Synchronous Motor Multiple Choice Questions and Answers
46. In a synchronous motor, damper winding is provided in order to
A.Stabilize rotor motion
B.Suppress rotor oscillations
C.Develop necessary starting torque
D.Both (a) and (c)
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D.Both (a) and (c)
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47. While running, a synchronous motor is compelled to run at synchronous speed because of
A.Damper winding in its pole faces
B.Magnetic locking between stator and rotor poles
C.Induced e.m.f. in rotor field winding by stator flux
D.Complusion due to Lenz's law
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48. The speed regulation of a synchronous motor is always
A.1%
B.0.5%
C.Positive
D.Zero
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49. The operating speed of a synchronous motor can be changed to new fixed value by
A.Changing the load
B.Changing the supply voltage
C.Changing frequency
D.Using brakes
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50. In a synchronous motor running with fixed excitation, when the load is increased three times, its torque angle becomes approximately
A.One-third
B.Twice
C.Thrice
D.Nine times
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