Electrical Engineering XYZ MCQs
Rotor resistance speed control is used in:
- Slip ring induction motor
- Synchronous motor
- Squirrel cage induction motor
- DC shunt motor
Correct answer: 1. Slip ring induction motor
Explanation: Slip Ring Induction Motor has a wound rotor connected via slip rings to external resistances. Adjusting the resistance allows control of the motor’s speed. Rotor resistance speed control is specifically used for slip ring induction motors because altering the rotor resistance affects the slip at which the maximum torque occurs. By increasing the rotor resistance, you can increase the slip for a given torque, thereby reducing the speed of the motor. This method provides a means to control speed especially during heavy-load conditions and start-up.