industrial drives Mcqs
51. _______________has the least value of starting torque to full load torque ratio?
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A. D.C. shunt motor

B. D.C. series motor

C. Slip ring induction motor

D. Squirrel cage induction motor
52. ___________________is preferred for synthetic fibre mills?
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A. Series motor

B. Synchronous motor

C. Shunt motor

D. Reluctance motor
53. The travelling speed of cranes varies from_________________?
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A. 5 to 10 m/s

B. 1 to 2.5 m/s

C. 10 to 15 m/s

D. 20 to 30 m/s

54. Which part of a motor needs maximum attention for maintenance ?
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A. Rotor winding

B. Rearing

C. Stator winding

D. Frame

55. For derries and winches which of the following drives can be used ?
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A. A.C. slip ring motors with variable resistance

B. Pole changing squirrel cage motors

C. D.C. motors with Ward-leonard con-trol

D. Any of the above
56. In which of the following applications variable speed operation is preferred ?
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A. Exhaust fan

B. Refrigerator

C. Ceiling fan

D. Water pump

57. Heavy duty cranes are used in________________?
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A. all of the above

B. steel plants

C. ore handling plants

D. heavy engineering workshops

58. Battery operated scooter for braking uses__________________?
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A. plugging

B. rheostatic braking

C. regenerative braking

D. mechanical braking
59. For which of the following applications motor has to start with high acceleration ?
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A. Centrifugal pump

B. Oil expeller

C. Lifts and hoists

D. Floor mill

60. Which of the following is essentially needed while selecting a motor ?
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A. Foundation pedal

B. Bearings

C. Pulley

D. Starter
61. Flame proof motors are used in_________________?
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A. steel mills

B. explosive atmospheres

C. moist atmospheres

D. paper mills

62. In jaw crushers a motor has to often start against ____________________ load?
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A. heavy

B. normal

C. low

D. medium

63. Which of the following motors always starts on load ?
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A. Fan motor

B. All of the above

C. Floor mill motor

D. Conveyor motor

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

B. Braking

C. Efficiency

D. Running characteristics

65. The load cycle for a motor driving a power press will be________________?
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A. continuous but periodical

B. variable load

C. intermittent and variable load

D. continuous

66. ________________is preferred for automatic drives?
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A. Ward-Leonard controlled D.C. motors

B. Any of the above

C. Squirrel cage induction motor

D. Synchronous motors

67. Which of the following motors are pre-ferred for overhead travelling cranes ?
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A. Slow speed motors

B. Continuous duty motors

C. Short time rated motors

D. None of the above

68. When the load is above _______________ a synchronous motor is found to be more economical?
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A. 50 kW

B. 20 kW

C. 100 kW

D. 2 kW

69. Light duty cranes are used in which of the following ?
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A. All of the above

B. Pumping stations

C. Power houses

D. Automobile workshops

70. Which of the following motors is preferred for traction work ?
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A. Three-phase induction motor

B. Synchronous motor

C. Universal motor

D. D.C. series motor

71. The selection of an electric motor for any application depends on which of the following factors ?
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A. All of the above

B. Mechanical characteristics

C. Cost

D. Electrical characteristics

E. Size and rating of motors