Research on Current Zero-Crossing Time of Mining Phase Controlled Contactor Breaking Motor

Using the current zero-crossing breaking control technology can make the phase-controlled contactor break the load current under the condition of micro-electric arc or less electric arc, reduce the contact loss, improve the electrical life and Breaking capacity of the phase-controlled contactor. Through matlab simulation, paper studies the change law of current zero-crossing time interval when phase-controlled contactor breaks three-phase asynchronous motor under different load torque conditions. Under the same voltage and no-load condition, the zero-crossing time interval becomes longer with the increase of motor power. The larger the motor load torque, the longer the zero-crossing time interval. With the increase of motor load torque, the zero-crossing time interval finally tends to a fixed value. Under the condition of 10%-200% rated load torque change, the change range of zero-crossing time interval becomes smaller with the increase of motor power. Finally, the zero-crossing time interval of the motor under different loads is tested by the experimental platform, which is basically consistent with the simulation results.