A. imperfect brush contact
B. field resistance less than the critical resistance
C. no residual magnetism in the generator
D. faulty shunt connections tending to reduce the residual magnetism
Related Mcqs:
- If a self excited D.C. generator after being installed, fails to build up on its first trial run, the first thing to do is to______________?
A. reverse the field connections
B. increase the field resistance
C. increase the speed of primemover
D. check armature insulation resistance - 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 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 - A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be_____________?
A. zero
B. about 2 V
C. about 50 V
D. 220 V - Which of the following components of a D.C, generator plays vital role for providing direct current of a D.C. generator ?
A. Dummy coils
B. Commutator
C. Eye bolt
D. Equilizer rings - The e.m.f. generated by a shunt wound D.C. generator isE. Now while pole flux remains constant, if the speed of the generator is doubled, the e.m.f. generated will be_______________?
A. E/2
B. 2E
C. slightly less than E
D. E - Following D.C. generator will be in a position to build up without any residual magnetism in the poles______________?
A. series generator
B. shunt generator
C. compound generator
D. self-excited generator - To achieve sparkless commutation brushes of a D.C. generator are rockedm ahead so as to bring them?
A. just ahead of magnetic neutral axis
B. in magnetic neutral axis
C. just behind the magnetic neutral axis
D. none - In over compounded generator, full load terminal voltage is______________?
A. almost zero
B. less than no load terminal voltage
C. more than no load terminal voltage
D. equal to no-load terminal voltage - In a D.C. generator the critical resistance can be increased by_____________?
A. increasing its field resistance
B. decreasing its field resistance
C. increasing its speed
D. decreasing its speed
