Abstract: Drive system for a variable reluctance motor having a pulsated drive. The motor has a stator provided with one or more windings for one or more phases, and a rotor which, upon rotation, co-acts with the magnetic circuit in each stator phase and produces in the magnetic circuit for each stator winding a permeance which changes with changes in the rotor angle. A sensing and control circuit (1-10) senses the inductance in the phase winding (L1, L2, L3) in each phase, at least during a part of a rotor revolution. Upon the indication of a pre-determined inductance L.sub.k, the circuit permits the rotational position of the rotor at which the determined inductance L.sub.k was indicated to constitute a starting point for determining a rotational position .theta..sub.OFF) for changing the energized state of the phase winding.

Abstract: Energizing system for a reluctance motor having at least two phases. A sensing and control circuit (1-5) which is constructed to indicate the inductance, or a clearly related magnitude, in the winding in the phase which is next to be energized or activated. The circuit is also constructed to detect the current in the winding in the energized phase and to correct the indicated value of the inductance, or related magnitude, with an operating parameter which has a dependency on the current value in the winding of the energized phase, and to compare this corrected value with a reference value and to utilize the rotational position of the motor rotor, when the corrected value coincides with the reference value, as a starting point for determining a rotational position for changing the energizing state of the phase winding.

Abstract: The invention relates to a method for controlling brushless d.c. motors and to a system for controlling such motors, by varying the effective value of current pulses to the phase windings. According to the invention, upon detection of a maximum current state, the effective value of the pulses is decreased by shortening pulses from a given time point within the normally remaining part of the pulses, irrespective of whether the maximum current state ceases during the time that this part of the pulses should have occurred or not. This time point may coincide substantially with the time point at which the state of maximum current was detected or may coincide substantially with the later time point at which the duration of respective pulses exceeds a predetermined minimum value. The next pulse is introduced at the same time point at which it should normally have been introduced.

Abstract: A variable reluctance motor fed by D.C. pulses is controlled by a rotation sensor. The motor has at least two phases. The stator is designed as a continuous magnetic circuit with two stator poles per phase. The stator poles for the different phases are arranged in sequence along the periphery of the rotor so that each pole adjoins poles pertaining to another phase, and such that diametrically opposed poles pertain to the same phase, each stator pole having at least two teeth per stator pole. The rotor is provided with teeth that cooperate with the stator teeth. The spaces between adjacent stator poles are shorter than the spaces between the teeth of any one stator pole.