EEE :: Synchronous Motors
- A synchronous motor is running on a load with normal excitation. Now if the load on the motor is increased
- To limit the operating temperature an electrical machine should have proper
- In a synchronous motor, the magnitude of stator back e.m.f. £& depends on
- In a synchronous motor, the magnitude of stator back e.m.f. Eb depends on
- If excitation of a synchronous motor running with a constant load is decreased from its normal value, ignoring effects of armature reaction, it leads to
- If load (or torque) angle of a 4-pole synchronous motor is 6° electrical, its value in mechanical degrees is
- In a synchronous motor running with fixed excitation, when the load is increased three times, its torque angle becomes approximately
- If in a synchronous motor, driving a given mechanical load and drawing current at a leading power factor from constant voltage supply its field excitation is increased, its power factor
- Synchronous motors are generally not self-starting because
- The synchronous motor is not inherently self-starting because
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A.
the force required to accelerate the rotor to the synchronous speed in an instant is absent |
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B.
the starting device to accelerate the rotor to near synchronous speed is absent |
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C.
a rotating magnetic field does not have enough poles |
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D.
the rotating magnetic field is produced by only 50 Hz frequency currents |