Category: D.C. Generators
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
In a D.C. generator in order to reduce sparking at brushes, the self-induced e.m.f. in the coil is neutralised by all of the following except______________?
A. interpoles
B. dummy coils
C. compensating winding
D. shifting of axis of brushes
Which of the following generators will be preferred if they are required to be run in parallel?
A. Shunt generators
B. Series generators
C. Compound generators
D. None of the above
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
A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be_____________?
A. zero
B. about 2 V
C. about 50 V
D. 220 V
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
In D.C. generators the pole shoes are fastened to the pole core by_____________?
A. rivets
B. counter sunk screws
C. brazing
D. welding
Armature coil is short circuited by brushes when it lies_____________?
A. along neutral axis
B. along field axis
C. in any of the above positions
D. in none of the above positions
If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be________________?
A. demagnetisation only
B. cross magnetisation as well as mag¬netisation
C. crossmagnetisation as well as demagnetising
D. cross magnetisation only
The commutator segments are connected to the armature conductors by means of___________?
A. copper lugs
B. resistance wires
C. insulation pads
D. brazing
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