Working Principle & Starting Methods Of Synchronous Motor - MCQs
Q1. If a three phase windings displaced in space by 120 degree in a synchronous motor then the magnitude of resultant flux when it is rotated by Θ = 0 degree and Θ = 60 degree isa. 0, 1.5 times the magnitude of maximum flux
b. 1.5 times the magnitude of maximum flux, 0
c. 0.866 times the magnitude of maximum flux, 1.5 times the magnitude of maximum flux
d. 1.5 times the magnitude of maximum flux, 1.5 times the magnitude of maximum flux
View Answer / Hide AnswerANSWER: d. 1.5 times the magnitude of maximum flux, 1.5 times the magnitude of maximum flux
Q2. For a half cycle of fluxes in a synchronous motor, the resultant flux has rotated througha. 0 degree
b. 90 degree
c. 180 degree
d. 360 degree
View Answer / Hide AnswerQ3. For a two pole, 50 Hz, 3 phase synchronous motor the speed of rotating magnetic field isa. 1000 rpm
b. 2000 rpm
c. 3000 rpm
d. 3500 rpm
View Answer / Hide AnswerQ4. A synchronous motor draws 2 MVA at a power factor of 0.8 leading. If the efficiency developed in the motor is 90% then the power developed is equal toa. 1212 kW
b. 1440 kW
c. 1676 kW
d. 1767 kW
View Answer / Hide AnswerQ5. Synchronous motor works on the principle ofa. Mutual induction
b. Electromagnetic induction
c. Magnetic locking
d. None of these
View Answer / Hide AnswerANSWER: c. Magnetic locking
Q6. Synchronous motors area. Self starting
b. Not self starting
View Answer / Hide AnswerANSWER: b. Not self starting
Q7. Can synchronous motor rotate at any speed other than the synchronous speed?a. Yes
b. No
View Answer / Hide AnswerQ8. The method used for starting synchronous motor is/area. Using pony motors
b. Using damper windings
c. As a slip ring induction motor
d. All of the above
View Answer / Hide AnswerANSWER: d. All of the above
Q9. A synchronous motor is started by using damper winding. When the motor will run at synchronous speed then the induced emf in the damper winding will bea. Zero
b. Maximum
c. Half of the terminal voltage
d. None of these
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