What is the primary function of a soft starter in electric motors?

The primary function of a soft starter in electric motors is to gradually increase voltage and reduce inrush current. When an electric motor starts, it typically draws a significantly higher current than its running current, referred to as inrush current. This sudden spike can cause mechanical stress and electrical issues, such as voltage dips in the power supply network.

A soft starter addresses this issue by controlling the voltage applied to the motor during startup. It incrementally ramps up the voltage, allowing the motor to start more smoothly and reducing the inrush current. This gradual acceleration minimizes the stress on the motor's components and the connected electrical systems, leading to improved performance and increased longevity of the motor.

While cooling the motor and increasing starting torque are important considerations in motor operation, they are not the primary functions of a soft starter. Overload protection, on the other hand, is typically handled by other protective devices like overload relays rather than through the soft starting mechanism.