Alternator MCQ | Synchronous Generator MCQ

41. A 50 Hz alternator will run at the highest speed if it is wound for

1. 8 poles
2. 6 poles
3. 4 poles
4. 2 poles

42. The frequency of voltage generated in a 4-pole alternator rotating at 1800 r.p.m. is

1. 25 Hz
2. 30 Hz
3. 60 Hz
4. None of these

43. If a four pole synchronous generator driven at 1500 rpm feeds a 6-pole induction motor, which is loaded to run at a slip of 5%, then the speed of the motor will be

1. 1000 rpm
2. 950 rpm
3. 1500 rpm
4. 1450 rpm

44. The phase angle introduced between the induced emf phasor, E and terminal voltage phasor, V during the load condition of an alternator is called-

1. Electric angle
2. Mechanical angle
3. Load angle
4. None of the above

45. The integration of a three-phase Alternator with the infinite grid requires which quantities to be same?

1. Voltage
2. Frequency
3. Phase sequence
4. All of the above

46. The capacity of large turbo-generators varies from

1. 20 to 100 MW
2. 50 to 30 MW
3. 70 to 400 MW
4. 100 to 650 MW

47. The full pitch coil in an alternator has a span of 18 slots and Coil span for fundamental flux wave is 17 slots. For third harmonic voltage, the coil span would be

1. 18 slots
2. 5 slots
3. 12 slots
4. 9 slots

48. The seventh space harmonic in the M.M.F. developed by balance fundamental-frequency armature currents rotate at X-times the synchronous speed with respect to poles, while

1. X= 5/7
2. X= 1/7
3. X= 8/7
4. X= 1

49. Fifth harmonic component of the induced voltage in the three-phase AC generator can be eliminated by using a winding pitch to

1. 2/3
2. 4/5
3. 5/6
4. 6/7

50. The reactive power generated by synchronous alternator can be controlled by?

1. changing the alternator speed
2. changing the prime move input
3. changing the terminal voltage
4. changing the field excitation