What is the main feature of a primary resistance starter?

A primary resistance starter is designed primarily to control the start-up process of an induction motor. When a motor is started directly across the line, it can draw a very high inrush current, which can be several times larger than the motor's full-load current. This high current can lead to problems such as voltage dips in the supply line and mechanical stress on the motor components.

The main feature of a primary resistance starter is that it introduces resistance into the circuit when starting the motor. This resistance effectively reduces the voltage that is applied to the motor at startup. By lowering the voltage, the starter also limits the initial current drawn by the motor. This controlled start allows for a smoother acceleration of the motor, reducing mechanical stress and enhancing the overall longevity of the electrical equipment involved.

This method of applying resistance thus not only protects the motor but also helps to manage the supply network's performance during the starting phase. Starting with reduced voltage prevents excessive torque generation, which can lead to wear and tear or even damage to the motor and connected machinery. The introduction of resistance is removed after the motor has started and reached a certain speed, allowing the motor to operate at the full voltage for efficient performance.

In this context, the other options do not accurately represent the main feature