Patent ID: 8294317

Claim:
A unidirectionally-energized brushless DC motor including an AC voltage output winding, the unidirectionally-energized brushless DC motor comprising: a frame; a disk that is rotatably attached to the frame; a plurality of plate-like permanent magnets that are disposed on the disk at equal intervals around the disk, magnetic poles being formed in a surface and a back side of the permanent magnet; a predetermined number of first magnetic cores that are fixed to the frame according to the plurality of permanent magnets; a first winding that is wound around each of the first magnetic cores, DC power being supplied to the first winding; a predetermined number of second magnetic cores that are fixed to the frame; and a second winding that is wound around the second magnetic core and connected to a power consumption device, wherein the permanent magnet is located such that an angle formed by a straight line passing through a center of the disk and a center of the permanent magnet and a normal line in a center of a magnetic pole plane of the permanent magnet ranges from 0° to 60°, whereby, when constant DC current is continuously supplied to the first winding, a large-value narrow-angle torque in which a rotation angle range where the disk is rotated in a reverse direction is narrowed while a torque value is large and a small-value wide-angle torque in which a rotation angle range where the disk is rotated in a normal direction is spread while the torque value is small are generated in a characteristic curve of a rotation angle of the permanent magnet and an electromagnetic torque, the rotation angle of the permanent magnet being measured with respect to the permanent magnet in a stable equilibrium operating state based on the first magnetic core, a detent torque becoming zero in the stable equilibrium operating state, the detent torque being generated by an attractive force between the first magnetic core and the permanent magnet during non-power feeding to the first winding, the electromagnetic torque being generated by current of the first winding and the permanent magnet, and the power feeding is performed to the first winding only when the large-value narrow-angle torque is generated, or only when the small-value wide-angle torque is generated.