A Best Way To Crack Gorenment Job Exams

Electrical Engineering Objective Questions { DC Motors }

330. The e.m.f. generated by a shunt would D.C. generator is E. Now while pole flux remains constant, if the speed of the generator is doubled, the e.m.f. generated will be
A. E/2
C. slightly less than E
D. E
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331. In a D.C. generator the actual flux distribution depends upon
A. size of air gap
B. shape of the pole shoe
C. clearance between tips of the adjacent pole sh9es
D. all fo the above
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332. The armature core of a D.C. generator is usually made of
A. silicon steel
B. copper
C. non-ferrous material
D. cast-iron
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333. D.C. generator generates
A. a.c. voltage in the armature
B. d.c. voltage in the armature
C. a.c. superimposed over d.c.
D. none of the above
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334. Satisfactory commutation of D.C. machines requires
A. brushes should be of proper grade and size
B. brushes should smoothly run in the holders
C. smooth, concentric commutator properly undercut
D. all of the above
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335. Open circuited armature coil of a D.C. machine is
A. identified by the scarring of the commutator segment to which open circuited coil is connected
B. indicated by a spark completely around the commutator
C. both (a) and (b)
D. none of the above
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336. 1n a D.C. machine, fractional pitch winding is used
A. to increase the generated voltage
B. to reduce sparking
C. to save the copper because of shorter end connections
D. due to (b) and (c) above
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