Category: D.C. Generators
A. just ahead of magnetic neutral axis
B. in magnetic neutral axis
C. just behind the magnetic neutral axis
In any rotating machine that part which houses the conductors and in which e.m.f. induced is to be utilized is called____________?
A. mainly to reduce the eddy currents by providing local short-circuits
B. to provide path for the circulation of cooling air
C. to neutralise the cross-magnetising effect of the armature reaction
D. none of the above
A. external current
B. armature current
C. shunt current
D. load current
The main factor which leads to unstable parallel operation of flat and over compounded generators is_____________?
A. their rising voltage characteristics
B. unequal number of turns in their series field windings
C. unequal speed regulation of their primemovers
D. unequal series field resistances
Two D.C. shunt generators, each with armature resistance of 0.02 ohm and field resistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the load circuit. If their e.m.fs. are 270 V and 265 V, their bus bar voltage will be_____________________?
A. 270 V
B. 267.5 V
C. 265 V
D. 257.4 V
A. to increase the speed and hence generated e.m.f.
B. to increase the series flux
C. so that two similar machines will pass approximately equal currents to the load
D. to reduce the combined effect of ar-mature reaction of both machines
A. 100% regulation
B. infinite regulation
C. 50% regulation
D. 1% regulation