The reason for using compensating winding is

 81. The voltage regulation of a DC generator is defined as—

A) $\frac{V_{no-load} - V_{full-load}}{V_{full-load}} \times 100\%$
B) $\frac{V_{full-load} - V_{no-load}}{V_{full-load}} \times 100\%$
C) $\frac{V_{full-load}}{V_{no-load}} \times 100\%$
D) None
✅ Answer: A
Explanation: Regulation = (No-load voltage – Full-load voltage)/Full-load voltage × 100%.

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82. A cumulatively compounded generator has voltage–current characteristics that—
A) Rise with load
B) Fall with load
C) Remain constant
D) First rise then fall
✅ Answer: D
Explanation: Initially rises due to series field strengthening, then slightly falls due to armature reaction.

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83. Differentially compounded generators are rarely used because—
A) Their voltage decreases rapidly with load
B) Efficiency is too high
C) Field control is difficult
D) They are expensive
✅ Answer: A
Explanation: Differential compounding opposes main field, causing unstable output.

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84. When two DC shunt generators operate in parallel, the load sharing depends on—
A) Their speed
B) Their voltage characteristics and droop
C) The brush material
D) Field resistance only
✅ Answer: B
Explanation: Load sharing depends on voltage–current characteristics and droop (voltage drop with load).

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85. In parallel operation, if one generator has slightly higher voltage—
A) It will take more load
B) It will take less load
C) It will share equally
D) It will run in reverse
✅ Answer: A
Explanation: Higher terminal voltage generator supplies more current.

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86. Two DC series generators cannot be operated in parallel because—
A) Voltage increases with load
B) Load sharing is unstable
C) They have different field resistances
D) Speed is too high
✅ Answer: B
Explanation: In series generators, an increase in load current increases emf → cumulative effect → instability.

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87. The compounding level in a DC generator can be adjusted by—
A) Diverter across series field
B) Speed variation
C) Changing pole number
D) Brush shift
✅ Answer: A
Explanation: A diverter (shunt resistance) across series field controls compounding degree.

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88. For lighting loads, the preferred generator is—
A) Cumulatively compounded
B) Differentially compounded
C) Series
D) Shunt
✅ Answer: A
Explanation: Cumulative compound generator maintains nearly constant voltage with varying load.

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89. The brush shift in the direction of rotation results in—
A) Advanced commutation
B) Retarded commutation
C) No effect
D) Flux increase
✅ Answer: B
Explanation: Brush shift in direction of rotation delays current reversal → sparking.

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90. The efficiency of a DC generator can be determined by—
A) Swinburne’s test
B) Hopkinson’s test
C) Brake test
D) All of the above
✅ Answer: D
Explanation: All methods can be used: Swinburne (no-load), Hopkinson (back-to-back), brake (direct).

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91. Swinburne’s test is a—
A) No-load test
B) Full-load test
C) Half-load test
D) Short-circuit test
✅ Answer: A
Explanation: Swinburne’s test is a constant loss, no-load test.

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92. Hopkinson’s test on DC machines requires—
A) Two identical machines
B) One machine only
C) Three-phase supply
D) Alternator coupling
✅ Answer: A
Explanation: Two identical DC machines are mechanically coupled and electrically connected for back-to-back test.

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93. Stray load losses in a DC generator are—
A) Losses due to nonuniform current distribution and flux distortion
B) Copper losses
C) Hysteresis losses
D) Mechanical losses
✅ Answer: A
Explanation: Stray load losses arise due to irregular current and flux, typically 1% of output.

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94. If a DC generator runs at half the rated speed, its generated emf will be—
A) Half
B) Double
C) Same
D) Zero
✅ Answer: A
Explanation: $E ∝ N$, so emf halves when speed halves.

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95. A separately excited generator can build up voltage only if—
A) External DC supply is given to field winding
B) Residual magnetism is high
C) Load is connected
D) Armature reaction is strong
✅ Answer: A
Explanation: It requires external excitation for field current.

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96. In a shunt generator, as load increases, field current—
A) Decreases
B) Increases
C) Constant
D) Zero
✅ Answer: A
Explanation: Voltage drop reduces field current, weakening the field.

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97. The percentage efficiency of a DC generator at full load is 88%. At half load, it will be approximately—
A) 90%
B) 86%
C) 80%
D) 70%
✅ Answer: B
Explanation: Efficiency slightly decreases at lower load due to constant losses.

