Synchronous generator or alternator is one of the most popular electrical machines. It is found at the power stations and is synchronized with a turbine whose rotation causes its rotor to rotate and generate electric power at the output. Given below are the top 10 MCQs on synchronous generators.

1. Synchronous generator is also known as:

  1. Conservator
  2. Alternator
  3. Fluctuator
  4. Amplifier

Correct answer: 2


2. Rotor winding in alternator is also known as:

  1. Field winding
  2. Armature Winding
  3. Protruding winding
  4. None of these

Correct answer: 1


3. For generating 50 Hz power, a 4 pole generator should turn at:

  1. 1500 r/min
  2. 2000 r/min
  3. 24000 r/min
  4. 48000 r/min

Correct answer: 1.

Explanation: Speed = (120 * f)/P

Speed = 120 * 50 / 4 = 1500 r/min


4. The condition which should be met for paralleling generators:

  1. Same phase sequence
  2. RMS line voltages should be equal
  3. Frequency of oncoming generator should be slightly higher
  4. All of these

Correct answer: 4


5. The behavior of the synchronous generator greatly depends on:

  1. Power factor of load
  2. Speed of its rotor
  3. Core losses
  4. None of these

Correct answer: 1


6. Addition of lagging load to a stand alone synchronous generator:

  1. Increases terminal voltage
  2. Decreases terminal voltage
  3. Slightly increases terminal voltage
  4. Has no impact on terminal voltage

Correct answer: 2


7. Armature reaction can be mathematically expressed by equation:

  1. -jX.IA
  2. jX.I
  3. R.IA
  4. None of above

Correct answer: 1


8. Short circuit ratio is defined as the: ratio of the field current required for the rated voltage at _______________ to the field current required for the rated armature current at the short circuit:

  1. open circuit, short circuit
  2. open circuit, open circuit
  3. short circuit, short circuit
  4. short circuit, open circuit

Correct answer: 1


9. Stator winding in alternator is also known as:

  1. Field winding
  2. Armature Winding
  3. Protruding winding
  4. None of these

Correct answer: 2


10. A generator with a service factor of 1.2 can be operated at ______ percent of rated load:

  1. 80%
  2. 100%
  3. 120%
  4. 150%

Correct answer: 3.