1. In a synchronous machine, if the field flux axis is ahead of the armature field axis, in the direction of rotation, the machine is working as ?

synchronous generator

asynchronous generator

synchronous motor

asynchronous motor

Answer: synchronous generator

Explanation:


2. The Poter's triangle separates the ?

stator voltage and rotor voltage

field m.m.f. and armature m.m.f.

armature leakage reactance and armature reaction m.m.f.

iron losses and copper losses

Answer: armature leakage reactance and armature reaction m.m.f.

Explanation:


3. In a large generator, dampers ?

reduce frequency fluctuations

reduce voltage fluctuations

increase stability

none of the above

Answer: increase stability

Explanation:


4. An exciter is a nothing but a ?

10°

30°

60°

90°

Answer: 60°

Explanation:


5. A lower voltage alternator, for the same power rating, will be ?

more costly

large in size

more efficient

operating at high r.p.m.

Answer: large in size

Explanation:


6. Alternators are usually designed to generate ?

definite currents

definite power factor

variable frequencies

definite frequencies

Answer: definite frequencies

Explanation:


7. An exciter for a generator is a ?

shunt motor

series motor

shunt generator

series generator

Answer: shunt generator

Explanation:


8. series generator ?

number of turns in coil

flux per pole

frequency of waveform

all of the above

Answer: all of the above

Explanation:


9. Which of the following is a prime mover ?

Steam turbine

Solar energy

Electric heater

None of the above

Answer: Steam turbine

Explanation:


10. The speed of a 4-pole 60 Hz synchronous machine will be ?

1800 r.p.m.

2400 r.p.m.

3000 r.p.m.

3600 r.p.m.

Answer: 1800 r.p.m.

Explanation: