DC GENERATORS

Question 1

1. The basic requirements of a DC armature winding is that it must be
   A. A closed one
   B. A lap winding
   C. A wave winding
   D. Either B or C

Answer 1

A. A close one

Question 2

2. A wave winding must go atleast ____ around the armature before it closes back where it started.
   A. Once
   B. Twice
   C. Thrice
   D. Four times

Answer 2

B. Twice

Question 3

3. The DC armature winding which coil sides are a pole pitch apart is called ____winding.
   A. Multiplex
   B. Fractional pitch
   C. Full pitch
   D. Pole pitch

Answer 3

C. Full pitch

Question 4

4. For making a coil span equal to a pole pitch in the armature winding of DC generator, the back pitch of the winding must be equal to the number of
   A. Commutator bars per pole
   B. Winding elements
   C. Armature conductors per path
   D. Armature parallel paths

Answer 4

A. Commutator bars per pole

Question 5

30. The sole purpose of a commutator in a DC generator is to
    A. Increase output voltage
    B. Reduce sparking at brushes
    C. Provide smoother output
    D. Convert the induced AC into DC

Answer 5

D. Convert the induced AC into DC

Question 6

6. Lap winding is suitable for current, ___ voltage DC generators.
   A. High, low
   B. Low, high
   C. Low, low
   D. High, high

Answer 6

A. High, low

Question 7

7. The series field of a short shunt DC generator is excited by ___ currents.
   A. Shunt
   B. Armature
   C. Load
   D. External

Answer 7

C. Load

Question 8

8. In a DC generator, the generated emf is directly proportional to the
   A. Field current
   B. Pole Flux
   C. Number of armature parallel paths
   D. Number of dummy coils

Answer 8

B. Pole Flux

Question 9

9. In DC generator l, armature reaction us produced actually by
   A. It’s field current
   B. Armature conductors
   C. Field pole winding
   D. Load current in armature

Answer 9

D. Load current in armature

Question 10

10. In DC generator, the effect of armature reaction on the main pole Flux is to
    A. Reduce it
    B. Distort it
    C. Reverse it
    D. Both A and B

Answer 10

D. Both A and B

Question 11

36. The most likely cause of sparking at the brushes in a DC machine is
    A. Open coil in armature
    B. Defective interpoles
    C. Incorrect brush spring pressure
    D. All of the above

Answer 11

D. All of the above

Question 12

12. Shunt generator are most suited for suitable parallel operation because of their voltage characteristics
    A. Identical
    B. Dropping
    C. Linear
    D. Rising

Answer 12

B. Dropping

Question 13

Two parallel shunt generators will divide the total load equally in proportion to their kW output ratings only when they have the same
A. Rated Voltage
B. Voltage Regulations
C. Internal voltage drops
D. Both A and B

Answer 13

D. Both A and B

Question 14

14. The voltage regulation if an overcompound DC generator is always
    A. Positive
    B. Negative
    C. Zero
    D. High

Answer 14

B. Negative

Question 15

15. It has the poorest voltage regulation
    A. Series generator
    B. Long shunt compound generator
    C. Shunt generator
    D. Short shunt compound generator

Answer 15

A. Series generator