Practice Test: Question Set - 03
1. Synchronizing power of a synchronous machine is
- (A) Directly proportional to the synchronous
reactance
- (B) Inversely proportional to the synchronous
reactance
- (C) Equal to the synchronous reactance
- (D) None of the above
2. When the voltage applied to a synchronous motor is increased, which of the following will reduce?
- (A) Stator flux
- (B) Pull in torque
- (C) Both (A) and (B)
- (D) None of the above
3. Which of the following methods is used to start a synchronous motor?
- (A) Damper winding
- (B) Star-delta starter
- (C) Damper winding in conjunction with star-delta
starter
- (D) Resistance starter in the armature circuit
4. Which of the following motors will be used in electric clocks?
- (A) D.C. shunt motor
- (B) D.C. series motor
- (C) A.C. induction motor
- (D) A.C. synchronous motor
5. Stability of a synchronous machine
- (A) Decreases with increase in its excitation
- (B) Increases with increase in its excitation
- (C) Remains unaffected with increase in
excitation
- (D) Any of the above
6. A rotary converter can also be run as a
- (A) D.C. shunt motor
- (B) D.C. series motor
- (C) D.C. compound motor
- (D) Synchronous motor
7. The effect of increasing the load on a synchronous motor running with normal excitation is to
- (A) Decrease both armature current and power
factor
- (B) Decrease armature current but increase power
factor
- (C) Increase armature current but decrease power
factor
- (D) Increase both its armature current and power factor
8. In a synchronous motor, V-curves represent relation between
- (A) Armature current and field current
- (B) Power factor and speed
- (C) Field current and speed
- (D) Field current and power factor
9. In a synchronous motor, the damping winding is generally used to
- (A) Prevent hunting and provide the starting torque
- (B) Reduce the eddy currents
- (C) Provide starting torque only
- (D) Reduce noise level
10. The duration of sudden snort-circuit test on a synchronous motor is usually about
- (A) One hour
- (B) One minute
- (C) One second
- (D) None of the above
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