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98. The brush contact drop per brush in small generators is around—
A) 0.5–1.0 V
B) 2–3 V
C) 5 V
D) 10 V
✅ Answer: A
Explanation: Typical brush drop ≈ 0.5 to 1.0 V per brush for small machines.

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99. For same armature current, wave winding produces—
A) More emf
B) Less emf
C) Same emf
D) Higher torque
✅ Answer: A
Explanation: Wave winding has fewer parallel paths → higher emf for same current.

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100. The induced emf in a generator depends on—
A) Flux per pole and speed
B) Field current only
C) Armature resistance
D) Brush drop
✅ Answer: A
Explanation: $E ∝ ΦN$, directly proportional to flux and speed.

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101. The residual magnetism in DC generator is generally—
A) 1–4% of full rated flux
B) 10%
C) 25%
D) Zero
✅ Answer: A
Explanation: A small portion of flux (1–4%) remains even without excitation.

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102. When a DC generator is loaded, its speed—
A) Remains same
B) Slightly decreases
C) Increases sharply
D) Doubles
✅ Answer: B
Explanation: Load increases torque demand, slightly reducing speed.

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103. The output equation of a DC generator is—
A) $E = \frac{PΦZN}{60A}$
B) $P_{out} = VI$
C) $P_{out} = T × ω$
D) All of the above
✅ Answer: D
Explanation: All equations represent emf and power relationships in generator operation.

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104. Which loss does not occur at no-load?
A) Armature copper loss
B) Iron loss
C) Mechanical loss
D) Field copper loss
✅ Answer: A
Explanation: No armature current at no-load → no I²R loss in armature.

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105. Armature reaction effect is directly proportional to—
A) Armature current
B) Field current
C) Speed
D) Voltage
✅ Answer: A
Explanation: Armature reaction ∝ armature current.

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106. Neutral plane is defined as—
A) Plane where no emf is induced in armature coil
B) Plane of maximum emf
C) Plane perpendicular to flux
D) None
✅ Answer: A
Explanation: In neutral plane, emf = 0; brushes are placed here for sparkless commutation.

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107. The load curve of a DC generator shows—
A) Relation between terminal voltage and load current
B) Field current and emf
C) Speed and torque
D) Power factor vs current
✅ Answer: A
Explanation: Load characteristic: terminal voltage vs load current.

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108. When the generator load increases, armature reaction—
A) Increases
B) Decreases
C) Constant
D) None
✅ Answer: A
Explanation: Higher load → higher armature current → more armature reaction.

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109. The reason for using compensating winding is—
A) To neutralize armature mmf under pole faces
B) To increase torque
C) To reduce iron losses
D) To improve efficiency
✅ Answer: A
Explanation: Compensating winding counters armature mmf to maintain flux distribution.

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110. The function of the commutator is to—
A) Convert AC to DC
B) Transfer current to brushes
C) Reverse current direction in armature coil
D) All of the above
✅ Answer: D
Explanation: Commutator acts as mechanical rectifier, maintains unidirectional output, and transfers current via brushes.

The armature reaction in a generator causes flux

41. The commutator in a DC generator is made of—
A) Copper segments insulated by mica
B) Aluminum segments insulated by paper
C) Iron segments insulated by varnish
D) Carbon blocks joined together
✅ Answer: A
Explanation: Commutator consists of copper segments separated by thin mica insulation.

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42. The function of the armature winding is—
A) To produce magnetic flux
B) To carry the current where emf is induced
C) To hold the shaft
D) To cool the machine
✅ Answer: B
Explanation: The armature winding is where emf is induced and current is carried.

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43. The brushes in a DC generator are placed—
A) Along the neutral axis
B) Along the main field axis
C) Between pole shoes
D) At random
✅ Answer: A
Explanation: Brushes are located on the magnetic neutral axis (MNA) to minimize sparking.

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44. The load characteristic of a DC series generator is—
A) Rising initially then dropping
B) Constant
C) Linear
D) Drooping
✅ Answer: A
Explanation: Voltage first rises due to field strengthening, then drops due to saturation and losses.

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45. The voltage regulation of a DC generator is—
A) Always positive
B) Always negative
C) Zero
D) Can be positive or negative
✅ Answer: A
Explanation: Terminal voltage decreases with load; hence regulation is positive.

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46. The main function of pole shoe is—
A) To support the pole core
B) To spread magnetic flux uniformly
C) To increase speed
D) To collect current
✅ Answer: B
Explanation: Pole shoes spread the magnetic flux uniformly and reduce reluctance.

