Motors & Controls MCQ
1. Fitts' law states that __________ is linearly related to index of difficulty (id).
Answer
Correct Answer:
Movement time
Note: This Question is unanswered, help us to find answer for this one
2. What is J?
Answer
Correct Answer:
Per unit moment of inertia
Note: This Question is unanswered, help us to find answer for this one
3. What does J represent in the per unit moment of inertia?
Answer
Correct Answer:
Time in seconds to accelerate the motor armature to rated base speed
Note: This Question is unanswered, help us to find answer for this one
4. What is the name of the system that uses five specialized elements to insulate a motor?
Answer
Correct Answer:
Insulation System
Note: This Question is unanswered, help us to find answer for this one
5. What is the unit of Inertia?
Answer
Correct Answer:
Lb.-ft.2 or oz.-in.2
Note: This Question is unanswered, help us to find answer for this one
6. In an induction motor, what is the primary winding connected to?
Answer
Correct Answer:
The power source
Note: This Question is unanswered, help us to find answer for this one
7. In an induction motor, there is no physical electrical connection to the _____.
Answer
Correct Answer:
Secondary winding
Note: This Question is unanswered, help us to find answer for this one
8. What produces a varying magnetic field?
Answer
Correct Answer:
Varying current
Note: This Question is unanswered, help us to find answer for this one
9. What is HYSTERESIS LOSS?
Answer
Correct Answer:
The resistance offered by materials to becoming magnetized.
Note: This Question is unanswered, help us to find answer for this one
10. What is the meaning of HERTZ?
Answer
Correct Answer:
One cycle per second
Note: This Question is unanswered, help us to find answer for this one
11. What is the purpose of a heat exchanger?
Answer
Correct Answer:
To transfer the heat from inside the motor to another medium
Note: This Question is unanswered, help us to find answer for this one
12. What is the purpose of having a guarded motor?
Answer
Correct Answer:
To prevent accidental contact with live or rotating parts
Note: This Question is unanswered, help us to find answer for this one
13. What is a grounded motor?
Answer
Correct Answer:
A motor with an electrical connection between the motor frame and ground.
Note: This Question is unanswered, help us to find answer for this one
14. What is the NEMA design of a general-purpose motor?
Note: This Question is unanswered, help us to find answer for this one
15. What does NEMA stand for?
Answer
Correct Answer:
National Electrical Manufacturers Association
Note: This Question is unanswered, help us to find answer for this one
16. What is GEARMOTOR?
Answer
Correct Answer:
A gearhead and motor combination to reduce the speed of the motor to obtain the desired speed or torque.
Note: This Question is unanswered, help us to find answer for this one
17. What does a gearhead do?
Answer
Correct Answer:
Converts the basic motor speed to the rated output speed.
Note: This Question is unanswered, help us to find answer for this one
18. What does the frame of an AC motor support?
Answer
Correct Answer:
The stator parts
Note: This Question is unanswered, help us to find answer for this one
19. What is the range of rpm for a FHP motor?
Answer
Correct Answer:
1700-1800 rpm
Note: This Question is unanswered, help us to find answer for this one
20. What is the usual RPM of a FHP motor?
Answer
Correct Answer:
1700-1800
Note: This Question is unanswered, help us to find answer for this one
21. What is the advantage of form winding over random (mush) winding?
Answer
Correct Answer:
Form winding allows for better insulation on high voltage than does random (mush) winding.
Note: This Question is unanswered, help us to find answer for this one
22. What is FORM FACTOR?
Answer
Correct Answer:
A figure of merit which indicates how much rectified current departs from pure (non-pulsating) DC.
Note: This Question is unanswered, help us to find answer for this one
23. What is the magnetic field called that is established around an energized conductor or permanent magnet?
Note: This Question is unanswered, help us to find answer for this one
24. What is flux?
Answer
Correct Answer:
The magnetic field which is established around an energized conductor or permanent magnet.
Note: This Question is unanswered, help us to find answer for this one
25. What is the main purpose of FLANGE Mounting?
Answer
Correct Answer:
For mounting equipment to the motor
Note: This Question is unanswered, help us to find answer for this one
26. What is the main purpose of field weakening?
Answer
Correct Answer:
To increase the motor speed
Note: This Question is unanswered, help us to find answer for this one
27. Why is resistance introduced in series with the shunt wound field of the DC motor?
Answer
Correct Answer:
To reduce voltage and current, thereby increasing motor speed.
