| 摘要 |
PURPOSE:To perform constant-torque control by providing a means to sense the terminal voltage of an induction motor, means of sensing the voltage drop due to a primary impedance, and a means to subtract this voltage drop, and by using the output as a feed back voltage signal. CONSTITUTION:A primary resistance of an induction motor IM, a resistance R1 which corresponds to the first leakage reactance and a reactance X1 are connected to the output of a current transformer CT which senses the first current of the induction motor IM, and the voltage drop due to the primary impedance of the induction motor IM is supplied to the first winding W1 of a transformer Tr. The terminal voltage of the induction motor IM is supplied to the second winding W2 of the transformer Tr, and the difference between the signal supplied to the first winding W1 and the signal supplied to the second winding W2 is output from the third winding W3 as a feed back voltage signal. |
