The armature of D.C. generator is laminated to_______________?
(A) reduce the bulk
(B) provide the bulk
(C) insulate the core
(D) reduce eddy current loss
Laminations of core are generally made of________________?
(A) case iron
(B) carbon
(C) silicon steel
(D) stainless steel
Which of the following could be lamina-proximately the thickness of laminations of a D.C. machine ?
(A) 0.005 mm
(B) 0.05 mm
(C) 0.5 m
(D) 5 m
The commutator segments are connected to the armature conductors by means of___________?
(A) copper lugs
(B) resistance wires
(C) insulation pads
(D) brazing
Welding generator will have____________?
(A) lap winding
(B) wave winding
(C) delta winding
(D) duplex wave winding
Equilizer rings are required in case armature is_______________?
(A) wave wound
(B) lap wound
(C) delta wound
(D) duplex wound
Eddy currents are induced in the pole shoes of a D.C. machine due to______________?
(A) oscillating magnetic field
(B) pulsating magnetic flux
(C) relative rotation between field and armature
(D) all above
D.C. generators are connected to the busbars or disconnected from them only under the floating condition________________?
(A) to avoid sudden loading of the primemover
(B) to avoid mechanicaljerk to the shaft
(C) to avoid burning of switch contacts
(D) all above
Armature reaction of an unsaturated D.C. machine is_____________?
(A) crossmagnetising
(B) demagnetising
(C) magnetising
(D) none of above
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