| 摘要 |
An alternating current motor having main and auxiliary windings is provided with a control circuit by which circuit flows in the windings produce a rotating magnetic field for driving the motor so long as control signals applied to the circuit are above a predetermined value and the speed of rotation of the motor is made dependent on the magnitude of the control signals. When the control signals fall below the predetermined value, the current flows in the windings are altered by the control circuit to provide a retarding magnetic field, which may rotate in opposition to the rotating magnetic field for normal driving of the motor, whereby to exert a braking action.
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