July 2018

A. abrasion from dust
B. excessive spring pressure
C. rough commutator bars
D. high mica insulation between com-mutation bars
E. all of the above factors

A. Dummy coils
B. Commutator
C. Eye bolt
D. Equilizer rings

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. 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

A. speed of armature
B. type of winding
C. voltage
D. amount of current to be collected

A. electromagnets
B. permanent magnets
C. both A. and B.
D. none of the above

A. the brushes of opposite polarity should track each other
B. the brushes of same polarity should track each other
C. brush position has no effect on the commutator grooving
D. None

A. reduces generator e.m.f.
B. increases armature speed
C. reduces interpoles flux density
D. results in sparking trouble

A. cumulatively compounded long shunt
B. deferentially compounded long shunt
C. cumulatively compounded short shunt
D. differentially compounded short shunt

A. along neutral axis
B. along field axis
C. in any of the above positions
D. in none of the above positions