1. Iron losses in a D.C. machine are independent of variations in_____________?
A. speed
B. load
C. voltage
D. speed and voltage
✅ The correct answer is option B.
D.C. Generators MCQs
2. A series generator can self-excite:______________?
A. only if the load current is zero
B. only if the load current is not zero
C. irrespective of the value of load current
D. none of the above
✅ The correct answer is option B.
3. 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 correct answer is option C.
4. According to Fleming’s right-hand rule for finding the direction of induced e.m.f., when middle finger points in the direction of induced e.m.f., forefinger will point in the direction of____________?
A. motion of conductor
B. lines of force
C. either of the above
D. none of the above
✅ The correct answer is option B.
5. 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
✅ The correct answer is option D.
6. The field coils of D.C. generator are usually made of_____________?
A. mica
B. copper
C. cast iron
D. carbon
✅ The correct answer is option B.
7. The commutator segments are connected to the armature conductors by means of___________?
A. copper lugs
B. resistance wires
C. insulation pads
D. brazing
✅ The correct answer is option A.
8. In a commutator_____________?
A. copper is harder than mica
B. mica and copper are equally hard
C. mica is harder than copper
D. none of the above
✅ The correct answer is option C.
9. While applying Fleming’s right-hand rule to And the direction of induced e.m.f., the thumb points towards___________?
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
✅ The correct answer is option D.
10. The resistance of armature winding depends on
A. length of conductor
B. cross-sectional area of the conductor
C. number of conductors
D. all of the above
✅ The correct answer is option D.