A. neutralise the commutating self induced e.m.f.
B. neutralise the armature reaction flux
C. neutralise both the armature reaction flux as well as commutating e.m.f. induced in the coil
D. perform none of the above functions
Related Mcqs:
- If B is the flux density, I the length of conductor and v the velocity of conductor, then induced e.m.f. is given by______________?
A. Blv
B. Blv2
C. Bl2v
D. Bl2v2 - 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 - In D.C. generators on no-load, the air gap flux distribution in space is______________?
A. sinusoidal
B. triangular
C. pulsating
D. flat topped - As a result of armature reaction, the reduction in the total mutual air gap flux in a D.C. generator is approximately______________?
A. 40 percent
B. 25 percent
C. 10 percent
D. 5 percent - Number of tappings for each equalizer ring is equal to_____________?
A. number of pole pairs
B. number of poles
C. number of parallel paths
D. number of commutator segments - In a commutator_____________?
A. copper is harder than mica
B. mica and copper are equally hard
C. mica is harder than copper
D. none of the above - D.C. generators are connected to the busbars or disconnected from them only under the floating condition________________?
A. to avoid sudden loading of the primemover
B. to avoid mechanicaljerk to the shaft
C. to avoid burning of switch contacts
D. all above - A cumulatively compounded long shunt generator when operating as a motor would be____________?
A. cumulatively compounded long shunt
B. deferentially compounded long shunt
C. cumulatively compounded short shunt
D. differentially compounded short shunt - Following D.C. generator will be in a position to build up without any residual magnetism in the poles______________?
A. series generator
B. shunt generator
C. compound generator
D. self-excited generator - If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be____________?
A. zero
B. small
C. the same as rated voltage
D. high
