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

Purpose of a Starter: A starter is essential for DC motors to manage the high current drawn during startup. Since the rotor is stationary at initiation, there is no back EMF. Omitting a starter would lead to excessive current draw, potentially damaging the motor's windings and the power supply. Starter Operation:

• The starter is integrated in series with the armature winding.
• Initially, the starter introduces significant resistance into the circuit, thereby curbing the starting current.
• As the motor accelerates, the back EMF escalates, causing a reduction in current.
• The starter's resistance is progressively decreased in stages until it is entirely bypassed, permitting full voltage to reach the armature.
• This incremental reduction of resistance safeguards the motor and the electrical system from abrupt current surges.

Typical starter configurations include the Rheostat Starter and the Three-point Starter.