Engineering/ Engineering Electrical Engineering Dc Motors part1 Sample Test,Sample questions

Question:
.A direct on line starter is used: for starting motors

1.iip to 5 H.P.

2.up to 10 H.P.

3.up to 15 H.P.

4.up to 20 H.P.


Question:
.If I2 be the armature currentthen speed of a D.C. shunt motor isindependent of Ia

1.independent of Ia

2.proportional to la

3.varies as (Ia)

4.varies as la


Question:
.In a D.C. shunt motorspeed is

1.independent of armature current

2.directly proportional to the armature current

3.proportional to the square of the current

4.inversely proportional to the armature current


Question:
.In a D.C. shunt motorunder the conditions of maximum powerthe current in the armature will be

1.almost negligible

2.rated full-load current

3.less than full-load current

4.more than full-load current


Question:
.In case of D.C. shunt motors the speed is dependent on back e.m.f. only because

1.back e.m.f. is equal to armature drop

2.armature drop is negligible

3.flux is proportional to armature current

4.flux is practically constant in D:C. shunt motors


Question:
.The current drawn by the armature of D.C. motor is directly proportional to

1.the torque required

2.the speed of the motor

3.the voltage across the terminals

4.none of the above


Question:
.The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is

1.4

2.2

3.1

4.0.5


Question:
.Which of the following method of speed control of D.C. machine will offer minimum efficiency ?

1.Voltage control method

2.Field control method

3.Armature control method

4.All above methods


Question:
.Which one of the following is not the function of pole shoes in a D.C. machine ?

1.To reduce eddy current loss

2.To support the field coils

3.To spread out flux for better unifor-mity

4.To reduce the reluctance of the mag-netic path


Question:
A D.C. series motor is that which

1.has its field winding consisting of thick wire and less turns

2.has a poor torque

3.can be started easily without load

4.has almost constant speed


Question:
A three point starter is considered suitable for

1.shunt motors

2.shunt as well as compound motors

3.shuntcompound and series motors

4.all D.C. motors


Question:
By looking at which part of the motorit can be easily confirmed that a particular motor is D.C. motor?

1.Frame

2.Shaft

3.Commutator

4.Stator


Question:
Differentially compound D.C. motors can find applications requiring

1.high starting torque

2.low starting torque

3.variable speed

4.frequent on-off cycles


Question:
For starting a D.C. motor a starter is required because

1.it limits the speed of the motor

2.it limits the starting current to a safe value

3.it starts the motor

4.none of the above


Question:
If a D.C. motor is connected across the A.C. supply it will

1.run at normal speed

2.not run

3.run at lower speed

4.burn due to heat produced in the field winding by .eddy currents


Question:
If a D.C. motor is to be selected for conveyorswhich rriotor would be preferred ?

1.Series motor

2.Shunt motor

3.Differentially compound motor

4.Cumulative compound motor


Question:
If the supply voltage for a D.C. motor is increasedwhich of the following will decrease ?

1.Starting torque

2.Operating speed

3.Full-load current

4.All of the above


Question:
In a D.C. series motorif the armature current is reduced by 50%the torque of the motor will be equal to

1.100% of the previous value

2.50% of the previous value

3.25% of the previous value

4.10% of the previous value


Question:
In case of conductively compensated D.C. series motorsthe compensating winding is provided

1.as separately wound unit

2.in parallel with armature winding

3.in series with armature winding

4.in parallel with field winding


Question:
In case-the conditions for maximum power for a D.C. motor are establishedthe efficiency of the motor will be

1.100%

2.around 90%

3.anywhere between 75% and 90%

4.less than 50%


Question:
In D.C. machines fractional pitch winding is used

1.to improve cooling

2.to reduce copper losses

3.to increase the generated e.m.f.

4.to reduce the sparking


Question:
In D.C. motor which of the following can sustain the maximum temperature rise?

1.Slip rings

2.Commutator

3.Field winding

4.Armature winding


Question:
In D.C. shunt motors as load is reduced

1.the speed will increase abruptly

2.the speed will increase in proportion to reduction in load

3.the speed will remain almost/constant

4.the speed will reduce


Question:
Sparking at the commutator of a D.C. motor may result in

1.damage to commutator segments

2.damage to commutator insulation

3.increased power consumption

4.all of the above


Question:
Sparkingis discouraged in a D.C. motor because

1.it increases the input power con

2.commutator gets damaged

3.both (a) and (b)

4.none of the above


Question:
Speed control by Ward Leonard method gives uniform speed variation

1.in one direction

2.in both directions

3.below normal speed only

4.above normal speed only.


Question:
Starters are used with D.C. motors because

1.these motors have high starting torque

2.these motors are not self-starting

3.back e.m.f. of these motors is zero initially

4.to restrict armature current as there is no back e.m.f. while starting


Question:
The condition for maximum power in case of D.C. motor is

1.back e.m.f. = 2 x supply voltage

2.back e.m.f. = | x supply voltage

3.supply voltage = | x back e.m.f.

