Soft Starter Accessories

Motors require a great amount of energy when rapidly accelerating to full speed. Variable frequency drives (VFDs) and soft starters can be used to reduce inrush currents and limit torque. This reduces wear and tear caused by frequent starts and stops extending the life of the motor.

Soft starters are solid-state devices that protect electric motors from damage caused by limiting the inrush of current associated with motor startup. They ramp up the initial voltage to the the motor producing a gentle climb to full speed. Soft starters typically use a series of thyristors or silicon controlled rectifiers (SCRs) to reduce the voltage. In the normal “on" state, the SCRs allow current while in the normal “off” state, the SCRs restrict current. The SCRs are engaged during ramp up, and bypass contactors are used after maximum speed is reached. This significantly reduces motor heating.

Soft starters are a cost-effective choice for applications that require torque and speed control during motor startup. Soft starters can be utilized in conveyer belt applications where a gradual startup can prevent misalignment and stress to the belt’s drive components. They can also be used on motors that control pump applications where there is often a risk of power surges.