A Best Way To Crack Gorenment Job Exams

Electrical Engineering Objective Questions { DC Motors }



344.  In D.C. generators the polarity of the interpoles
A. is the same as that of the main pole ahead
B. is the same as that of the immediately preceding pole
C. is opposite to that of the main pole ahead
D. is neutral as these poles do not play part in generating e.m.f.
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345.  The e.m.E generated in a D.C. generator is directly proportional to
A. flux/pole
B. speed of armature
C. number of poles
D. all of the above
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346.  In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when
A. there is no load on the generator
B. the generator runs on full load
C. the generator runs on overload
D. the generator runs on designed speed
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347.  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
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348. 1n D.C. generator on no-load, the air gap flux distribution in space is
A. sinusoidal
B. triangular
C. pulsating
D. flat topped
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349.  A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.E will be nearly
A. 150 V
B. 175 V
C. 240 V
D. 290 V
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350.  The purpose of providing dummy coils in a generator is
A. to reduce eddy current losses
B. to enhance flux density
C. to amplify voltage
D. to provide mechanical balance for the rotor
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