Note: This Question is unanswered, help us to find answer for this one
28. What does the term "field" refer to in a DC motor?
Answer
Correct Answer:
The stationary (stator) member
Note: This Question is unanswered, help us to find answer for this one
29. Which of the following is NOT true about an explosion-proof enclosure?
Answer
Correct Answer:
The enclosure is not totally enclosed.
Note: This Question is unanswered, help us to find answer for this one
30. What is the primary purpose of an endshield?
Answer
Correct Answer:
To support the bearing and act as a protective guard to the electrical and rotating parts inside the motor.
Note: This Question is unanswered, help us to find answer for this one
31. What are eddy currents?
Answer
Correct Answer:
Localized currents induced in an iron core by alternating magnetic flux
Note: This Question is unanswered, help us to find answer for this one
32. What is the name given to a motor which has its winding structure completely coated with an insulating resin?
Answer
Correct Answer:
Encapsulated winding
Note: This Question is unanswered, help us to find answer for this one
33. What does EMF stand for?
Answer
Correct Answer:
Electromotive force
Note: This Question is unanswered, help us to find answer for this one
34. What is electrical unbalance?
Answer
Correct Answer:
When the voltages of the three different phases are not exactly the same
Note: This Question is unanswered, help us to find answer for this one
35. What is the ratio of electrical inductance to armature resistance?
Answer
Correct Answer:
The electrical time constant
Note: This Question is unanswered, help us to find answer for this one
36. What is the electrical time constant?
Answer
Correct Answer:
The ratio of electrical inductance to armature resistance.
Note: This Question is unanswered, help us to find answer for this one
37. How many electrical degrees are in one complete cycle?
Note: This Question is unanswered, help us to find answer for this one
38. What is the minimum efficiency number for a motor with a nominal efficiency of 54.5%?
Note: This Question is unanswered, help us to find answer for this one
39. Which of the following is not a NEMA code?
Note: This Question is unanswered, help us to find answer for this one
40. Which is the most common NEMA design for AC motors?
Note: This Question is unanswered, help us to find answer for this one
41. What is a Dynamometer used for?
Answer
Correct Answer:
To measure the output torque and speed of a motor
Note: This Question is unanswered, help us to find answer for this one
42. What is the relationship between the operating and rest times called?
Answer
Correct Answer:
Duty cycle
Note: This Question is unanswered, help us to find answer for this one
43. What are the voltages that some motors can operate on?
Answer
Correct Answer:
Multiples of two or the √3 of one another
Note: This Question is unanswered, help us to find answer for this one
44. What is the meaning of DEFINITE PURPOSE MOTOR?
Answer
Correct Answer:
A motor designed for use under special service conditions or for a particular type of application.
Note: This Question is unanswered, help us to find answer for this one
45. What is a DC motor?
Answer
Correct Answer:
A motor using either generated or rectified DC power
Note: This Question is unanswered, help us to find answer for this one
46. Which of the following is not a type of Direct Current?
Answer
Correct Answer:
Continuous
Note: This Question is unanswered, help us to find answer for this one
47. What does DC stand for?
Answer
Correct Answer:
DIRECT CURRENT
Note: This Question is unanswered, help us to find answer for this one
48. What is the "D" flange used for?
Answer
Correct Answer:
Mounting the motor to gear boxes or bulkheads
Note: This Question is unanswered, help us to find answer for this one
49. What is the purpose of a D flange?
Answer
Correct Answer:
For mounting the motor to gear boxes or bulkheads
Note: This Question is unanswered, help us to find answer for this one
50. What is thepurpose of a commutator in an electric motor?
Answer
Correct Answer:
The commutator supplies current to the armature coils
Note: This Question is unanswered, help us to find answer for this one
51. There are three types of capacitor motors. What is the third type?
Answer
Correct Answer:
Capacitor Run
Note: This Question is unanswered, help us to find answer for this one
52. What is the function of COIL in an electric motor?
Answer
Correct Answer:
To carry and produce the magnetic field
Note: This Question is unanswered, help us to find answer for this one
53. What is the function of the COIL in an electric motor?
Answer
Correct Answer:
Carries and produces the magnetic field
Note: This Question is unanswered, help us to find answer for this one
54. What is the name of the device which causes the current to lead the voltage in time phase?
Answer
Correct Answer:
A capacitor
Note: This Question is unanswered, help us to find answer for this one
55. What is the peak of the current wave reached ahead of the voltage wave in an alternating-current circuit?
Answer
Correct Answer:
Capacitor
Note: This Question is unanswered, help us to find answer for this one
56. What is cogging?
Answer
Correct Answer:
Rotation occurring in jerks or increments rather than smooth motion.
