Synchronous motors questions with answers
99 multiple-choice questions. Open any question for its answer and explanation.
- In a 3-phase, 4-pole, 50 Hz synchronous motor, the frequency, pole number and load torque all are halved. The motor speed will be
- The maximum value of torque that a synchronous motor can develop without losing its synchronism, is known as
- A synchronous machine with low value of short-circuit ratio has
- The armature current of the synchronous motor has higher values for
- The induced e.m.f. in a synchronous motor working on leading power factor will be
- The maximum torque which a synchronous motor will develop at rest for any angular position of the rotor, at rated stator supply voltage and frequency, is known as
- Power factor of a synchronous motor is unity when
- In a synchronous motor, V-curves represent relation between
- The oscillations in a synchronous motor can be damped out by
- To limit the operating temperature an electrical machine should have proper
- The power developed by a synchronous motor will be maximum when the load angle is
- When a 3-phase synchronous generator is supplying a zero power factor lagging load, the armature field affects the main field in the following way
- In a 3-phase synchronous motor, the negative phase sequence exists when the motor is
- Synchronous motors are generally not self-starting because
- The efficiency of a properly designed synchronous motor will usually fall in range
- A synchronous motor can develop synchronous torque
- The back e.m.f. in the stator of a synchronous motor depends on
- While starting a synchronous motor by induction motor action, field winding is usually
- The rotor copper losses, in a synchronous motor, are met by
- The minimum armature current of the synchronous motor corresponds to operation at
- When the excitation of an unloaded salient pole synchronous motor suddenly gets disconnected
- A synchronous motor develops maximum power when load angle is
- Slip-rings in a synchronous motor carry
- Which of the following methods is used to start a synchronous motor ?
- In a synchronous motor it the back e.m.f. generated in the armature at noload is approximately equal to the applied voltage, then