Synchronous motors

33. A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will

remain same
go down
improve
none of the above

Detailed SolutionA synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will

38. As the load is applied to a synchronous motor, the motor takes more armature current because

The increased load has to take more current
The rotor by shifting its phase backward causes motor to take more current
The back e.m.f. decreases causing an increase in motor current
The rotor strengthens the rotating field causing more motor current

Detailed SolutionAs the load is applied to a synchronous motor, the motor takes more armature current because

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