In this article, we shared the 70 industrial drives MCQ questions and answers to test your knowledge.
Industrial Drives 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?
| A) | Frame |
| B) | Bearing |
| 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?
| A) | Cranes |
| B) | All of these answers |
| C) | Electric shovels |
| D) | Rolling mills |
24. Heat control switches are used in
| A) | transformers |
| B) | cooling ranges |
| C) | single phase |
| D) | three phase induction motors |
25. Rotor of a motor is usually supported on____ bearings.
| A) | bush |
| B) | needle |
| C) | ball or roller |
| D) | thrust |
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 |
| E) | Cost |
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 |
| C) | Cage |
| D) | Bush |
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
| A) | continuous |
| B) | intermittent and variable load |
| C) | variable load |
| D) | continuous but periodical |
37. ____ method of starting a three phase induction motor needs six terminals
| A) | Auto-transformer |
| B) | None of these answers |
| C) | Star-delta |
| D) | Resistance starting |
38. Battery operated scooter for braking uses
| A) | rheostatic braking |
| B) | mechanical braking |
| C) | plugging |
| 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 |
| B) | Planer |
| C) | Punching machine |
| D) | Lathe |
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?
| A) | Flux |
| B) | Speed |
| 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 |
| B) | Refrigerator |
| C) | Exhaust fan |
| D) | Water pump |
48. In ____ method of starting three-phase induction motors the starting voltage is not reduced.
| A) | star-delta |
| B) | any of these answers |
| C) | auto-transformer |
| 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 |
| E) | Noise |
54. The capacity of a crane is expressed in terms of
| A) | type of drive |
| B) | any of these answers |
| C) | span |
| D) | tonnes |
55. While selecting an electric motor for a floor mill, which electrical characteristics will be of least significance?
| A) | Running characteristics |
| B) | Braking |
| C) | Starting characteristics |
| D) | Efficiency |
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 |
| B) | Pulley |
| C) | Bearings |
| D) | Starter |
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 |
| D) | Reversibility |
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.
| A) | medium |
| B) | heavy |
| C) | low |
| D) | normal |
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 |
| D) | Air-conditioners |
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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