A. length of conductor
B. cross-sectional area of the conductor
C. number of conductors
D. all of the above
The resistance of armature winding depends on Read More »
D.C. Generators A. mica
B. copper
C. cast iron
D. carbon
The field coils of D.C. generator are usually made of_____________? Read More »
D.C. Generators A. copper is harder than mica
B. mica and copper are equally hard
C. mica is harder than copper
D. none of the above
In a commutator_____________? Read More »
D.C. Generators A. motion of conductor
B. lines of force
C. either of the above
D. none of the above
A. direction of induced e.m.f.
B. direction of flux
C. direction of motion of the conductor if forefinger points in the direction of generated e.m.f.
D. direction of motion of conductor, if forefinger points along the lines of flux
A. rivets
B. counter sunk screws
C. brazing
D. welding
In D.C. generators the pole shoes are fastened to the pole core by_____________? Read More »
D.C. Generators A. magnetic flux, direction of current flow and resultant force
B. magnetic flux, direction of motion and the direction of e.m.f. induced
C. magnetic field strength, induced voltage and current
D. magnetic flux, direction of force and direction of motion of conductor
Fleming’s right-hand rule regarding direction of induced e.m.f., correlates__________? Read More »
D.C. Generators A. current
B. voltage
C. speed
D. none of above
In case of D.C. machines, mechanical losses are primary function of____________? Read More »
D.C. Generators 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
Copper brushes in D.C. machine are used_____________? Read More »
D.C. Generators A. Lap winding
B. Wave winding
C. Either of A. and B. above
D. Depends on other features of design
