Performance analysis of fast reclosing transients in induction motors

Induction motors are used extensively in heavy industry. For these loads, this often requires reclosing on the motor before it reaches zero speed. However, if the supply voltage is applied before the motor reaches zero speed, the motor can be damaged due to excessive current and torque transients. This paper presents a performance analysis of fast reclosing transients in induction motors. It is shown that the optimum time instant for reclosing depends upon the supply voltage and load parameters. The results indicate that the maximum absolute value of instantaneous torque occurs in the first cycle and for every time cycle of supply voltage. In fact, there are at least one positive peak and one negative peak for the torque.