Synchronous Motor Quiz | Synchronous Motor Multiple Choice Questions and Answers
Questions
2
The power development by a synchronous motor will be maximum when the load angle is
Answer: 90 degree
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3
A synchronous machine is called a doubly excited machine because
Answer: Both its rotor and sator are excited
6
Ignoring the effects of armature reaction, if excitation of a synchronous motor running with constant load is decreased from its normal value, it leads to
Answer: Increase in both Ia and SYMBOL
8
A synchronous motor running with normal excitation adjusts to load increases essentially by increase in its
Answer: Armature current
9
An over-excited synchronous motor is used for
Answer: Power factor corrections
10
When the excitation of an unloaded salient pole synchronous motor suddenly gets disconnected
Answer: The motor stops
11
When load on a normally-excited synchronous motor is increased, its power factor tends to
Answer: Becomes increasingly lagging
12
When running under no-load condition and with normal excitation, armature current Ia drawn by a synchronous motor
Answer: Lags the applied voltage V by a small angle
13
When load on a synchronous motor running with normal excitation is increased, armature current drawn by it increases because
Answer: Net resultant voltage ER in armature is increased
14
When load on a synchronous motor is increased, its armature currents in increased provided it is
Answer: All of the above
15
The effect of increasing load on a synchronous motor running with normal excitation is to
Answer: Increase Ia but decrease p.f.
16
The V-curves of a synchronous motor show relationship between
Answer: D.C. field current and A.C. armature current
17
If the field of a synchronous motor is under excited, the power factor will be
Answer: Lagging
18
The maximum value of torque angle a in a synchronous motor is .......... degrees electrical
Answer: 90
19
In a synchronous motor, the magnitude of stator back e.m.f. Eb depends on
Answer: D.C. excitation only
20
The direction of rotation of a synchronous motor can be reversed by reversing
Answer: Supply phase sequence
