A. is amenable to better voltage control
B. is more stable
C. has exciting current independent of load current
D. has all above features
0
In a four-pole D.C. machine____________?
0
In lap winding, the number of brushes is always_____________?
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
0
The bearings used to support the rotor shafts are generally______________?
A. double the number of poles
B. same as the number of poles
C. half the number of poles
D. two
0
In D.C. generators, the cause of rapid brush wear may be___________?
A. ball bearings
B. bush bearings
C. magnetic bearmgs
D. needle bearings
0
For a D.C. generator when the number of poles and the number of armature conductors is fixed, then which winding will give the higher e.m.f___________ ?
A. severe sparking
B. rough commutator surface
C. imperfect contact
D. any of the above
0
Copper brushes in D.C. machine are used_____________?
A. Lap winding
B. Wave winding
C. Either of A. and B. above
D. Depends on other features of design
0
In case of D.C. machines, mechanical losses are primary function of____________?
A. where low voltage and high currents are involved
B. where high voltage and small cur-rents are involved
C. in both of the above cases
D. in none of the above cases
0
Fleming’s right-hand rule regarding direction of induced e.m.f., correlates__________?
A. current
B. voltage
C. speed
D. none of above