Hi friends, these are objectives on electrical engineering emphasis on dc generator check out and comment if you have any doubts......
1) A dc series generator is employed
A) as a booster to maintain constant voltage at the load end of the feeder
B) for supplying traction load
C) for supplying industrial load at constant voltage
D) for battery charging
Ans:A
2) The essential condition for satisfactory parallel operation of two dc generators is that they should have the same
A) KW output rating
B) drooping voltage characteristics
C) percentage regulation
D) speed of operation
Ans:B
3) when two dc series generators are operating in parallel, an equalizer bar is used
A) to reduce armature reaction
B) to increase emf
C) to increase the speed
D) to reduce the flux
E) so that the two similar machines take approximately equal load current
Ans:E
4) In the case of parallel operation of dc compound wound generators, for proper division of load from no load to full load it is essential that they should have the same
A) KW output rating
B) percentage regulation
C) series field resistance
D) speed of operation
Ans:B
5) Two dc shunt generators having equal open circuit emfs but slight different load characteristics are operating in parallel, then
A) the machines will share load equally
B) the machine with more drooping characteristics will supply less load
C) the machine with more drooping characteristics will supply more load
Ans:B
6) An over-compounded dc generator is supplying 800 A at full load on 500V. The resistance of each conductor is 0.02 Ω. The percentage of compounding is
A) 1.6 %
B) 3.2 %
C) 6.4%
D) 12.8%
Ans:C
7) For a specific open circuit voltage of a dc generator, the short-circuit current will be maximum when it is
A) separately excited
B) shunt connected
C) cumulatively compounded
D) differentially compounded
Ans:C
8) A self excited dc shunt generator driven by its prime mover at the rated speed fails to build up voltage across its terminals at no-load. what reason can be assigned for this?
A) The field circuit resistance is higher than the critical resistance
B) The initial shunt field mmf does not assist the residual magnetism
C) one of the interpole connection is reversed
D) The brush-axis shifts slightly from the geometrical neutral axis of the machine
Ans:B
9) A dc shunt generator when driven without connecting field winding shows an open-circuit terminal voltage of 12 V. when field winding is connected and excited the terminal voltage drops to zero because
A) field resistance is higher than critical resistance
B) there is no residual magnetism in the field circuit
C) field winding has got wrongly connected
D) there is a fault in armature circuit
Ans:C
10) A dc shunt generator having a shunt field of 50 Ω was generating normally at 1000 rpm. The critical resistance of the machine was 80 Ω. Due to some reasons, the speed of the primeover became such that the generator just failed to generate. the speed at that time must have been
A) 1600 rpm
B) 800 rpm
C) 625 rpm
D) 500 rpm
Ans:C
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1) A dc series generator is employed
A) as a booster to maintain constant voltage at the load end of the feeder
B) for supplying traction load
C) for supplying industrial load at constant voltage
D) for battery charging
Ans:A
2) The essential condition for satisfactory parallel operation of two dc generators is that they should have the same
A) KW output rating
B) drooping voltage characteristics
C) percentage regulation
D) speed of operation
Ans:B
3) when two dc series generators are operating in parallel, an equalizer bar is used
A) to reduce armature reaction
B) to increase emf
C) to increase the speed
D) to reduce the flux
E) so that the two similar machines take approximately equal load current
Ans:E
4) In the case of parallel operation of dc compound wound generators, for proper division of load from no load to full load it is essential that they should have the same
A) KW output rating
B) percentage regulation
C) series field resistance
D) speed of operation
Ans:B
5) Two dc shunt generators having equal open circuit emfs but slight different load characteristics are operating in parallel, then
A) the machines will share load equally
B) the machine with more drooping characteristics will supply less load
C) the machine with more drooping characteristics will supply more load
Ans:B
6) An over-compounded dc generator is supplying 800 A at full load on 500V. The resistance of each conductor is 0.02 Ω. The percentage of compounding is
A) 1.6 %
B) 3.2 %
C) 6.4%
D) 12.8%
Ans:C
7) For a specific open circuit voltage of a dc generator, the short-circuit current will be maximum when it is
A) separately excited
B) shunt connected
C) cumulatively compounded
D) differentially compounded
Ans:C
8) A self excited dc shunt generator driven by its prime mover at the rated speed fails to build up voltage across its terminals at no-load. what reason can be assigned for this?
A) The field circuit resistance is higher than the critical resistance
B) The initial shunt field mmf does not assist the residual magnetism
C) one of the interpole connection is reversed
D) The brush-axis shifts slightly from the geometrical neutral axis of the machine
Ans:B
9) A dc shunt generator when driven without connecting field winding shows an open-circuit terminal voltage of 12 V. when field winding is connected and excited the terminal voltage drops to zero because
A) field resistance is higher than critical resistance
B) there is no residual magnetism in the field circuit
C) field winding has got wrongly connected
D) there is a fault in armature circuit
Ans:C
10) A dc shunt generator having a shunt field of 50 Ω was generating normally at 1000 rpm. The critical resistance of the machine was 80 Ω. Due to some reasons, the speed of the primeover became such that the generator just failed to generate. the speed at that time must have been
A) 1600 rpm
B) 800 rpm
C) 625 rpm
D) 500 rpm
Ans:C
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