What is the primary function of a starter in a three-phase motor?

The primary function of a starter in a three-phase motor is to provide the necessary starting torque. When a three-phase motor is started, it requires a significant amount of torque to overcome inertia and begin rotation. The starter ensures that the motor receives the appropriate amount of current during startup, allowing it to reach its operational speed efficiently.

Starters may use various techniques, such as reducing the initial voltage or applying resistance, to gradually increase the motor's torque and prevent excessive inrush current. This controlled application of power not only helps achieve the required torque but also protects the motor and electrical system from damage due to high starting currents.

While other options may relate to aspects of motor performance, they do not directly address the fundamental purpose of a starter. For instance, increasing voltage is not a primary function because starters typically manage voltage to achieve smoother starting. Decreasing current is a consequence of controlling the starting conditions rather than the main function, and limiting temperature is more aligned with operational safeguards rather than the starting function. The emphasis on providing necessary starting torque highlights the critical role starters play in the operational success of three-phase motors.