| 摘要 |
PURPOSE:To smoothly switch a power at the time of starting a voltage type inverter by utilizing the output control and the output voltage feedback signal of a voltage control circuit. CONSTITUTION:A commercial power 1 is connected to a motor 6 to start the motor, and after the start, a conductor 8 is opened, the conductor is then closed after the remaining voltage of the motor is attenuated, and the motor is transferred to an inverter operation. The inverter operation is achieved by setting the frequency for the inverter 3 to a frequency lower than that corresponding to a voltage control circuit 18, stopping the operation of the circuit 18, and supplying electric power from the inverter 3 to the motor before the motor speed is reduced to the speed corresponding to the output of a setter 9. Then, after the inverter frequency is increased to the value corresponding to the motor speed, the operations of a V/F converter 10 and the circuit 18 are started to drive the motor at the speed determined by the output of the setter. |
