Electrical Engineering MCQ on Synchronous Motor
Operating speed of synchronous motor can be changed to new fixed value by
Operating speed of synchronous motor can be changed to new fixed value by
- Changing frequency
- Changing the load
- Changing the supply voltage
- Using brakes
Correct answer: 1. Changing frequency
The power factor of a synchronous motor is better as compared to induction motor because
The power factor of a synchronous motor is better as compared to induction motor because
- Mechanical load on the motor can be adjusted
- Stator supply is relieved of responsibility of producing magnetic field
- Synchronous motor has large air gap
- Synchronous motor runs at synchronous speed
Correct answer: 2. Stator supply is relieved of responsibility of producing magnetic field
Maximum power developed in a synchronous motor will depend on
Maximum power developed in a synchronous motor will depend on
- The rotor excitation and supply volt-age both
- The rotor excitation only
- The rotor excitation, supply voltage and maximum value of coupling angle (90°)
- The supply voltage only
Correct answer: 3. The rotor excitation, supply voltage and maximum value of coupling angle (90°)
A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is primarily because
A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is primarily because
- Mechanical load on the rotor remains constant
- Stator supply is not required to produce magnetic field
- Synchronous motor has large air gap
- Synchronous motor has no slip
Correct answer: 2. Stator supply is not required to produce magnetic field
The synchronous motor will always stop when
The synchronous motor will always stop when
- Excitation winding gets disconnected
- Load in motor varies
- Supply voltage fluctuates
- Supply voltage frequency changes
Correct answer: 1. Excitation winding gets disconnected