IMM 2021 - Electric Motor Control

1. State four factors that determine the severity of an electric shock.
2. Explain the three approach boundaries as identified by NFPA 70E®.
3. State three ways to help prevent an unwanted electrostatic discharge (ESD) from damaging equipment.
4. Identify the meanings of the different colors used with safety labels.
5. List the basic electric motor safety rules.
6. State where and when a lockout/tagout device should be used.
7. Describe the different types of lockout devices.
8. State the purpose of applying NFPA 70E® standards.
9. Describe the types of personal protective equipment (PPE).
10. Define arc flash and arc blast and how to minimize their effects.
11. List the different types of head, eye, and ear protection.
12. State the different parts of hand protection used to prevent an electric shock and the purpose of each part.
13. List the different types of foot, back and knee protection.
14. State the purpose of National Electrical Code® (NEC®) and the Article that covers the requirements for motors.
15. State the purpose of grounding.
16. Explain how a ground fault circuit interrupter (GFCI) protects individuals.
17. State the different classes of fires, specifically the electrical fire classification.
18. State the possible materials that create a hazardous location and how hazardous locations are identified.
19. Define confined space and state several ways to help prevent an accident in a confined space.
20. Explain the importance of safety when working on overhead power lines.
21. Describe the different parts of pushbuttons and their functions.
22. Identify the NEMA and IEC enclosure location rating for each service location environmental condition.
23. Identify two-position and three-position selector switches.
24. Explain switch operation given a switch’s truth table.
25. Define joysticks and describe their most common positions.
26. Explain the purpose of a limit switch.
27. Define actuator and describe its typical applications.
28. Explain the importance of properly installing limit switches.
29. Explain the purpose of a foot switch.
30. Identify and draw the symbols for normally open (NO) and normally closed (NC) pressure switches.
31. Identify the different types of pressure switch sensing devices and how they work.
32. Define deadband (differential) as applied to pressure and temperature switches.
33. Explain the advantage and disadvantage of different deadband range settings.
34. Explain the purpose of a temperature switch.
35. Explain the purpose of a flow switch.
36. Explain the purpose of a level switch.
37. Explain the difference between charging and discharging level control circuits.
38. Explain the difference between one- and two- level control circuits.
39. Explain how mechanical contacts can be protected for longer operating life when switching higher currents.
40. Explain how mechanical contacts can be protected for longer operating life when releasing higher pressure.
41. State the procedure for testing mechanical switch contacts using a DMM in an operation al circuit.
42. Explain why knife switches were discontinued as a means of controlling motors and how they were improved.
43. Define manual contactor and explain why one should not be used as a motor starter.
44. Describe double-break contacts and explain how they are used. 
45. Describe how to draw a wiring diagram for manual contactors.
46. Explain the difference between a manual starter and a manual contactor.
47. Explain the difference between how a fuse or circuit breaker protects a circuit and how overload relays protect running motors.
48. Explain how overload heater coils operate to automatically turn off an overloaded motor.
49. Describe how to select the proper AC manual starter.
50. Describe magnetic contactors and explain how they are used.
51. Explain how to design a two-wire control circuit that can be used to control a magnetic contactor.
52. Explain how to design a three-wire control circuit that can be used to control a magnetic contactor.
53. Explain why opening a DC circuit causes more of an arc contact problem than when opening an AC circuit.
54. Define arc chute and explain its usage.
55. Explain how DC magnetic blowout coils work.
56. Explain how to choose a magnetic contactor.
57. Define magnetic motor starter and describe their different means of overload protection.
58. Describe the characteristics that must be considered when selecting an overload heater.
59. Explain how to select the correct overload heater for a given motor using a manufacturer selection chart.
60. Define inherent motor protector and describe the different types.
61. Explain how to troubleshoot circuit breakers.
62. Explain what devices may be added to basic contactors or magnetic motor starters.
63. State the procedure for troubleshooting a motor starter.
64. State the basic rules that determine how and where two or more loads are connected into a control circuit.
65. State the basic rules that determine how and where two or more switches are connected into a control circuit.
66. Add line number references to any given control circuit drawn in line (ladder) diagram format.
67. Add a numerical cross-reference system to any given control circuit drawn in line (ladder) diagram format.
68. Add wire reference numbers to any given control circuit drawn in line (ladder) diagram format.
69. Explain how to add manufacturer’s terminal numbers to any given control circuit drawn in line (ladder) diagram format.
