In a four-pole D.C. machine____________?
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
A separately excited generator as compared to a self-excited generator_____________?
A. is amenable to better voltage control
B. is more stable
C. has exciting current independent of load current
D. has all above features
In lap winding, the number of brushes is always_____________?
A. double the number of poles
B. same as the number of poles
C. half the number of poles
D. two
The bearings used to support the rotor shafts are generally______________?
A. ball bearings
B. bush bearings
C. magnetic bearmgs
D. needle bearings
In D.C. generators, the cause of rapid brush wear may be___________?
A. severe sparking
B. rough commutator surface
C. imperfect contact
D. any of the above
A. Lap winding
B. Wave winding
C. Either of A. and B. above
D. Depends on other features of design