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47. For a given flux, if the speed of a DC generator is doubled, the generated emf—
A) Halves
B) Doubles
C) Becomes four times
D) Remains same
✅ Answer: B
Explanation: $E ∝ N$; if speed doubles, emf doubles.

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48. When the field current increases, generated emf—
A) Decreases
B) Increases
C) Remains constant
D) Becomes zero
✅ Answer: B
Explanation: More field current → more flux → higher emf.

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49. In a shunt generator, when load increases, terminal voltage—
A) Increases
B) Decreases
C) Remains same
D) First increases then decreases
✅ Answer: B
Explanation: Increased load causes more voltage drop in armature and field weakening.

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50. The copper losses in a DC generator vary as—
A) Constant
B) ∝ $I^2$
C) ∝ I
D) ∝ speed
✅ Answer: B
Explanation: Copper loss $= I^2 R$, depends on current squared.

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51. The iron losses in a DC generator are—
A) Constant for all loads
B) Proportional to current
C) Proportional to load
D) Negligible
✅ Answer: A
Explanation: Iron losses depend on flux and speed, nearly constant for a given speed.

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52. Mechanical losses include—
A) Bearing friction and windage losses
B) Hysteresis losses
C) Copper losses
D) Eddy current losses
✅ Answer: A
Explanation: Friction and windage constitute mechanical losses.

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53. The overall efficiency of a DC generator is—
A) Electrical output / Mechanical input
B) Mechanical output / Electrical input
C) Input / Output
D) None
✅ Answer: A
Explanation: $η = \frac{\text{Electrical output}}{\text{Mechanical input}} \times 100\%$

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54. If field resistance is greater than critical resistance—
A) Generator will not excite
B) Generator will excite faster
C) Terminal voltage will increase
D) Armature current will increase
✅ Answer: A
Explanation: Self-excitation fails if field resistance > critical resistance.

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55. Critical speed of a DC generator is—
A) Minimum speed for self-excitation
B) Maximum safe speed
C) Speed at which copper loss = iron loss
D) Rated speed
✅ Answer: A
Explanation: Critical speed is the minimum speed at which emf just builds up.

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56. The main cause of failure to build up voltage in a DC generator is—
A) Open field circuit
B) Wrong field connection
C) Loss of residual magnetism
D) Any of these
✅ Answer: D
Explanation: All above conditions can prevent voltage build-up.

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57. Residual magnetism in a generator can be restored by—
A) Flashing the field with a DC supply
B) Running at higher speed
C) Reducing load
D) Shorting field winding
✅ Answer: A
Explanation: Residual magnetism is restored by field flashing.

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58. The direction of rotation of a DC generator is reversed. The voltage polarity will—
A) Reverse
B) Remain same
C) Become zero
D) Fluctuate
✅ Answer: A
Explanation: Both rotation and field direction affect emf polarity (Fleming’s rule).

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59. The maximum efficiency occurs when—
A) Variable losses = constant losses
B) Armature current is maximum
C) Speed is maximum
D) Field current is minimum
✅ Answer: A
Explanation: For max efficiency, variable (Cu) losses equal constant (core + mech) losses.

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60. The armature reaction reduces—
A) Terminal voltage
B) Generated emf
C) Flux per pole
D) All of these
✅ Answer: D
Explanation: Armature reaction weakens flux and causes voltage drop.

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61. The brushes are made of carbon because—
A) Low friction, good conductivity
B) High friction
C) Light weight only
D) Insulating property
✅ Answer: A
Explanation: Carbon provides low friction and self-lubrication.

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62. In a DC generator, the direction of induced emf is given by—
A) Fleming’s right-hand rule
B) Fleming’s left-hand rule
C) Lenz’s law
D) Ampere’s rule
✅ Answer: A
Explanation: Right-hand rule gives direction of emf.

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63. Commutation means—
A) Current reversal in armature coil
B) Voltage reversal
C) Load change
D) Flux change
✅ Answer: A
Explanation: Commutation is the process of current reversal in armature coil.

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64. The sparkless commutation can be achieved by—
A) Interpoles
B) Compensating winding
C) Both A and B
D) None
✅ Answer: C
Explanation: Interpoles and compensating windings reduce sparking.

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65. The no-load characteristic is also known as—
A) Magnetization characteristic
B) Load characteristic
C) Efficiency curve
D) Voltage regulation curve
✅ Answer: A
Explanation: OCC = Magnetization curve = No-load characteristic.