70. Identify the components in an electrical circuit as being a part of the signal, decision, or action section of a control circuit.
71. Define and give an example of switches connected for AND circuit control logic.
72. Define and give an example of switches connected for OR circuit control logic.
73. Define and give an example of how a switch is connected for NOT circuit control logic.
74. Define and give an example of switches connected for NOR circuit control logic.
75. Define and give an example of switches connected for NAND circuit control logic.
76. Define and give an example of switches connected to develop memory control logic.
77. List the four most common gates used in digital electronics. 
78. Identify the input and output pin numbers of digital logic gates within a digital integrated circuit (IC) chip.
79. Draw a control circuit showing how additional stop switches can be connected into a control circuit.
80. Draw a control circuit showing how additional start switches can be connected into a control circuit.
81. Draw a control circuit showing how two motors can be started almost simultaneously.
82. Draw a control circuit showing how a pilot light is used with a pressure switch to indicate device activation and how a pilot is used with a start/stop station to indicate device activation.
83. Draw a control circuit showing how a selector switch is used to provide a common industrial jog/run circuit.
84. Troubleshoot a control circuit using a digital multimeter (DMM) to determine problems with the switches and/or loads of the circuit.
85. Describe a manual starter and explain how a mechanical interlock works.
86. Explain how to reverse three-phase (3ᶲ) motors using manual starters.
87. Explain how to reverse single-phase (1ᶲ) motors using manual starters.
88. Explain how to reverse DC motors using manual starters.
89. Define drum switch and explain how they are used to reverse motors.
90. Explain the difference between a magnetic reversing starter and a manual reversing starter.
91. Explain how auxiliary contact interlocking works.
92. Explain how pushbutton interlocking works.
93. Describe a power circuit and a control circuit.
94. Explain how the circuit for starting and stopping in forward and reverse with indicator lights works.
95. Explain how the circuit for starting and stopping in forward and reverse with limit switches controlling reversing works.
96. Explain how the circuit for starting and stopping in forward and reverse with limit witches as safety stops works.
97. Explain how the circuit for a selector switch used to determine direction of motor travel works.
98. Explain how the circuit for starting, stopping, and jogging in forward and reverse with jogging controlled through a selector switch works.
99. Explain direct hardwiring.
100. Describe hardwiring using terminal strips.
101. Explain how to troubleshoot a power circuit.
102. Explain how to troubleshoot a control circuit.
103. Describe friction brakes.
104. Define and describe plugging.
105. Define and describe electric braking.
106. Define and describe dynamic braking.
107. Explain why a reduced-voltage starting method may be used instead of full-voltage starting.
108. Explain how a reduced-voltage starting method reduces the amount of voltage and current to a DC motor during starting.
109. Explain why reduced-voltage starting is used for three phase (3ᶲ) induction motors.
110. Define primary resistor starting and explain how it reduces the amount of voltage and current to an AC motor during starting.
111. Explain how an autotransformer reduced-voltage starting method reduces the amount of voltage and current to an AC motor during starting.
112. Define part-winding starting and explain how it reduces the amount of voltage and current to an AC motor during starting.
113. Explain how a wye-delta reduced-voltage starting method reduces the amount of voltage and current to an AC motor during starting.
114. Describe the considerations for selecting a starting method and describe the advantages and disadvantages of each.
115. Explain how to troubleshoot a reduced-voltage starting circuit.
116. Describe the differences between how a dashpot timer, a synchronous clock timer, a solid-state, and a solid-state programmable timer produce a time delay.
117. Describe how an on-delay timer operates and give an example of its usage.
118. Describe how an off-delay timer operates and give an example of its usage.
119. Explain how plugging can be accomplished by using timing relays.
120. Describe how a one-shot timer operates and give an example of its usage.
121. Describe multiple function timers.
122. Describe multiple-contact timer wiring diagrams.
123. Give an example of the usage of a multiple-contact timer.
124. Explain the difference between supply voltage-controlled timers, contact-controlled timers, and sensor-controlled timers.
125. Explain how to troubleshoot timing circuits.
126. Describe transistor-controlled timers.
127. Describe 555 and 556 timers.
128. Describe solid-state programmable timers.
129. Describe programmable timers.
130. Define totalizer and counter.
131. Describe up counters and up/down counters.