In D.C. generators, current to the external circuit from armature is given through_____________?

Related Mcqs:

1. 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

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. 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

4. Two generators are running in parallel. One of the generators may run as motor for which of the following reasons ?

   A. The direction of that generator is reversed
   B. The speed of that generator is increased
   C. The field of that generator is weakened
   D. That generator takes large share of loads

5. The following constitute short-circuit in the armature winding.

   A. Insulation failure between two commutator bars
   B. Insulation failure between two turns of a coil
   C. Two of more turns of the same coil getting grounded
   D. All of the above

6. In D.C. generators, the brushes on commutator remain in contact with conductors which_________________?

   A. lie under south pole
   B. lie under north pole
   C. lie under interpolar region
   D. are farthest from the poles

7. In D.C. generators, lap winding is used for______________?

   A. high voltage, high current
   B. low voltage, high current
   C. high voltage, low current
   D. low voltage, low current

8. When two D.C. series generators are running in parallel, an equilizer bar is used________________?

   A. to increase the speed and hence generated e.m.f.
   B. to increase the series flux
   C. so that two similar machines will pass approximately equal currents to the load
   D. to reduce the combined effect of ar-mature reaction of both machines

9. When two D.C. generators are running in parallel an equilizer bar is used______________?

   A. to increase the series flux
   B. to increase the generated e.m.f.
   C. to reduce the combined effect of ar-mature reaction of both the machines
   D. so that the two identical machines will pass approximately equal cur¬rents to the load

10. Shunt generators are most suited for stable parallel operation because of their______________?

    A. rising voltage characteristics
    B. identical voltage characteristics
    C. drooping voltage characteristics
    D. linear voltage characteristics