Note: This Question is unanswered, help us to find answer for this one
57. What is the canopy?
Answer
Correct Answer:
A protective cover that protects the motor from liquids or solids
Note: This Question is unanswered, help us to find answer for this one
58. What is the function of a canopy on a motor?
Answer
Correct Answer:
To protect it from liquids or solids that might drop onto the motor
Note: This Question is unanswered, help us to find answer for this one
59. What is the definition of cogging?
Answer
Correct Answer:
Rotation occurring in jerks or increments rather than smooth motion.
Note: This Question is unanswered, help us to find answer for this one
60. What is the "C" flange used for?
Answer
Correct Answer:
To mount close-coupled pumps and speed reducers
Note: This Question is unanswered, help us to find answer for this one
61. Which of the following is true about "C" Flange?
Answer
Correct Answer:
The "C" flange is a NEMA standard design.
Note: This Question is unanswered, help us to find answer for this one
62. What does the Canadian Standards Association do?
Answer
Correct Answer:
Produces standards for products used in Canada
Note: This Question is unanswered, help us to find answer for this one
63. What is a clutch?
Answer
Correct Answer:
A mechanical device for engaging and disengaging a motor.
Note: This Question is unanswered, help us to find answer for this one
64. What is a centrifugal cutout switch?
Answer
Correct Answer:
A centrifugally operated automatic mechanism used in conjunction with split phase and other types of single-phase induction motors.
Note: This Question is unanswered, help us to find answer for this one
65. What is CIV?
Answer
Correct Answer:
Corona Inception Voltage
Note: This Question is unanswered, help us to find answer for this one
66. What is the minimum voltage amount that begins the process of ionization of motor windings?
Note: This Question is unanswered, help us to find answer for this one
67. What does CE stand for?
Answer
Correct Answer:
European Standards
Note: This Question is unanswered, help us to find answer for this one
68. What does the CE designation show for a product?
Answer
Correct Answer:
That it meets European Standards for safety and environmental protection.
Note: This Question is unanswered, help us to find answer for this one
69. What is the main difference between the capacitor start single-phase motor and the split phase start motor?
Answer
Correct Answer:
The capacitor start single-phase motor has a capacitor in series with the starting winding.
Note: This Question is unanswered, help us to find answer for this one
70. What does the capacitor do in a capacitor start motor?
Answer
Correct Answer:
Provide better phase relation
Note: This Question is unanswered, help us to find answer for this one
71. What is the torque required to bring a motor down to a standstill called?
Answer
Correct Answer:
Breaking torque
Note: This Question is unanswered, help us to find answer for this one
72. What is the purpose of a brush in a commutated motor?
Answer
Correct Answer:
Conduct current from the power supply to the armature windings
Note: This Question is unanswered, help us to find answer for this one
73. What is the maximum torque a motor will develop at rated voltage without a relatively abrupt drop or loss in speed?
Answer
Correct Answer:
Breakdown torque
Note: This Question is unanswered, help us to find answer for this one
74. What is the definition of BREAKDOWN TORQUE?
Answer
Correct Answer:
The maximum torque a motor will develop at rated voltage without a relatively abrupt drop or loss in speed.
Note: This Question is unanswered, help us to find answer for this one
75. What is the braking torque?
Answer
Correct Answer:
The torque required to bring a motor down to a standstill.
Note: This Question is unanswered, help us to find answer for this one
76. What is the purpose of brakes?
Answer
Correct Answer:
To bring a running motor to a standstill and/or hold a load.
Note: This Question is unanswered, help us to find answer for this one
77. BEARING LIFE rating is the life in hours or revolutions in which:
Answer
Correct Answer:
90% of the bearings selected will obtain or exceed.
