Question 315Electricity & Electronics - QMED

The correct answer is A) reduced voltage primary resistance starter. This type of starter is used to gradually apply voltage to the motor during the starting process, reducing the initial high inrush current and torque. The primary resistance starter achieves this by inserting a resistor in series with the motor windings during start-up, which limits the voltage and current. Once the motor reaches a certain speed, the resistor is bypassed, allowing the motor to operate at full voltage. The other options are incorrect because: B) across-the-line starter applies full line voltage to the motor, which can cause high inrush current; C) reduced voltage autotransformer starter uses a transformer to step down the voltage during start-up; and D) reduced voltage secondary resistance starter inserts the resistor in the secondary (rotor) circuit, rather than the primary (stator) circuit.