| 摘要 |
PURPOSE:To obtain a sufficient magnetic force which can move a brake-device operating body even in a starting operation and to prevent an inverter device from being excited excessively even in a low-speed operation in the inverter device wherein an operating member is attracted by the magnetic force of a stator and an induction motor which releases the braking of a brake device is controlled. CONSTITUTION:In a starting operation, a DC-voltage application signal is given to a PWM circuit 20 from a DC-voltage-output control circuit 31. An inverter main circuit 19 applies a DC voltage to a stator coil in an induction motor, an operating body is attracted by the magnetic force of a stator, and a brake device is set to a braking-released state. After a prescribed time has elapsed, a switch device 32 is changed over, and a V/F operation circuit 22 gives a control signal to the PWM circuit 20. The inverter main circuit 19 applies an approximately-sinusoidal-wave voltage to an induction motor, and the motor is turned. The approximately-sinusoidal-wave voltage is made high by a boost voltage Vb by means of the V/F operation circuit 22, and it is held in a position in which the operating body has been attracted. |