Note: This Question is unanswered, help us to find answer for this one
78. What is the main purpose of Bearings?
Answer
Correct Answer:
Reduce friction and wear while supporting rotating elements
Note: This Question is unanswered, help us to find answer for this one
79. What are bearings used for?
Answer
Correct Answer:
To reduce friction and wear while supporting rotating elements
Note: This Question is unanswered, help us to find answer for this one
80. What does BASE SPEED, RPM stand for?
Answer
Correct Answer:
Base Speed, Revolutions per Minute
Note: This Question is unanswered, help us to find answer for this one
81. What is the back end of a motor also called?
Answer
Correct Answer:
The end that carries the coupling or driving pulley
Note: This Question is unanswered, help us to find answer for this one
82. What is the back end of a motor?
Answer
Correct Answer:
The back end of a motor is the end that carries the coupling or driving pulley.
Note: This Question is unanswered, help us to find answer for this one
83. What does ARMATURE CURRENT mean?
Answer
Correct Answer:
Full load armature circuit current.
Note: This Question is unanswered, help us to find answer for this one
84. What is the purpose of an armature in a DC or universal motor?
Answer
Correct Answer:
The armature rotates and creates magnetic flux
Note: This Question is unanswered, help us to find answer for this one
85. What does the term "Armature" refer to in the context of a DC or universal motor?
Answer
Correct Answer:
The portion of the magnetic structure which rotates.
Note: This Question is unanswered, help us to find answer for this one
86. What is an anti-friction bearing?
Answer
Correct Answer:
A bearing utilizing rolling elements between the stationary and rotating assemblies
Note: This Question is unanswered, help us to find answer for this one
87. What is the standard NEMA rating for ambient temperature?
Answer
Correct Answer:
Not to exceed 40 degrees C
Note: This Question is unanswered, help us to find answer for this one
88. What is the maximum altitude at which a NEMA standard motor can operate?
Answer
Correct Answer:
1,000 meters (3,300 feet)
Note: This Question is unanswered, help us to find answer for this one
89. What does an air temperature switch do?
Answer
Correct Answer:
It detects the temperature of the exhausted air
Note: This Question is unanswered, help us to find answer for this one
90. What does an air pressure switch do?
Answer
Correct Answer:
Detects a clogged filter
Note: This Question is unanswered, help us to find answer for this one
91. How is the amount of steel in a motor's stator and rotor increased or decreased?
Answer
Correct Answer:
By lengthening or shortening the rotor and stator
Note: This Question is unanswered, help us to find answer for this one
92. How is the amount of active iron in a motor usually increased or decreased?
Answer
Correct Answer:
By lengthening or shortening the rotor and stator.
Note: This Question is unanswered, help us to find answer for this one
93. What is the force or load that is applied to the motor shaft in a direction parallel to the axis of the shaft called?
Answer
Correct Answer:
Axial thrust
Note: This Question is unanswered, help us to find answer for this one
94. What does ARMATURE RESISTANCE mean?
Answer
Correct Answer:
The resistance of the armature winding of a DC machine.
Note: This Question is unanswered, help us to find answer for this one
95. What is armature resistance measured in?
Note: This Question is unanswered, help us to find answer for this one
96. What is the name of the effect that reduces the torque capacity of a DC motor?
Answer
Correct Answer:
Armature Reaction
Note: This Question is unanswered, help us to find answer for this one
97. What is armature resistance?
Answer
Correct Answer:
The measure of armature resistance in ohms at 25 degrees C (cold)
Note: This Question is unanswered, help us to find answer for this one
98. What is the unit of measurement for armature resistance?
Note: This Question is unanswered, help us to find answer for this one
99. What is the name of the current that flows in the armature winding of a DC motor?
Answer
Correct Answer:
Armature current
Note: This Question is unanswered, help us to find answer for this one
100. What does ARMATURE INDUCTANCE, MH refer to?
Answer
Correct Answer:
Armature inductance in milli-henries (saturated)
Note: This Question is unanswered, help us to find answer for this one
101. What does ARMATURE INDUCTANCE, MH stand for?
Answer
Correct Answer:
Armature inductance in milli-henries (saturated).
Note: This Question is unanswered, help us to find answer for this one
102. What is an AC Motor?
Answer
Correct Answer:
A motor operating on AC current that flows in either direction
Note: This Question is unanswered, help us to find answer for this one
103. How many times does AC current change its direction per second?
Note: This Question is unanswered, help us to find answer for this one
104. How many times does AC current change its direction of flow in a day?
Answer
Correct Answer:
It cycles
Note: This Question is unanswered, help us to find answer for this one
Applied Engineering MCQs | Topic-wise