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66. The shape of OCC curve is—
A) Initially linear then flat
B) Hyperbolic
C) Straight line
D) Constant
✅ Answer: A
Explanation: Linear at first, then flattens due to saturation.

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67. In a shunt generator, the field winding has—
A) Many turns of thin wire
B) Few turns of thick wire
C) Thick conductors
D) None
✅ Answer: A
Explanation: Shunt field: many turns, high resistance, small current.

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68. In a series generator, the field winding has—
A) Few turns of thick wire
B) Many turns of thin wire
C) High resistance
D) None
✅ Answer: A
Explanation: Series field: few turns, low resistance, high current.

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69. Compensating winding is placed—
A) In pole shoes
B) On yoke
C) On armature
D) On shaft
✅ Answer: A
Explanation: Compensating windings are embedded in pole faces to oppose armature reaction.

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70. Voltage build-up in a shunt generator fails if—
A) Residual magnetism is lost
B) Field connection reversed
C) Field resistance too high
D) All of the above
✅ Answer: D
Explanation: All these prevent self-excitation.

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71. The load test on a DC generator is used to determine—
A) Efficiency and regulation
B) Commutation
C) Mechanical losses only
D) No-load losses
✅ Answer: A
Explanation: Load test determines efficiency and voltage regulation.

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72. The back emf in a generator is—
A) In opposition to rotation
B) In phase with supply
C) Independent of flux
D) Zero
✅ Answer: A
Explanation: The induced emf always opposes the cause producing it.

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73. The terminal voltage can be increased by—
A) Increasing field current
B) Increasing load
C) Decreasing speed
D) Decreasing field flux
✅ Answer: A
Explanation: More field current → more flux → higher emf.

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74. In a compound generator, both field windings are—
A) Connected in series
B) One in series, one in parallel
C) Both in parallel
D) On the same circuit
✅ Answer: B
Explanation: Compound = shunt (parallel) + series (series) fields.

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75. A DC compound generator used for lighting load is—
A) Cumulatively compounded
B) Differentially compounded
C) Series type
D) Shunt type
✅ Answer: A
Explanation: Cumulative compounding keeps voltage nearly constant.

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76. The brushes should make contact—
A) At the neutral plane
B) At the pole axis
C) At 90° to rotation
D) Anywhere
✅ Answer: A
Explanation: Neutral plane minimizes sparking.

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77. Eddy current losses can be reduced by—
A) Laminating the core
B) Increasing flux density
C) Using thick iron sheets
D) Using copper core
✅ Answer: A
Explanation: Laminations restrict eddy current paths.

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78. Hysteresis loss per unit volume =
A) η × Bmax^1.6 × f
B) k × Bmax^1.6 × f
C) Bmax × f
D) 2B × f
✅ Answer: B
Explanation: Steinmetz’s law: $Ph = k B_{max}^{1.6} f$

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79. A DC generator can be run as—
A) DC motor
B) AC motor
C) Induction motor
D) Stepper motor
✅ Answer: A
Explanation: DC machine is reversible; generator ↔ motor.

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80. The armature reaction in a generator causes flux—
A) To shift in direction of rotation
B) To shift opposite to rotation
C) To increase
D) To decrease
✅ Answer: A
Explanation: Flux shifts in direction of rotation due to armature reaction

Lap winding is used for

 11. In a DC shunt generator, the field winding is connected—

A) In series with the armature
B) In parallel with the armature
C) In series with the load
D) Across commutator segments
✅ Answer: B
Explanation: In a shunt generator, field winding is connected across the armature (in parallel).

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12. The terminal voltage of a DC generator is—
A) Equal to induced emf
B) Less than induced emf
C) More than induced emf
D) Zero when load is connected
✅ Answer: B
Explanation: Terminal voltage = Induced emf − Voltage drop in armature and brushes.

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13. The armature reaction in DC generator causes—
A) Increase in main flux
B) Distortion and weakening of main flux
C) Strengthening of field flux
D) No effect on flux
✅ Answer: B
Explanation: Armature reaction distorts and weakens the main magnetic field.

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14. The effect of armature reaction can be reduced by—
A) Increasing armature current
B) Decreasing field current
C) Using compensating winding
D) Decreasing speed
✅ Answer: C
Explanation: Compensating windings neutralize the effect of armature reaction.

