Abstract: A reluctance-type motor include a stator having a plurality of salient stator-poles, a rotor having a plurality of salient rotor-poles, a multi-phase coils mounted in the stator, and a driver circuit for driving said multi-phase coil. The driver circuit starts to supply drive current to the multi-phase coils when the salient rotor-poles and the salient stator-poles come across each other. In other words, the drive current is supplied to the multi-phase coils when the inductance thereof is zero.

Abstract: A reluctance-type motor comprises, for each of its rotor and stator, a core that has a cylindrical ring and a plurality of salient poles protruding from the ring in a radial direction of the ring. Each pole has a bottom width and a top width in a circumferential direction of the core at its bottom and at its top, respectively. The bottom width is sized to be larger than the top width, and the ring has a width sized to be larger than a half of the top width of the pole. The pole may be shaped to have a round corner at the bottom or in a trapezoid in which the bottom width is larger than the top width. The core may have a plurality of thin magnetic plates stacked in an axial direction of the core, each plate has a plurality slits in each protrusion which forms the pole, and each plate has a thickness which is less than 5 times of a maximum width of each slit.

Abstract: In a q phase-reluctance type motor including a rotor having 2n rotor protrusions with an arc angle X°, a stator having 2m stator protrusions with an arc angle Y° and m pairs of exciting coils, each of the pairs of exciting coils is disposed around one of the stator protrusions spaced apart at 180° in mechanical angle, and the following conditions are met: q≧5, X°, Y°>360°/(n×q), X°+Y°=180°/n−&agr;°, where &agr;° is a counter torque marginal angle which is larger than 0°.

Abstract: A reluctance type motor apparatus comprises switching devices for energizing phase coils of a motor, diodes for circulating discharge currents of the phase coils, a current sensor for detecting a sum of currents flowing in the phase coils, and a control circuit for controlling energization of the phase coils so that the detected sum of the currents equal a predetermined reference current. The current sensor is positioned between the phase coils and junctions between the phase coils and the diodes. Phase currents supplied to energize the phase coils are varied in dependence on the rotational position of the rotor so that the output torque of the motor does not include ripple.

Abstract: A motor mounting structure is disclosed, by which a central axial line of output shaft can be maintained at the optimum axial position when the motor is mounted on an external device without finishing the motor with high precision. Motor is mounted on actuator by inserting output shaft of motor in insert hole of actuator and fitting the exposed part of radial bearing in engaging recess. In addition, since the engaging surface of engaging recess is finished with high precision relative to radial bearing which have already been finished with high precision, the axial line position of output shaft of motor is brought to the optimum axial line position when motor is mounted on actuator. Therefore, motor can be positioned and connected without finishing the external peripheral surface of body case with high precision.