Assessment of oscillating component of transient moment and selection of network supply switchover time at reactor start of high-voltage asynchronous electric drives

The time of switchover to the network supply is the only controlled parameter at reactor start of powerful asynchronous drives. Switchover to the network supply at the end of the starting mode is accompanied by increasing motor heat losses, while early switchovers are followed by significant impact electromagnetic torques. Justified selection of the switchover time requires a detailed analysis of electromagnetic processes in a motor. The paper demonstrates results of theoretical investigations enabling selection of the switchover time, which can minimize an adverse influence of the oscillating torque component and increased heat generation during start. The authors introduce universal criteria for assessment of motor transient moment oscillation based on the integral parameter - root-mean-square value of the oscillating component of the electromagnetic torque at motor start-up time.