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15. The commutation process converts—
A) DC to AC
B) AC to DC
C) DC to pulsating DC
D) AC to pulsating DC
✅ Answer: B
Explanation: Commutation in a DC generator converts AC induced emf into unidirectional DC output.

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16. Poor commutation results in—
A) Sparking at brushes
B) Reduced speed
C) Reduced emf
D) Increase in flux
✅ Answer: A
Explanation: Poor commutation causes sparking due to delayed current reversal.

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17. Interpoles in a DC generator are used to—
A) Improve efficiency
B) Reduce armature reaction and improve commutation
C) Increase speed
D) Decrease field current
✅ Answer: B
Explanation: Interpoles provide a neutralizing flux that aids commutation.

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18. The load characteristic of a DC shunt generator is—
A) Drooping
B) Rising
C) Flat
D) Constant
✅ Answer: A
Explanation: Due to voltage drop with load, the characteristic is slightly drooping.

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19. In a DC series generator, the field winding carries—
A) Only armature current
B) Only field current
C) Load current
D) Shunt current
✅ Answer: C
Explanation: In a series generator, the same current flows through armature, field, and load.

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20. For self-excitation in a DC generator, the condition is—
A) Residual magnetism + correct polarity + field resistance < critical resistance
B) Field resistance > critical resistance
C) No residual magnetism required
D) Field disconnected from armature
✅ Answer: A
Explanation: Self-excitation occurs if the field resistance is below critical value.

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21. Critical field resistance is—
A) The minimum resistance for shunt field
B) The maximum resistance at which the generator just excites
C) Always constant
D) Independent of speed
✅ Answer: B
Explanation: It’s the maximum field resistance for which the generator can self-excite.

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22. The open-circuit characteristic (OCC) of a DC generator is—
A) Straight line
B) Curved
C) Horizontal line
D) Hyperbolic
✅ Answer: B
Explanation: OCC is a nonlinear curve due to magnetic saturation.

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23. In a DC generator, if the speed increases, the generated emf—
A) Increases
B) Decreases
C) Remains constant
D) First increases then decreases
✅ Answer: A
Explanation: $E ∝ N$, emf is directly proportional to speed.

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24. The losses in a DC generator are—
A) Copper losses
B) Iron losses
C) Mechanical losses
D) All of the above
✅ Answer: D
Explanation: Total losses include copper, iron (core), and mechanical losses.

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25. The efficiency of a DC generator is maximum when—
A) Variable losses = Constant losses
B) Copper loss = Iron loss
C) Field loss = Armature loss
D) Load current = Maximum
✅ Answer: A
Explanation: Efficiency is maximum when variable losses equal constant losses.

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26. A cumulatively compounded DC generator gives—
A) Rising voltage with load
B) Falling voltage with load
C) Constant voltage
D) Zero voltage
✅ Answer: A
Explanation: Cumulative compounding strengthens the field with load current, improving voltage.

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27. The brush contact drop per brush is approximately—
A) 0.2 V
B) 1–2 V
C) 5 V
D) 0.02 V
✅ Answer: B
Explanation: Typically around 1–2 V per brush depending on current and material.

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28. The terminal voltage of a DC series generator—
A) Increases with load
B) Decreases with load
C) Remains constant
D) First increases then decreases
✅ Answer: D
Explanation: Initially increases due to more field current, but later drops due to armature reaction.

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29. The magnetization curve of a DC generator is plotted between—
A) Field current and load current
B) Field current and generated emf
C) Speed and torque
D) Voltage and current
✅ Answer: B
Explanation: The magnetization curve shows the relation between field current and induced emf.

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30. The main disadvantage of a DC series generator is—
A) Poor voltage regulation
B) High cost
C) High speed
D) Low current
✅ Answer: A
Explanation: Series generators have poor voltage regulation, so rarely used for power supply.

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31. A differential compound generator is not used because—
A) It has unstable voltage
B) It is costly
C) It requires high speed
D) It gives low current
✅ Answer: A
Explanation: Differential compounding opposes main field, making voltage unstable.

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32. The armature of a DC generator is—
A) Stationary
B) Rotating
C) Both stationary and rotating
D) None
✅ Answer: B
Explanation: Armature is the rotating part where emf is induced.

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33. The field system of a DC generator is—
A) Stationary
B) Rotating
C) Commutating
D) Alternating
✅ Answer: A
Explanation: Field poles are stationary and mounted on the yoke.

