| 摘要 |
PURPOSE:To effectively rotate a synchronous motor in the desired direction by supplying a DC current to an armature coil at the starting time when the motor is driven by an inverter, and gradually accelerating the rotating speed of the motor after the motor is stopped at the prescribed position. CONSTITUTION:A 3-phase synchronous motor used for a VTR or the like is driven by controlling the commutation of an armature coil 1 with an inverter 4. A timing pulse generator 6 of a starter 5 is operated at the starting time to reset a ring counter 9, the prescribed 2-phase transistor of the inverter 4 is conducted to supply a DC current, the output of a lamp voltage generator 7 is applied to a voltage controlled oscillator 8, the inverter 4 is controlled via a counter 9 and an AND gate 10, and the oscillation frequency is gradually increased, thereby accelerating the rotating speed of the motor. Accordingly, the motor can be effectively rotated in the desired direction without the structure of mechanical auxiliary means or the motor. |