4.supply voltage = back e.m.f.


Question:
The direction of rotation of a D.C. series motor can be changed by

1.interchanging supply terminals

2.interchanging field terminals

3.either of (a) and (b) above

4.None of the above


Question:
The power mentioned on the name plate of an electric motor indicates

1.the power drawn in kW

2.the power drawn in kVA

3.the gross power

4.the output power available at the shaft


Question:
The ratio of starting torque to full-load torque is least in case of

1.series motors

2.shunt motor

3.compound motors

4.none of the above


Question:
The speed of a D.C. motor can be varied by varying

1.field current

2.applied voltage

3.resistance in series with armature

4.any of the above


Question:
The speed of a D.C. series motor is

1.proportional to the armature current

2.proportional to the square of the armature current

3.proportional to field current

4.inversely proportional to the armature current


Question:
The speed of a D.C. shunt motor more than its full-load speed can be obtained by

1.decreasing the field current

2.increasing the field current

3.decreasing the armature current

4.increasing the armature current


Question:
The starting resistance of a D.C. motor is generally

1.low

2.around 500 Q

3.1000 Q

4.infinitely large


Question:
The type of D.C. motor used for shears and punches is

1.shunt motor

2.series motor

3.differential compoutid D.C. motor

4.cumulative compound D.C. motor


Question:
These days D.C. motors are widely used in

1.pumping sets

2.air compressors

3.electric traction

4.machine shops


Question:
To get the speed of D.Cmotor below the normal without wastage of electrical energy is used.

1.Ward Leonard control

2.rheostatic control

3.any of the above method

4.none of the above method


Question:
What will happen if the back e.m.f. of a D.C. motor vanishes suddenly?

1.The motor will stop

2.The motor will continue to run

3.The armature may burn

4.The motor will run noisy


Question:
When two D.C. series motors are connected in parallelthe resultant speed is

1.more than the normal speed

2.loss than the normal speed

3.normal speed

4.zero


Question:
Which D.C. motor is generally preferred for cranes and hoists ?

1.Series motor

2.Shunt motor

3.Cumulatively compounded motor

4.Differentially compounded motor


Question:
Which D.C. motor is preferred for elevators ?

1.Shunt motor

2.Series motor

3.Differential compound motor

4.Cumulative compound motor


Question:
Which D.C. motor will be preferred for machine tools ?

1.Series motor

2.Shunt motor

3.Cumulative compound motor

4.Differential compound motor


Question:
Which D.C. motor will be suitable alongwith flywheel for intermittent light and heavy loads?

1.Series motor

2.Shunt motor

3.Cumulatively compounded motor

4.Differentially compounded motor


Question:
Which of the following application requires high starting torque ?

1.Lathe machine

2.Centrifugal pump

3.Locomotive

4.Air blower


Question:
Which of the following load normally needs starting torque more than the rated torque?

1.Blowers

2.Conveyors

3.Air compressors

4.Centrifugal pumps


Question:
Which of the following motor is preferred for operation in highly explosive atmosphere ?

