Question 1 of 56

1. 37. What is the property of wave winding in DC generators?

Low current, low voltage

Low current, high voltage

High current, high voltage

High current, low voltage

Question 1 of 56

Question 2 of 56

2. 16. How are interpoles connected in a DC generator?

In parallel with the armature

In series with the shunt field

In series with the armature

In parallel with the shunt field

Question 2 of 56

Question 3 of 56

3. 26. What is the name of the generator if its field is connected in parallel with the armature?

Series generator

Compound generator

Shunt generator

Self-excited generator

Question 3 of 56

Question 4 of 56

4. 27. What is the purpose of pole shoes in a DC generator?

Spread flux uniformly in the air gap

Reduce air gap

Minimize magnetic losses

Increase field strength

Question 4 of 56

Question 5 of 56

5. 50. What is the effect of armature reaction in DC generators?

Decreased output voltage

Zero output voltage

Pulsating output voltage

Increased output voltage

Question 5 of 56

Question 6 of 56

6. 28. What is the function of split rings in a DC generator?

Maintain constant voltage

Collect current unidirectionally

Reduce voltage drop at brushes

Increase terminal voltage beyond rated

Question 6 of 56

Question 7 of 56

7. 42. Which voltage is induced dynamically in a DC generator?

Direct current voltage

Alternating voltage

Pulsating voltage

Oscillating voltage

Question 7 of 56

Question 8 of 56

8. 34. Which method improves insulation resistance in DC generators?

Periodic machine heating

Regular commutator cleaning

Frequent brush replacement

Blowing hot air during maintenance

Question 8 of 56

Question 9 of 56

9. 36. Which DC generator is used for arc welding?

Shunt generator

Differential compound generator

Cumulative compound generator

Series generator

Question 9 of 56

Question 10 of 56

10. 17. What is the necessity of residual magnetism in a self-excited DC generator?

To reduce armature current

To build up the voltage

To reduce the field current

To maintain constant output voltage

Question 10 of 56

Question 11 of 56

11. 29. Which material is used to make brushes in generators?

Aluminium and graphite

Carbon and graphite

Steel and graphite

Cast iron and graphite

Question 11 of 56

Question 12 of 56

12. 9. What is the name of the DC generator's field where the series field opposes the shunt field?

Cumulative compound generator

Long shunt compound generator

Differential compound generator

Short shunt compound generator

Question 12 of 56

Question 13 of 56

13. What is the name of the DC generator described as having cumulative short shunt compounding?

Differential short shunt compound

Cumulative long shunt compound

Differential long shunt compound

Cumulative short shunt compound

Question 13 of 56

Question 14 of 56

14. 35. Which DC generator works without residual magnetism?

Series generator

Compound generator

Shunt generator

Separately excited generator

Question 14 of 56

Question 15 of 56

15. 51. Calculate the EMF generated in a 4-pole, simplex wave-wound DC generator with 1020 conductors at 1500 rpm and 0.007 Wb flux/pole.

178 V

428 V

357 V

243 V

Question 15 of 56

Question 16 of 56

16. 49. What happens if shunt field resistance exceeds critical value in a DC generator?

Normal voltage buildup

Above-normal output voltage

Pulsating output voltage

Voltage buildup failure

Question 16 of 56

Question 17 of 56

17. 4. Which formula is used to calculate the generated emf in a DC generator?

B

C

D

A

Question 17 of 56

Question 18 of 56

18. 43. What is the purpose of the slot marked 'X' in a DC generator?

Fix the keyway

Lubrication

Easy shaft removal

Enable air circulation

Question 18 of 56

Question 19 of 56

19. 33. Which DC generator is used for long-distance distribution lines?

Shunt generator

Cumulative compound generator

Series generator

Differential compound generator

Question 19 of 56

Question 20 of 56

20. 52. How is armature reaction neutralized in large DC generators?

Resistance wires in windings

Additional interpoles

Compensating winding

Increased brush contact resistance

Question 20 of 56

Question 21 of 56

21. 22. Why is the armature resistance of a DC generator kept very low?

Reduce armature current

Reduce armature voltage drop

Run armature with less weight

Reduce temperature of armature

Question 21 of 56

Question 22 of 56

22. 24. Why is compensating winding provided in large DC generators?

Connect more loads

Reduce commutation effect

Increase generator efficiency

Neutralize armature reaction effect

Question 22 of 56

Question 23 of 56

23. 48. What is the purpose of compensating winding in DC generators?

Minimize rough commutation

Decrease field coil excitation current

Maintain constant output voltage

Neutralize demagnetizing effect

Question 23 of 56

Question 24 of 56

24. 1. What is the name of the part marked as 'X' in a DC generator?

Commutator segment

Brush

Commutator riser

Armature core

Question 24 of 56

Question 25 of 56

25. 7. What is the name of the DC generator that requires separate excitation?

Separately excited generator

Compound generator

Shunt generator

Series generator

Question 25 of 56

Question 26 of 56

26. 44. What is the purpose of field coils in a DC generator?

Increase magnetic path reluctance

Reduce magnetizing current

Increase air gap flux

Magnetize poles to produce flux

Question 26 of 56

Question 27 of 56

27. 32. Why does terminal voltage decrease with increased load in a DC shunt generator?

Reduced brush voltage drop

Armature reaction effect

Increased armature resistance

Increased shunt field inductance

Question 27 of 56

Question 28 of 56

28. 55. What happens to induced EMF if main field flux distorts in a DC generator?

EMF decreases

EMF increases

EMF becomes zero

No change in EMF

Question 28 of 56

Question 29 of 56

29. 38. What is the purpose of resistance wire in commutator connections?

