Abstract: A variable reluctance electric motor comprises a stator including at least three pairs of pole pieces with windings surrounding at least one of the pole pieces of each pair, and a rotor structure. The rotor structure defines a pair of opposed pole pieces each having circumferentially extending extensions on the opposite sides thereof. The extensions extend at least to the adjacent pair of stator pole pieces when the rotor pole pieces are aligned with stator pole pieces, and be selective energisation of the pairs of stator pole pieces, the rotor can be made to move angularly in either direction.

Abstract: A rotary actuator comprises a stator structure defining a magnetisable pole piece and an angularly movable rotor structure which defines a pole element. The pole piece and pole element form part of a magnetic circuit and a winding is provided about a portion of the magnetic circuit defined by the rotor and stator structures. The faces of the pole piece or pole element which are presented to each other are provided with a slot or a cutaway portion which extends along at least part of the circumferential length of the face whereby a desired torque/angle characteristic is obtained.