The VFD has achieved remarkable power-saving effect when used in the drive control of fans and pumps. It is an ideal speed control method. It not only improves the equipment efficiency, but also meets the production process requirements, and greatly reduces the equipment maintenance and repair costs, and also reduces the shutdown period.

In the process of starting the motor, the soft starter gradually changes the conduction angle of the thyristor, so that the starting current of the motor rises smoothly from zero to the maximum value. The whole process runs smoothly, the reliability of the motor power supply is high, the impact torque on the mechanical load is reduced, the impact on the motor itself is small, and the service life of the motor and the entire equipment is prolonged.