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34. The function of yoke in a DC machine is—
A) To provide mechanical support and magnetic path
B) To house armature winding
C) To act as a commutator
D) To carry brushes
✅ Answer: A
Explanation: The yoke provides mechanical strength and completes the magnetic circuit.

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35. The material used for yoke is—
A) Cast iron or steel
B) Aluminum
C) Copper
D) Brass
✅ Answer: A
Explanation: Yoke is made of cast iron for small machines or cast steel for large ones.

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36. The number of parallel paths in a wave-wound DC generator is—
A) Equal to number of poles
B) Always two
C) Equal to half of poles
D) Equal to twice the poles
✅ Answer: B
Explanation: In wave winding, number of parallel paths = 2, irrespective of poles.

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37. In lap winding, the number of parallel paths is—
A) 2
B) Equal to number of poles
C) Half the number of poles
D) Double the number of poles
✅ Answer: B
Explanation: In lap winding, number of parallel paths = number of poles (A = P).

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38. Wave winding is generally used for—
A) High current, low voltage generators
B) Low current, high voltage generators
C) Constant speed machines
D) Variable speed machines
✅ Answer: B
Explanation: Wave winding gives high voltage, low current output.

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39. Lap winding is used for—
A) Low current, high voltage
B) High current, low voltage
C) High speed
D) None
✅ Answer: B
Explanation: Lap winding provides large current capacity due to more parallel paths.

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40. The commutator segments are insulated by—
A) Mica
B) Paper
C) Plastic
D) Wood
✅ Answer: A
Explanation: Mica is used as insulation between commutator segments due to high dielectric strength.

The direction of induced emf in a DC generator is given by

 1. The basic principle of a DC generator is—

A) Coulomb’s law
B) Faraday’s laws of electromagnetic induction
C) Lenz’s law
D) Ampere’s law
✅ Answer: B
Explanation: A DC generator works on Faraday’s law of electromagnetic induction, which states that an emf is induced when a conductor cuts magnetic flux.

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2. The energy conversion in a DC generator is—
A) Electrical to Mechanical
B) Mechanical to Electrical
C) Chemical to Electrical
D) Thermal to Electrical
✅ Answer: B
Explanation: In a DC generator, the prime mover provides mechanical energy which is converted into electrical energy.

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3. The part of the DC generator which converts AC into DC is—
A) Field winding
B) Commutator
C) Armature winding
D) Brush
✅ Answer: B
Explanation: The commutator acts as a mechanical rectifier converting the alternating emf induced in the armature to unidirectional (DC) output.

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4. The function of brushes in a DC generator is to—
A) Collect current from commutator
B) Produce magnetic field
C) Support the armature
D) Provide cooling
✅ Answer: A
Explanation: Brushes are made of carbon and used to collect current from the commutator to the external circuit.

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5. The material used for brushes in DC machines is usually—
A) Copper
B) Aluminum
C) Carbon or Graphite
D) Iron
✅ Answer: C
Explanation: Carbon brushes are used because they provide good conductivity and self-lubrication.

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6. The armature core of a DC generator is laminated to—
A) Reduce copper losses
B) Reduce eddy current losses
C) Reduce hysteresis losses
D) Increase mechanical strength
✅ Answer: B
Explanation: Laminating the core minimizes eddy current losses.

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7. The emf equation of a DC generator is—
A) $E = (PΦZN) / (60A)$
B) $E = (PZN) / (60ΦA)$
C) $E = (ΦZN) / (60P)$
D) $E = (60A) / (PΦZN)$
✅ Answer: A
Explanation:
$E = \frac{PΦZN}{60A}$,
where P = poles, Φ = flux per pole, Z = total conductors, N = speed (rpm), A = parallel paths.

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8. In a DC generator, the residual magnetism is—
A) Necessary for self-excitation
B) Harmful for machine operation
C) Removed by short-circuiting
D) Constant during operation
✅ Answer: A
Explanation: Residual magnetism provides the initial emf required for self-excitation.

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9. The direction of induced emf in a DC generator is given by—
A) Fleming’s right-hand rule
B) Fleming’s left-hand rule
C) Lenz’s law
D) Joule’s law
✅ Answer: A
Explanation: Fleming’s right-hand rule gives the direction of induced emf in a generator.

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10. The main types of DC generators are—
A) Shunt, Series, Compound
B) Lap, Wave, Ring
C) Core, Shell, Toroidal
D) Inductive, Capacitive, Resistive
✅ Answer: A
Explanation: DC generators are classified based on field winding connections into Shunt, Series, and Compound types.