72)How many times the soft start starting current is the rated current

- Aug 01, 2019-

After using the soft starter, the starting current is 2~3 times of the rated current, which can be estimated by 2.5 times.Operating current, is the rated current of the motor, full load case.Soft starter is only auxiliary to start, reduce the motor starting current, and link the impact on the power grid when the high-power motor starts.

The soft starter USES tri-phase parallel thyristor as voltage regulator, which is connected between the power supply and the stator of the motor.This kind of circuit, such as three-phase fully controlled bridge rectifier circuit, when starting the motor with soft starter, the output voltage of the thyristor gradually increases and the motor gradually accelerates until the thyristor is fully switched on. The motor works on the mechanical characteristic of rated voltage to achieve smooth start, reduce the starting current and avoid starting over-current tripping.When the motor reaches the rated revolution, the starting process ends, and the soft starter automatically replaces the thyristor that has completed the task with bypass contactor to provide the rated voltage for the normal operation of the motor, so as to reduce the thermal loss of the thyristor, extend the service life of the soft starter, improve its working efficiency and avoid harmonic pollution of the power grid.The soft starter also provides soft stopping function. In contrast to the soft starting process, the voltage gradually decreases and the revolution gradually drops to zero to avoid the torque impact caused by free stopping