Correct Answer - Option 2 : Requires DC excitation for the rotor
Concept:
Single phase synchronous motor:
A single phase synchronous motor is also called as reluctance motor.
Construction:
- The stator of the motor has the main and auxiliary winding. The stator of the single phase reluctance and induction motor are same.
- The rotor of a reluctance motor is a squirrel cage with some rotor teeth removed in the certain places to provide the desired number of salient rotor poles.
Working:
- Reluctance motor torque is produced due to the tendency of the rotor to align itself in the minimum reluctance position.
- Speed of the motor is close to the synchronous speed. The rotor pulls in synchronism.
- The load inertia should be within the limits, for proper effectiveness.
- At synchronism, the induction torque disappears, but the rotor remains in synchronism due to synchronous reluctance torque.
Advantages of reluctance motor:
- It doesn’t require DC supply.
- Stable characteristics
- Maintenance is less
- Less heat
- No magnets
- It is self-starting.