초록 ▼

A permanent magnet motor designed for d-c operation with pulsed current supply through at least two, and preferably four or more stator coils, has a rotor magnetized such that, with respect to 180°-electrical, about 120°are magnetized in one magnetic polarity, and the remaining about 60°are magnetiz

A permanent magnet motor designed for d-c operation with pulsed current supply through at least two, and preferably four or more stator coils, has a rotor magnetized such that, with respect to 180°-electrical, about 120°are magnetized in one magnetic polarity, and the remaining about 60°are magnetized with dual polarity to provide a monopole zone of magnetization and a dipole zone of magnetization, a galvano-magnetic sensing element being exposed to the path of circumferential rotation in which the same polarities of the dipole and monopole zones are contiguous for control of pulse current flow through the windings of the motor. A tacho generator winding may additionally be included in the air gap, exposed only to the rotary path of one magnetic pole of the dipole zone and the monopole zone.

대표청구항 ▼

Brushless d-c motor comprising a stator support; a permanent magnet rotor having first and second essentially annular magnetic regions, wherein the first region defines n poles of alternating polarity, and the second region defines 2n poles of alternating polarity, wherein n is an even number; magne

Brushless d-c motor comprising a stator support; a permanent magnet rotor having first and second essentially annular magnetic regions, wherein the first region defines n poles of alternating polarity, and the second region defines 2n poles of alternating polarity, wherein n is an even number; magnetically-actuable rotor position sensing means (53) supported on the stator support and arranged to be magnetically actuated by the first magnetic region to provide, as a consequence of said actuation, rotor position information, including information relating to the position of one of said magnetic regions of the rotor to the sensing means; stator pole means located on said stator support and positioned for electromagnetic coupling and interaction with the rotor, including two winding means, wherein the stator pole means extends over at least a part of the first and second magnetic regions of the rotor and has an angular extent, in the direction of rotation, over both the first and second regions of approximately two-thirds, or integral multiples thereof, of one pole pitch of the first magnetic region; and controlled switching means, selectively connecting a selected one of said winding means to a source of electrical power in dependence on said rotor position information to provide, in operation, controlled current flow through the selected one of the windings for effecting electromagnetic interaction with the magnetic regions of the rotor.