electrical

DC Generator MCQ Objective Questions and Answers Page - 4

1.

The commutator of a dc motor serves the purpose of

Answer/ Hint      

Answer : B

Explanation :

2.

In a dc machine, the brushes are physically placed in the

Answer/ Hint      

Answer : A

Explanation :

3.

In dc machines , the armature windings are placed on the rotor because of the necessity for

Answer/ Hint      

Answer : C

Explanation :

4.

Wave winding is employed in a dc machine of

Answer/ Hint      

Answer : B

Explanation :

5.

If two 8 –pole dc machines of identical armatures are wound, one with lap winding and the other with wave winding , then

Answer/ Hint      

Answer : D

Explanation :

6.

The armature resistance in case of lap wound armature having Z conductors  each conductor of length  /  metres, x-sectional area a m2, resistivity and P poles will be

Answer/ Hint      

Answer : A

Explanation :

7.

In lap winding , the number of brushes is always _______the number of poles

Answer/ Hint      

Answer : B

Explanation :

8.

A P-Pole lap wound dc machine had an armature current Ia. The conductor current in the armature winding is

Answer/ Hint      

Answer : B

Explanation :

9.

A lap wound dc machine has 400 conductors and 8 poles. The voltage induced per conductor is 2V. The machine generates a voltage of

Answer/ Hint      

Answer : A

Explanation :

10.

A 4 pole generator with 16 coils has a two layer lap winding. The pole pitch is

Answer/ Hint      

Answer : C

Explanation :

11.

When the shunt field of a dc compound generator is connected across both the series filed and armature . Such a connection is known as

Answer/ Hint      

Answer : B

Explanation :

12.

The series field of a short shunt dc generator is excited by ___________

Answer/ Hint      

Answer : C

Explanation :

13.

The slight curvature at the lower end of the OCC of a self-excited dc generator is due to

Answer/ Hint      

Answer : B

Explanation :

14.

The fall in speed of a dc generator due to increase in load can be corrected by

Answer/ Hint      

Answer : D

Explanation :

15.

The magnetic field which initially induces emf in the armature in a self excited dc generator is because of

Answer/ Hint      

Answer : C

Explanation :

16.

A generator may losse residual magnetism due to

Answer/ Hint      

Answer : A

Explanation :

17.

In dc generators the residual magnetism is of the order of

Answer/ Hint      

Answer : A

Explanation :

18.

In comparison to self excited generator, a separately excited generator

Answer/ Hint      

Answer : D

Explanation :

19.

The voltage at the terminals of a dc series generator running at rated rpm and no load will be

Answer/ Hint      

Answer : C

Explanation :

20.

A dc series generator is provided with divertor an is delivering its rated current. If the divertor switch is opened, the terminal voltage will

Answer/ Hint      

Answer : C

Explanation :

21.

A 4 pole , 25 kW, 200 V wave wound dc shunt generator the current in each parallel path will be

Answer/ Hint      

Answer : A

Explanation :

22.

A dc shunt generator is supplying load of 1.8 kW at 200 V . Its armature and filed resistances are 0.4Ω and 200 Ω respectively . What is the generated emf  ?

Answer/ Hint      

Answer : C

Explanation :

23.

If the field circuit resistance of a dc shunt generator exceeds its critical value, the generator

Answer/ Hint      

Answer : A

Explanation :

24.

A shunt generator has a critical field resistance of 200 Ω at a speed of 800 rpm. If the speed of the generator is increased to 1,000 rpm what is the change in the critical field resistance of th

Answer/ Hint      

Answer : C

Explanation :

25.

The factor that is not responsible for drop in terminal voltage of a dc shunt generator on load is

Answer/ Hint      

Answer : A

Explanation :

26.

In a dc shunt generator , the voltage build up is generally restricted due to

Answer/ Hint      

Answer : C

Explanation :

27.

An ideal dc generator has a regulation of _____ per cent

Answer/ Hint      

Answer : A

Explanation :

28.

The  terminal voltage of an over compounded dc generator

Answer/ Hint      

Answer : B

Explanation :

29.

In a dc compound generator , “flat compound” characteristic required for certain application, may be obtained by connecting a variable resistance:

Answer/ Hint      

Answer : A

Explanation :

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