| 摘要 |
<p>PURPOSE:To enable to always maintain the prescribed operating conditions irrespective of the variation in the torque of an induction motor by accurately detecting always the torque of the motor during the operation. CONSTITUTION:A multiplier 12 receives an error signal fe from an amplifier 2 and an energizing current control signal IM from an energizing current instructing circuit 3, and outputs the multiplied result. Thus, the rotating speed of an induction motor is controlled, and even if the signal IM varies, a signal T which represents the torque generated by the motor is always accurately obtained at the output of the multiplier 12. When this is indicated by a suitable meter or the like, the actual torque of the motor can be notified during the operation in a machine tool or the like at the real time. Further, the exciting current of the motor is controlled in response to the detected torque, thereby maintaining the operating conditions of the motor preferably.</p> |
