Abstract: A variable-reluctance electric motor with teeth of uniform pitch and poles whose number is a multiple of 4, which includes means for varying the magnetic permeability of the poles in dependance upon the relative positions of the poles and teeth from a zero value to saturation value reached when a tooth faces the middle portion of a pole, passing through intermediate values when a tooth faces the edge portions of a pole. In a first embodiment, the poles are made up of a mixture of magnetic and non-magnetic material, the ratio of magnetic material to non-magnetic material decreasing from the middle portion of the pole to the edge portions. In a second embodiment, the poles are distributed in sectors each containing a central pole and two equal numbers of lateral poles. In a sector, the pitch of the poles is non-uniform, the pitch of the lateral poles being slightly less than the pitch of the teeth.

Abstract: A variable-reluctance electric motor comprises a stator of ferromagnetic material, having poles provided with induction windings and distributed in four equal groups. The motor is provided with at least one ferromagnetic material rotor ring having equidistant teeth and bearing switching means actuated by the rotation for distributing direct current to the stator windings. The windings and switching means are so combined that, during each advance of the rotor by one tooth pitch, each pole is subjected to two opposite switching operations staggered by a time equal to that taken by the motor for a one-fourth of a tooth pitch rotation. The stator poles are equidistant, each bearing one winding, and are number (4kl), k being at least equal to 2 and l being any number. The rotor has (lm) teeth, m being an odd number greater than (4k). The switching means are so actuated as to switch over the d.c.