1.Series motor

2.Shunt motor

3.Air motor

4.Battery operated motor


More MCQS

  1. Civil Engineering MCQS -Building Materials Section 1
  2. Civil Engineering MCQS -Building Materials Section 2
  3. Civil Engineering MCQS -Building Materials Section 3
  4. Civil Engineering MCQS -Building Materials Section 4
  5. Mechanical Engineering Engineering MCQS -Mechanics Section-1
  6. Mechanical Engineering Engineering MCQS -Mechanics Section-2
  7. Civil Engineering MCQS -Building Materials Section 5
  8. Civil Engineering MCQS -Building Materials Section 6
  9. Civil Engineering MCQS -Building Materials Section 7
  10. Civil Engineering MCQS -Building Materials Section 8
  11. Civil Engineering MCQS-Surveying Section 1
  12. Civil Engineering MCQS-Surveying Section 2
  13. Civil Engineering MCQS-Surveying Section 3
  14. Civil Engineering MCQS-Surveying Section 4
  15. Civil Engineering MCQS-Surveying Section 5
  16. Civil Engineering MCQS-Surveying Section 6
  17. Civil Engineering MCQS-Surveying Section 7
  18. Civil Engineering MCQS-Surveying Section 8
  19. Civil Engineering (MCQS) Soil Mechanics and Foundation Engineering SET 1
  20. Civil Engineering (MCQS) Soil Mechanics and Foundation Engineering SET 2
  21. Civil Engineering (MCQS) Soil Mechanics and Foundation Engineering SET 3
  22. Civil Engineering (MCQS) Soil Mechanics and Foundation Engineering SET 4
  23. Civil Engineering (MCQS) Soil Mechanics and Foundation Engineering SET 5
  24. Civil Engineering (MCQS) Soil Mechanics and Foundation Engineering SET 6
  25. Civil Engineering [MCQS] Applied Mechanics Section -1
  26. Civil Engineering [MCQS] Applied Mechanics Section -2
  27. Civil Engineering [MCQS] Applied Mechanics Section -3
  28. Civil Engineering [MCQS] Applied Mechanics Section -4
  29. Civil Engineering [MCQS] Applied Mechanics Section -5
  30. Civil Engineering -MCQS-Hydraulics Section 1
  31. Civil Engineering -MCQS-Hydraulics Section 2
  32. Civil Engineering -MCQS-Hydraulics Section 3
  33. Civil Engineering -MCQS-Hydraulics Section 4
  34. Civil Engineering -MCQS-Hydraulics Section 5
  35. Civil Engineering -MCQS-Hydraulics Section 6
  36. Civil Engineering -MCQS-Waste Water Engineering - Section 1
  37. Civil Engineering -MCQS-Waste Water Engineering - Section 2
  38. Civil Engineering -MCQS-Waste Water Engineering - Section 3
  39. Civil -MCQ RCC Structures Design - Section 1
  40. Civil -MCQ RCC Structures Design - Section 2
  41. Civil -MCQ RCC Structures Design - Section 3
  42. Engineering Electrical Engineering Dc Motors part1
  43. Engineering Electrical Engineering Dc Motors part 2
  44. Engineering Electrical Engineering Dc Motors part3
  45. Electric Drives MCQ Questions and Answers
  46. Automobile Engineering MCQ Set 01
  47. Automobile Engineering MCQ Set 02
  48. Automobile Engineering MCQ Set 03
  49. Compressors, Gas Turbines and Jet Engines MCQ Practice Test - Set 01
  50. Compressors, Gas Turbines and Jet Engines MCQ Practice Test - Set 02
  51. Compressors, Gas Turbines and Jet Engines MCQ Practice Test - Set 03
  52. Compressors, Gas Turbines and Jet Engines MCQ Practice Test - Set 04
  53. Machine Design Mcq set 01
  54. Machine Design Mcq set 02
  55. Machine Design Mcq set 3
  56. Mechanical Engineering Design MCQ SET 03
  57. Mechanical Engineering Design MCQ SET 04
  58. Advanced Surveying mcq set 1
  59. Automobile Engineering MCQ
  60. Basic Civil Engineering Mcq
  61. Microwave Engineering Mcq Set 1
  62. Microwave Engineering Mcq Set 2
  63. Microwave Engineering Mcq Set 3
  64. Mechanical Engineering Basic Mcq Questions Set 1
  65. Mechanical Engineering Basic Mcq Questions Set 2
  66. Basic Chemical Engineering MCQ
  67. Chemical Engineering MCQ Question Set 1
  68. Chemical Engineering Mcq Question Set 2
  69. Chemical Engineering Mcq Question Set 3
  70. Chemical Engineering Mcq Question Set 4
  71. Chemical Engineering Mcq Question Set 5
  72. Chemical Engineering Mcq Question Set 6
  73. Chemical Engineering Mcq Question Set 7
  74. Chemical Engineering Mcq Question Set 8
  75. Civil Engineering Basic Set 1
  76. Chemical Engineering Mcq Question Set 9
  77. Chemical Engineering Mcq Question Set 10
  78. Civil Engineering Basic Set 2
  79. Chemical Engineering Mcq Question Set 11
  80. Chemical Engineering Mcq Question Set 12
  81. Engineering Electrical Engineering
  82. Chemical Engineering Mcq Question Set 14
  83. Chemical Engineering Mcq Question Set 15
  84. Chemical Engineering Mcq Question Set 16
  85. Chemical Engineering Mcq Question Set 17
  86. Engineering Electronics & Communication Engineering
  87. Engineering Computer Science & Engineering
  88. Computer Science & Engineering Computer Networks Mcq
  89. Environmental Engineering MCQ
  90. Microwave Engineering ECE Mcq
  91. Electrical Engineering Mcq
  92. Engineering Branch Wise MCQs
  93. Software Engineering Multiple Choice Questions
  94. Traffic Engineering MCQ
  95. Highway Engineering MCQs
  96. Engineering Thermodynamics MCQs
  97. Materials and Processes -Notch Toughness
  98. Software Engineering Multiple Choice Question Set 1
  99. Software Engineering Multiple Choice Question Set 2
  100. Software Engineering Multiple Choice Question Set 3
  101. Software Engineering Multiple Choice Question Set 4
Search
R4R Team
R4Rin Top Tutorials are Core Java,Hibernate ,Spring,Sturts.The content on R4R.in website is done by expert team not only with the help of books but along with the strong professional knowledge in all context like coding,designing, marketing,etc!