DC Generator MCQ Multiple Choice Questions - Page 4 for Practice

Q: 91. When two D.C. generators are running in parallel an equilizer bar is used

Correct Answer is: so that the two identical machines will pass approximately equal currents to the load

Q: 92. When two D.C. series generators are running in parallel, an equilizer bar is used

Correct Answer is: so that two similar machines will pass approximately equal currents to the load

Q: 93. The purpose of providing dummy coils in a generator is

Correct Answer is: to provide mechanical balance for the rotor

Q: 94. The function of pole shoes in the case of D.C. machine is

Correct Answer is: to discharge all the above functions

Q: 95. D.C. series generator is used

Correct Answer is: voltage at the toad end of the feeder

Q: 96. In a D.C. machine stray loss is the sum of

Correct Answer is: iron loss and mechanical loss

Q: 98. In a D.C. generator the ripples in the direct e.m.f. generated are reduced by

Correct Answer is: using carbon brushes of superior quality

Q: 99. In case of a flat compounded generator

Correct Answer is: voltage remains constant irrespecÂ¬tive of the load

Q: 100. For the parallel operation of two or more D.C. compound generators, we should ensurethat

Correct Answer is: series fields of all generators should be either on positive side or negative side of thearmature(e) all conditions mentioned above should be satisfied

Q: 102. Copper brushes in D.C. machine are used

Correct Answer is: where low voltage and high currents are involved

DC Generator MCQ Questions for Practice

91. When two D.C. generators are running in parallel an equilizer bar is used

to increase the series flux
to increase the generated e.m.f.
to reduce the combined effect of ar-mature reaction of both the machines
so that the two identical machines will pass approximately equal currents to the load

92. When two D.C. series generators are running in parallel, an equilizer bar is used

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

93. The purpose of providing dummy coils in a generator is

to reduce eddy current losses
to enhance flux density
to amplify voltage
to provide mechanical balance for the rotor

94. The function of pole shoes in the case of D.C. machine is

to reduce the reluctance of the magnetic path
to spread out the flux to achieve uniform flux density
to support the field coil
to discharge all the above functions

95. D.C. series generator is used

to supply traction load
to supply industrial load at constant voltage
voltage at the toad end of the feeder
for none of the above purpose

96. In a D.C. machine stray loss is the sum of

total copper loss and mechanical loss
armature copper loss and iron loss
shunt field copper loss and mechanical loss
iron loss and mechanical loss

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

40 percent
25 percent
10 percent
5 percent

98. In a D.C. generator the ripples in the direct e.m.f. generated are reduced by

using conductor of annealed copper
using commutator with large number of segments
using carbon brushes of superior quality
using equiliser rings

99. In case of a flat compounded generator

voltage generated is less than the rated voltage
generated voltage is proportional to the load on the generator
voltage remains constant irrespecÂ¬tive of the load
speed varies in proportion to the load on the generator

100. For the parallel operation of two or more D.C. compound generators, we should ensurethat

voltage of the incoming generator should be same as that of bus bar
polarity of incoming generator should be same as that of bus bar
all the series fields should be run in parallel by means of equilizer connection
series fields of all generators should be either on positive side or negative side of thearmature(e) all conditions mentioned above should be satisfied

101. Equilizer rings are required in case armature is

wave wound
lap wound
delta wound
duplex wound

102. Copper brushes in D.C. machine are used

where low voltage and high currents are involved
where high voltage and small cur-rents are involved
in both of the above cases
in none of the above cases

103. The open circuit voltage of a compound generator is 250 V. At full load the terminalvoltage

will be less than 250 V
will always be 250 V
may be greater or less than 250 V
none of the above

104. A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armaturevoltage wave

will be zero
will be of 5 Hz
willbeof5xiVHz
will be of v Hz 5

105. A 220 V D.C. generator is run at full speed without any excitation. The open circuitvoltage will be

zero
about 2 V
about 50 V
220 V

106. The e.m.f. induced in the armature of a shunt generator is 600 V. The armatureresistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be

640 V
620 V
600 V
580 V

107. If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed willbe

zero
small
the same as rated voltage
high