A. all the four poles are north poles
B. alternate poles are north and south
C. all the four poles are south poles
D. two north poles follow two south poles
Related Mcqs:
- In D.C. generators the pole shoes are fastened to the pole core by_____________?
A. rivets
B. counter sunk screws
C. brazing
D. welding - In case of a 4-pole D.C. generator provided with a two layer lap winding with sixteen coils, the pole pitch will be__________________?
A. 4
B. 8
C. 16
D. 32 - Eddy currents are induced in the pole shoes of a D.C. machine due to______________?
A. oscillating magnetic field
B. pulsating magnetic flux
C. relative rotation between field and armature
D. all above - The function of pole shoes in the case of D.C. machine is______________?
A. to reduce the reluctance of the mag¬netic path
B. to spread out the flux to achieve uniform flux density
C. to support the field coil
D. to discharge all the above functions - The e.m.f. generated by a shunt wound D.C. generator isE. Now while pole flux remains constant, if the speed of the generator is doubled, the e.m.f. generated will be_______________?
A. E/2
B. 2E
C. slightly less than E
D. E - The number of armature parallel paths in a two-pole D.C. generator having duplex lap winding is______________?
A. 2
B. 4
C. 6
D. 8 - Iron losses in a D.C. machine are independent of variations in______________?
A. speed
B. load
C. voltage
D. speed and voltage - The demagnetising component of armature reaction in a D.C. generator___________?
A. reduces generator e.m.f.
B. increases armature speed
C. reduces interpoles flux density
D. results in sparking trouble - In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when_______________?
A. there is no load on|he generator
B. the generator runs on full load
C. the generator runs on overload
D. the generator runs on designed speed - A series generator can self-excite:______________?
A. only if the load current is zero
B. only if the load current is not zero
C. irrespective of the value of load current
D. none of the above
