynchronous or synchronous-running, induction machines having a rotor with asymmetry in two axes electrically at right-angles, comprising two machine units coupled mechanically and electrically, to avoid the disadvantage of low-frequency currents in the mains supply experienced with single units. The coupled machine units are preferably combined in a single frame, providing right-angle electrical displacement between the two units. In one form, a single rotor is common to both stator elements. Asynchronous running is effected by extracting slip energy. Also synchronous running can be effected by d.c., as well as a.c., energizing of the stator windings. In neither mode of operation are connections to the rotor required.