| 摘要 |
PURPOSE:To set the rotating speed of a motor to substantially constant even if a load is applied and to improve the efficiency of the motor by detecting a current, and correcting an output frequency command and an output voltage command in response to the detected value. CONSTITUTION:An essential section is composed of a converter 20, a 3-phase AC power source 21, an inverter 22, a motor 23, a frequency setter 24, a current detector 25, a frequency voltage corrector 26, relay switches 27, 29, amplifiers 28, 30, a voltage instructing circuit 31, an operating state instructing circuit 32, and a frequency voltage controller 33. When a rotating speed and a torque are predetermined values and the motor 23 is driven, a load torque is increased. When the rotating speed is reduced, the corrector 26 operates the controller 33 through the amplifiers 28, 30 to control the output frequency, output voltage of the inverter 23 to suppress an increase in the current. Thus, the rotating speed of a motor can be efficiently controller. |
