Industrial Drives Multiple Choice Questions and Answers

In this article, we shared the 70 industrial drives MCQ questions and answers to test your knowledge.

Industrial Drives Questions and Answers

Industrial Drives Multiple Choice Questions and Answers

The below list provides all the multiple-choice questions related to the industrial drives technical subject.

Answers are available at the bottom of the article.

1. The cost of an induction motor will increase as

A)horsepower rating decreases but r.p.m. increases
B)horsepower rating and operating speed decreases
C)horsepower rating increases but r.p.m. decreases
D)horsepower rating and operating speed increases

2. Which of the following motors are preferred for overhead traveling cranes?

A)Slow speed motors
B)None of these answers
C)Continuous duty motors
D)Short time rated motors

3. Which of the following motors is preferred for the boom hoist of a traveling crane?

A)A.G. slip ring motor
B)Single-phase motor
C)Synchronous motor
D)Ward-Leonard controlled D.C. shunt motor

4. Flameproof motors are used in

A)paper mills
B)moist atmospheres
C)explosive atmospheres
D)steel mills

5. A pony motor is used for the starting of which of the following motors?

A)Synchronous motor
B)None of these answers
C)Schrage motor
D)Squirrel cage induction motor

6. ____ has the least range of speed control.

A)Schrage motor
B)Synchronous motor
C)D.C. shunt motor
D)Slip ring induction motor

7. Which of the following motors are best for the rolling mills?

A)Slip ring induction motors
B)D.C. motors
C)Squirrel cage induction motors
D)Single-phase motors

8. Which of the following motors is preferred when smooth and precise speed control over a wide range is desired?

A)Synchronous motor
B)Squirrel cage induction motor
C)D.C. motor
D)Wound rotor induction motor

9. For a motor-generator set which of the following motors will be preferred?

A)Slip ring induction motor,
B)Synchronous motor
C)Pole changing induction motor
D)Squirrel cage induction motor

10. Which feature, while selecting a motor for centrifugal pump, will be of least significance?

A)Speed control
B)Horse power
C)Starting characteristics
D)Operating speed

11. For which of the following applications motor has to start with high acceleration?

A)Lifts and hoists
B)Oil expeller
C)Floor mill
D)Centrifugal pump

12. The starting torque in the case of centrifugal pumps is generally

A)less than running torque
B)slightly more than running torque
C)double the running torque
D)same as running torque

13. Which of the following motors has series characteristics?

A)Capacitor start motor
B)Shaded pole motor
C)None of these answers
D)Repulsion motor

14. Heavy-duty cranes are used in

A)steel plants
B)heavy engineering workshops
C)all of these answers
D)ore handling plants

15. The traveling speed of cranes varies from

A)10 to 15 m/s
B)20 to 30 m/s
C)1 to 2.5 m/s
D)5 to 10 m/s

16. A reluctance motor ____

A)is provided with slip rings
B)is compact
C)requires starting gear
D)has high cost

17. For a particular application the type of electric and control gear are determined by which of the following considerations?

A)Starting torque
B)All of these answers
C)Conditions of environment
D)Limitation on starting current
E)Speed control range and its nature

18. The diameter of the rotor shaft for an electric motor depends on which of the following

A)r.p.m. only
B)Horse power, r.p.m. and power factor
C)Horse power and r.p.m.
D)Horse power only

19. Which part of a motor needs maximum attention for maintenance?

C)Rotor winding
D)Stator winding

20. ____ motor is a constant speed motor.

A)Universal motor
B)Synchronous motor
C)Schrage motor
D)Induction motor

21. In ____ the speed can be varied by changing the position of brushes.

A)schrage motor
B)slip ring motor
C)induction motor
D)repulsion motor

22. ____ has the least value of starting torque to full load torque ratio.

A)Squirrel cage induction motor
B)D.C. shunt motor
C)D.C. series motor
D)Slip ring induction motor

23. In which of the following application the load on the motor change in cyclic order?

B)All of these answers
C)Electric shovels
D)Rolling mills

24. Heat control switches are used in

B)cooling ranges
C)single phase
D)three phase induction motors

25. Rotor of a motor is usually supported on____ bearings.

C)ball or roller

26. Light duty cranes are used in which of the following ?

A)Pumping stations
B)All of these answers
C)Automobile workshops
D)Power houses

27. Reluctance motor is a ____

A)low noise, slow speed motor
B)self starting type synchronous motor
C)low torque variable speed motor
D)variable torque motor

28. Ward-Leonard controlled D.C. drives are generally used for ____ excavators.

A)Light duty
B)All of these answers
C)Medium duty
D)Heavy duty

29. Which of the following motors is preferred when quick speed reversal is the main consideration ?

A)Synchronous motor
B)Wound rotor induction motor
C)Squirrel cage induction motor
D)D.C. motor

30. The selection of an electric motor for any application depends on which of the following factors ?

A)All of these answers
B)Electrical characteristics
C)Mechanical characteristics
D)Size and rating of motors

31. When the load is above____ a synchronous motor is found to be more economical.

A)2 kW
B)20 kW
C)50 kW
D)100 kW

32. ____ is not a part of ball bearing ?

A)Outer race
B)Inner race

33. ____ has relatively wider range of speed control.

