DC Generator Multiple Choice Questions and Answers

11. In D.C. generators, current to the external circuit from armature is given through

1. commutator
2. solid connection
3. slip rings
4. none of above

12. Which of the following could be lamina-proximately the thickness of laminations of a D.C. machine ?

1. 0.005 mm
2. 0.05 mm
3. 0.5 m
4. 5 m

13. Which of the following statement about D.C. generators is false ?

1. Compensating winding in a D.C. machine helps in commutation
2. In a D. C. generator interpoles winding is connected in series with the armaturewinding
3. Back pitch and front pitch are both odd and approximately equal to the pole pitch
4. Equilizing bus bars are used with parallel running of D.C. shunt generators

14. In a commutator

1. copper is harder than mica
2. mica and copper are equally hard
3. mica is harder than copper
4. none of the above

15. The commutator segments are connected to the armature conductors by means of

1. copper lugs
2. resistance wires
3. insulation pads
4. brazing

16. Armature reaction of an unsaturated D.C. machine is

1. crossmagnetising
2. demagnetising
3. magnetising
4. none of above

17. A cumulatively compounded long shunt generator when operating as a motor would be

1. cumulatively compounded long shunt
2. differentially compounded long shunt
3. cumulatively compounded short shunt
4. differentially compounded short shunt

18. In case of D.C. machines, mechanical losses are primary function of

1. current
2. voltage
3. speed
4. none of above

19. With a D.C. generator which of the following regulation is preferred ?

1. 100% regulation
2. infinite regulation
3. 50% regulation
4. 1% regulation

20. Armature reaction in a generator results in

1. demagnetisation of leading pole tip and magnetisation of trailing pole tip
2. demagnetisation of trailing pole tip and magnetisation of leading pole tip
3. damagnetising the centre of all poles
4. magnetising the centre of all poles