A. along neutral axis
B. along field axis
C. in any of the above positions
D. in none of the above positions
Related Mcqs:
- Open circuited armature coil of a D.C. machine is________________?
A. identified by the scarring of the commutator segment to which open circuited coil is connected
B. indicated by a spark completely around the commutator
C. both A. and (b)
D. none of the above - The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be_____________?
A. 640 V
B. 620 V
C. 600 V
D. 580 V - If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be________________?
A. demagnetisation only
B. cross magnetisation as well as mag¬netisation
C. crossmagnetisation as well as demagnetising
D. cross magnetisation only - In a D.C. generator in order to reduce sparking at brushes, the self-induced e.m.f. in the coil is neutralised by all of the following except______________?
A. interpoles
B. dummy coils
C. compensating winding
D. shifting of axis of brushes - Two generators A and B have 6-poles each. Generator A has wave wound armature while generator B has lap wound armature. The ratio of the induced e.m.f. is generator A and B will be_______________?
A. 2 : 3
B. 3 : 1
C. 3 : 2
D. 1 : 3 - The following constitute short-circuit in the armature winding.
A. Insulation failure between two commutator bars
B. Insulation failure between two turns of a coil
C. Two of more turns of the same coil getting grounded
D. All of the above - Copper brushes in D.C. machine are used_____________?
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 - Brushes of D.C. machines are made of_________?
A. carbon
B. soft copper
C. hard copper
D. all of above - The material for commutator brushes is generally_______________?
A. mica
B. copper
C. cast iron
D. carbon - The number of brushes in a commutator depends on______________?
A. speed of armature
B. type of winding
C. voltage
D. amount of current to be collected
