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Akihiro Nakajima

Itsuki Ban

An apparatus for removing torque ripples comprises a permanent magnet rotor, position sensors, stator armature coils, an operational circuit for effecting an arithmetic operation on detected signals from the position sensors, and a control circuit for driving the stator armature coils. According to another embodiment, an apparatus for removing torque ripples includes a direct-current motor having Y-connected armature coils, a detector for detecting counterelectromotive forces in the direct-current motor, an operational circuit for effecting an arithmetic operation on output signals from the detector, and a transistor for driving the direct-current motor.

Apparatus for removing torque ripples in direct-current motors

A semiconductor electric motor is disclosed which comprises: an outer housing; a cylindrical magnetic core fixedly mounted to the inside of the outer housing; polyphase armature coils mounted upon the magnetic core; a rotative shaft rotatably held by bearings mounted upon the outer housing; a rotor which is fixed to the rotative shaft and which is excited by exciting coils mounted thereon in such a way that the outer surface is polarized south and north at regular intervals and that the produced magnetic field penetrates through the armature coils; a first core made from a magnetic material and centrally provided with a hole which is made stationary relative to the rotative shaft extending through the hole; a second core made from a magnetic material and fixed inside the outer housing; the first and second cores cooperating with secondary and primary coils respectively mounted upon the first and second cores to constitute a rotary transformer; an RF oscillator consisting of a semiconductor circuit and acting to supply RF alternating current to the primary coil; an electric circuit for rectifying the output from the secondary coil and supplying it to the exciting coils; and an electric current supply control circuit for controlling the electric current supplied to the armature coils to produce a torque in one direction.

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Yokohama, Kanagawa, Japan

Akihiro Nakajima