A. electromagnets
B. permanent magnets
C. both A. and B.
D. none of the above
Related Mcqs:
- Two generators A and B have 6-poles each. Generator A has wave wound armature while generator B has lap wound armature. The ratio of the induced e.m.f. is generator A and B will be_______________?
A. 2 : 3
B. 3 : 1
C. 3 : 2
D. 1 : 3 - The series field of a short-shunt D.C. generator is excited by_______________?
A. external current
B. armature current
C. shunt current
D. load current - Which of the following components of a D.C, generator plays vital role for providing direct current of a D.C. generator ?
A. Dummy coils
B. Commutator
C. Eye bolt
D. Equilizer rings - 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 - If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be________________?
A. demagnetisation only
B. cross magnetisation as well as mag¬netisation
C. crossmagnetisation as well as demagnetising
D. cross magnetisation only - 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 - The field coils of D.C. generator are usually made of_____________?
A. mica
B. copper
C. cast iron
D. carbon - Flashing the field of D.C. generator means:______________?
A. neutralising residual magnetism
B. creating residual magnetism by a D.C. source
C. making the magnetic losses of forces parallel
D. increasing flux density by adding extra turns of windings on poles - In a D.C. generator in case the resistance of the field winding is increased, then output voltage will____________?
A. increase
B. decrease
C. remain unaffected
D. fluctuate heavily - A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave will_____________?
A. will be zero
B. will be of 5 Hz
C. will be of 5 xiVHz
D. will be of v Hz 5
