In a D.C. generator the critical resistance refers to the resistance of_____________?

Related Mcqs:

1. The critical resistance of the D.C. generator is the resistance of_____________?

   A. field
   B. brushes
   C. armature
   D. load

2. 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

3. In a D.C. generator the critical resistance can be increased by_____________?

   A. increasing its field resistance
   B. decreasing its field resistance
   C. increasing its speed
   D. decreasing its speed

4. Which of the following components of a D.C, generator plays vital role for providing direct current of a D.C. generator ?

   A. Dummy coils
   B. Commutator
   C. Eye bolt
   D. Equilizer rings

5. 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

6. The field coils of D.C. generator are usually made of_____________?

   A. mica
   B. copper
   C. cast iron
   D. carbon

7. 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

8. In a D.C. generator in case the resistance of the field winding is increased, then output voltage will____________?

   A. increase
   B. decrease
   C. remain unaffected
   D. fluctuate heavily

9. Two D.C. shunt generators, each with armature resistance of 0.02 ohm and field resistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the load circuit. If their e.m.fs. are 270 V and 265 V, their bus bar voltage will be_____________________?

   A. 270 V
   B. 267.5 V
   C. 265 V
   D. 257.4 V

10. Flashing the field of D.C. generator means:______________?

    A. neutralising residual magnetism
    B. creating residual magnetism by a D.C. source
    C. making the magnetic losses of forces parallel
    D. increasing flux density by adding extra turns of windings on poles