Medium voltage soft starter is a new intelligent motor starter, it is suitable for squirrel-cage asynchronous and synchronous motors. It is a Integrated motor terminal control equipment of starter, display, Protection, datacollection . Users can achieve more complex control functions by using fewer components. The medium-voltage soft starter controls the input voltage through the conduction.Angle between the control items in order tochange the voltage value at he starter end of a motor, that is, control the starting torque and starting current of the motor to realize the motor soft start control. Medium voltage soft starter can accelerate smoothly according to the set starting parameters, thus reducing the electrical and mechanical impact on the power grid, motor and equipment.When the motor reaches the rated speed, the bypass contactor is switched on automatically. The medium voltage soft starter continues to monitor the motor after starting and provides various fault protection.