As a result of armature reaction, the reduction in the total mutual air gap flux in a D.C. generator is approximately______________?

Related Mcqs:

1. Two generators A and B have 6-poles each. Generator A has wave wound armature while generator B has lap wound armature. The ratio of the induced e.m.f. is generator A and B will be_______________?

   A. 2 : 3
   B. 3 : 1
   C. 3 : 2
   D. 1 : 3

2. The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be_____________?

   A. 640 V
   B. 620 V
   C. 600 V
   D. 580 V

3. The e.m.f. generated by a shunt wound D.C. generator isE. Now while pole flux remains constant, if the speed of the generator is doubled, the e.m.f. generated will be_______________?

   A. E/2
   B. 2E
   C. slightly less than E
   D. E

4. In a separately excited generator supplying rated load the armature reaction.

   A. is always present
   B. is always absent
   C. may be sometimes present
   D. none of the above

5. Armature reaction in a generator results in_____________?

   A. demagnetisation of leading pole tip and magnetisation of trailing pole tip
   B. demagnetisation of trailing pole tip and magnetisation of leading pole tip
   C. damagnetising the center of all poles
   D. magnetising the center of all poles

6. In D.C. generators on no-load, the air gap flux distribution in space is______________?

   A. sinusoidal
   B. triangular
   C. pulsating
   D. flat topped

7. For a D.C. generator when the number of poles and the number of armature conductors is fixed, then which winding will give the higher e.m.f___________ ?

   A. Lap winding
   B. Wave winding
   C. Either of A. and B. above
   D. Depends on other features of design

8. The armature core of a D.C. generator is usually made of__________________?

   A. silicon steel
   B. copper
   C. non-ferrous material
   D. cast-iron

9. A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave will_____________?

   A. will be zero
   B. will be of 5 Hz
   C. will be of 5 xiVHz
   D. will be of v Hz 5

10. The number of armature parallel paths in a two-pole D.C. generator having duplex lap winding is______________?

    A. 2
    B. 4
    C. 6
    D. 8