Question

Why is starter necessary in DC motor? Explain its working in brief.

Hint:

Starters limit the initial current to protect DC motors from damage due to high starting currents.

Answer 1

Why starter is necessary: A starter is necessary in a DC motor to limit the high starting current. At starting, the rotor is stationary, so the back EMF is zero. Without a starter, the motor would draw very high current, causing damage to the windings and power supply. Working of starter:
The starter is connected in series with the armature winding.
Initially, the starter provides high resistance in the circuit, limiting the starting current.
As the motor gains speed, the back EMF increases and the current decreases.
The starter resistance is gradually reduced (cut out) in steps until it is completely bypassed, allowing full voltage to the armature.
This gradual removal of resistance protects the motor and the supply system from sudden current surges. Common types of starters include the Rheostat Starter and the Three-point Starter.