A)D.C. shunt motor
B)Synchronous motor
C)Ship ring induction motor
D)Squirrel cage induction motor

34. A wound rotor induction motor is preferred, as compared to squirrel cage induction motor, when major consideration is

A)all of these answers
B)low windage losses
C)slop speed operation
D)high starting torque

35. By the use of which of the following D.C. can be obtained from A.C. ?

A)Mercury arc rectifier
B)Silicon diodes
C)Any of these answers
D)Motor generator set

36. The load cycle for a motor driving a power press will be

B)intermittent and variable load
C)variable load
D)continuous but periodical

37. ____ method of starting a three phase induction motor needs six terminals

B)None of these answers
D)Resistance starting

38. Battery operated scooter for braking uses

A)rheostatic braking
B)mechanical braking
D)regenerative braking

39. Besides a constant speed a synchronous rotor possesses which of the following advantages

A)Better efficiency
B)All of these answers
C)High power factor
D)Lower cost

40. Which of the following alternatives will be cheaper ?

A)100 H.P. A.C. three phase motor
B)Ten motors of 10 H.P. each
C)Four motors of 25 H.P. each
D)Five motors of 20 H.P. each

41. Which of the following machines has heavy fluctuation of load ?

A)Printing machine
C)Punching machine

42. For derries and winches which of the following drives can be used ?

A)Pole changing squirrel cage motors
B)Any of these answers
C)D.C. motors with Ward-leonard control
D)A.C. slip ring motors with variable resistance

43. ____ is preferred for synthetic fibre mills.

A)Series motor
B)Synchronous motor
C)Shunt motor
D)Reluctance motor

44. For crane travel which of the following motors is normally used ?

A)D.C. differentially compound motor
B)A.C. slip ring motor
C)Synchronous motor
D)Ward-Leonard controlled D.C. shunt motor

45. The starting torque of a D.C. motor is independent of which of the following?

C)Armature current
D)Flux and armature current

46. Which of the following happens when star-delta starter is used ?

A)Starting current is reduced
B)Starting voltage is reduced
C)None of these answers
D)Both Starting voltage is reduced and Starting current is reduced

47. In which of the following applications variable speed operation is preferred ?

A)Ceiling fan
C)Exhaust fan
D)Water pump

48. In ____ method of starting three-phase induction motors the starting voltage is not reduced.

B)any of these answers
D)slip ring

49. In squirrel cage induction motors which of the following methods of starting cannot be used ?

A)Resistance in stator circuit
B)Star Delta Starting
C)Resistance in rotor circuit
D)Auto-transformer starting

50. Which of the following types of the motor enclosure is safest?

A)Open type
B)Totally enclosed fan cooled
C)Semi closed
D)Totally enclosed

51. Which of the following motors is usually preferred for kiln drives?

A)Cascade controlled A.C. motor
B)Three phase shunt wound commutator motor
C)Any of these answers
D)Slip ring induction motor

52. Which of the following motors always starts on load?

A)Floor mill motor
B)Conveyor motor
C)All of these answers
D)Fan motor

53. While selecting motor for an air conditioner which of the following characteristics is of great importance?

A)Arrangement for power transmission
B)Type of enclosure
C)Type of bearings
D)None of these answers

54. The capacity of a crane is expressed in terms of

A)type of drive
B)any of these answers

55. While selecting an electric motor for a floor mill, which electrical characteristics will be of least significance?

A)Running characteristics
C)Starting characteristics

56. In a series motor which of the following methods can be used for changing the flux per pole?

A)Tapped field control
B)Series-parallel control
C)Diverter field control
D)Any of these answers

57. Which of the following is essentially needed while selecting a motor?

A)Foundation pedal

58. Which of the following motors is preferred for traction work?

A)Three-phase induction motor
B)Universal motor
C)Synchronous motor
D)D.C. series motor

59. For a D.C. shunt motor which of the following is incorrect?

A)Unsuitable for heavy-duty starting
B)Torque-armature current is a straight line
C)Torque is zero for zero armature current
D)Torque varies as armature current

60. For which of the following applications ‘D.C. motors are still preferred?

A)Variable speed drive
B)High starting torque
C)High-efficiency operation

61. For blowers which of the following motors is preferred?

A)D.C. shunt motor
B)Wound rotor induction motor
C)D.C. series motor
D)Squirrel cage induction motor

62. In jaw crushers a motor has to often start against ____ load.


63. ____ is preferred for automatic drives.

A)Any of these answers
B)Ward-Leonard controlled D.C. motors
C)Squirrel cage induction motor
D)Synchronous motors

64. The characteristics of drive for crane hoisting and lowering are which of the following?

A)Precise control
B)All of these answers
C)Smooth movement
D)Fast speed control

65. Which of the following motors is used for elevators?

A)Any of these answers
B)Capacitor start single phase motor
C)Synchronous motor
D)Induction motor

66. ____ need frequent starting and stopping of electric motors.

A)Grinding mills
B)Lifts and hoists
C)Paper mills

67. The size of an excavator is usually expressed in terms of

A)crowd motion
B)travel in metres
C)angle of swing
D)cubic metres

68. In the case of ____ speed control by injecting e.m.f. in the rotor circuit is possible.

A)d.c. shunt motor
B)slip ring induction motor
C)schrage motor
D)synchronous motor

69. In a paper mill where constant speed is required

A)synchronous motors are preferred
B)individual drive is preferred
C)A.C. motors are preferred
D)group drive is preferred

70. Belted slip ring induction motor is almost invariably used for

A)none of these answers
B)centrifugal blowers
C)water pumps
D)jaw crushers

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