Nullify statically induced EMF

Increase statically induced EMF

Smooth current direction reversal

Maintain constant voltage

Question 29 of 56

Question 30 of 56

30. 3. Which rule is used to find the direction of induced emf in a DC generator?

Fleming's left hand rule

Fleming's right hand rule

Cork screw rule

Right hand palm rule

Question 30 of 56

Question 31 of 56

31. 14. How many parallel paths are there in a duplex lap winding of a 4-pole DC generator?

4

6

8

12

Question 31 of 56

Question 32 of 56

32. 20. What is the name of the compound generator if the shunt field is connected in parallel with the armature?

Differential compound

Short shunt compound

Cumulative compound

Long shunt compound

Question 32 of 56

Question 33 of 56

33. 21. Why is the armature core of a DC generator laminated?

Reduce eddy current loss

Reduce copper loss

Reduce hysteresis loss

Reduce friction loss

Question 33 of 56

Question 34 of 56

34. 45. Which metal is used for pole cores in large DC generators?

Cast iron

Soft iron

Cast steel

Stainless steel

Question 34 of 56

Question 35 of 56

35. 54. Calculate the induced EMF of a 4-pole, lap-wound dynamo at 1000 rpm with 600 conductors and 0.064 Wb flux/pole.

320 V

480 V

160 V

640 V

Question 35 of 56

Question 36 of 56

36. 25. What is the reason a DC generator fails to build up voltage?

Prime mover running above rated speed

Loose brush contact

Field resistance above critical value

High armature resistance

Question 36 of 56

Question 37 of 56

37. 13. What is the name of the part of a DC generator that provides mechanical support and a path for magnetic flux?

Stator

Pole core

Yoke (or frame)

Pole shoes

Question 37 of 56

Question 38 of 56

38. 11. What is the formula for dynamically induced emf?

BLV volts

BLV cosθ volts

BL sinθ volts

BLV sinθ volts

Question 38 of 56

Question 39 of 56

39. 46. Why are pole core stampings laminated in DC generators?

Reduce hysteresis loss

Reduce windage loss

Reduce friction loss

Reduce eddy current loss

Question 39 of 56

Question 40 of 56

40. 47. Which DC generator is used for electroplating?

Cumulative compound generator

Shunt generator

Series generator

Differential compound generator

Question 40 of 56

Question 41 of 56

41. 8. Which type of energy is converted into electrical energy by a generator?

Chemical energy

Heat energy

Kinetic energy

Mechanical energy

Question 41 of 56

Question 42 of 56

42. 5. What is the formula to calculate back emf of a DC motor?

C

A

B

D

Question 42 of 56

Question 43 of 56

43. 31. How does the magnetic circuit complete through the yoke and poles in a generator?

Laminated pole core

Armature winding conductors

Armature core

Field coils

Question 43 of 56

Question 44 of 56

44. 19. Which voltage drop is indicated in the portion marked as 'X' in a DC generator?

Armature reaction drop

Full load voltage drop

Shunt field voltage drop

Armature voltage drop

Question 44 of 56

Question 45 of 56

45. 56. What causes heavy sparking in DC generator brushes?

Excessive brush spring tension

Short circuit in field winding

Shift in MNA and GNA positions

Short circuit in armature winding

Question 45 of 56

Question 46 of 56

46. 18. Which two points measure the brush contact resistance in DC machines?

Resistance between brush and commutator

Resistance between brush and commutator riser

Resistance between brush and armature conductors

Resistance between the opposite brushes

Question 46 of 56

Question 47 of 56

47. 10. What is the principle of a DC generator?

Fleming’s left hand rule

Fleming’s right hand rule

Faraday’s laws of electromagnetic induction

Cork screw rule

Question 47 of 56

Question 48 of 56

48. 30. Why do DC generators lose residual magnetism?

Frequent direction changes of rotation

Heavy short circuit in load

Continuous no-load running

Uninterrupted operation

Question 48 of 56

Question 49 of 56

49. 23. Why should a DC generator run only in the clockwise direction?

Protect brushes from damage

Avoid generator overloading

Protect residual magnetism

Avoid short circuit in armature

Question 49 of 56

Question 50 of 56

50. 39. Why are solid pole shoes used in DC generators?

Decrease residual magnetism

Increase residual magnetism

Reduce magnetic path reluctance

Reduce copper loss

Question 50 of 56

Question 51 of 56

51. 53. What happens if a DC generator is idle for a long time?

Field coil resistance increases

Loss of residual magnetism

Armature resistance increases

Increased armature reaction

Question 51 of 56

Question 52 of 56

52. 40. Which metal is used for large-capacity DC generator yokes?

Rolled steel

Cast iron

Soft iron

Aluminium

Question 52 of 56

Question 53 of 56

53. 15. Name the part of a DC generator that consists of thin laminated sheets to reduce eddy currents.

Commutator segment

Side end plates

Pole shoe lamination

Armature core lamination

Question 53 of 56

Question 54 of 56

54. 12. Which rule is used to find the direction of a magnetic field?

Right hand palm rule

Fleming’s left hand rule

Fleming’s right hand rule

Cork screw rule

Question 54 of 56

Question 55 of 56

55. 6. What is the name of the part marked 'X' in a DC generator (pole assembly)?

Pole shoe

Pole tip

Pole core

Pole coil

Question 55 of 56

Question 56 of 56

56. 41. What is the function of split rings in a DC generator?

Collect output from alternate conductors

Unidirectional output

Opposite direction output

Continuous output supply

Question 56 of 56