MECHANIC NEIEP MAIN EXAM 2 (2024/2025) UPDATED VERSION A+ GRADED

MECHANIC NEIEP MAIN EXAM 2 (2024/2025) UPDATED VERSION A+ GRADED 1. Best describe CEMF - ANSWER -Limits current flow 2. What occurs if you pass a conductor through a stationary magnetic field? - ANSWER -The magnet will induce a small voltage into the wire 3. What is the inherent opposition to change in current within an electromagnetic device? - ANSWER -Inductance 4. When a current flow is through a magnetic field, what happens to the magnetic field? - ANSWER -The magnetic field becomes stronger below the connector and weaker above it 5. What is the action in the elementary DC generator of converting AC to DC? - ANSWER -Commutation 6. More coils and commutator segments are added to the elementary DC generator armature in order to do what? - ANSWER -Reduce Ripple 7. What three elements are present when operating a motor or generator? - ANSWER -Magnetic field, current, rotation or movement 8. What does the amount of induced voltage in a wire depend on when moving it through a magnetic field? - ANSWER -Strength of the magnetic field and speed of the wire 9. What oil is used to lubricate a sleeve bearing? - ANSWER -High viscosity oil 10. Describe commutators (3 main things) - ANSWER -Pass current between the brushes and the armature windings, provide switching, and they turn with the armature 11. Define a neutral plane - ANSWER -points in a coil's rotation where zero voltage is induced 12. An electromagnetic field in a generator is created by having current flow in the ____ - ANSWER -Coils wound around the pole piece 13. The frame of a DC machine is ___ - ANSWER -called a yoke, the main support for the machine components, and made of electrical steel 14. The speed of a DC motor depends on armature voltage and ____. - ANSWER -Field Strength 15. What circuit is used for preventing build-up of circulating current when the generator field is de-energized - ANSWER -Suicide 16. What are the two circuits of a separately-excited generator called? - ANSWER -The field and armature circuit 17. How is motor speed changed? - ANSWER -By varying the field or armature voltage 18. What material should you use to seat brushes? - ANSWER -Sandpaper 19. What color is a good commutator with good commutation? - ANSWER -Chocolate 20. Most common cause of commutator problems? - ANSWER -Brush pressure too light 21. What is the result when a brush grades are mixed on a commutator? - ANSWER -The results are unpredictable 22. What is the synchronous speed of a three phase 30Hz 6 pole motor? - ANSWER -600 rpm 23. A squirrel cage motor runs clockwise when connected in ACB phase sequence. What will the motor do when connected in ABC sequence? - ANSWER -The motor will run in the counterclockwise rotation. 24. What device is used to prevent starting wye and delta concurrently - ANSWER -Walking beam 25. What is the percent of slip for a three-phase 60Hz motor that has 6 poles and rotates at 1157RPM? - ANSWER -3.58% 26. Synchronous speed - ANSWER -The speed of the stator's magnetic field on an induction motor 27. AC induction motors... - ANSWER -uses a stator to act as a rotating field 28. A motor that can run on both AC and DC - ANSWER -Universal Motor 29. Polarized electrolytic capacitors - ANSWER -Voltage polarity must be correct 30. What happens in a circuit when the capacitor voltage equals the source voltage? - ANSWER -Current flow stops in the circuit 31. What happens to capacitors the instant when power is applied? - ANSWER -Current is maximum 32. If a circuit has a capacitor of 5 microfarads and a source voltage of 120 volts DC through a resistance of 200K, how long will it take to fully charge? - ANSWER -5 seconds 33. If two capacitors in parallel have equal reactance of 40 ohms, what is the total reactance? - ANSWER -20 ohms 34. What will be the total capacitance if two 125microfarad capacitors are in parallel - ANSWER -250 microfarads 35. What is the unit of inductance? - ANSWER -Henry 36. What effect does CEMF have in an inductive circuit? - ANSWER -It is an opposing force to the applied voltage which resists changes in circuit current 37. At what point is CEMF greatest in an inductive circuit? - ANSWER -When the rate of change for current is maximum 38. In a 100 volt 60Hz circuit, what is the total reactance with a 4 Henry inductor in the circuit? - ANSWER -1507 ohms 39. When using a megger to check insulation resistance to ground, what is an acceptable minimum resistance? - ANSWER -1 M ohm 40. What are the terminal designation of the diode? - ANSWER -Anode and cathode 41. What is the voltage drop across a silicon diode that is forward biased? - ANSWER -0.7 volts 42. What type of rectifier uses four diodes to convert the AC to DC? - ANSWER -Full wave bridge 43. Zener Diodes - ANSWER -Designed to operate in reverse bias mode 44. Varistors - ANSWER -Used to prevent component damage from surges 45. What are the common uses of transistors? - ANSWER -Switching and amplification 46. The base and emmiter must be ___ biased in an NPN transistor. - ANSWER -Forward Biased 47. A .7 V drop from ___-__-___ is an indication of a good junction - ANSWER -base-to-emitter 48. What are the leads called on a silicon controlled rectifier? - ANSWER -Anode, gate, cathode 49. Once triggered, a silicon controlled rectifier stays on until - ANSWER -current flow is interrupted 50. When checking a SCR with an ohmmeter, what must be done to verify proper triggering operation? - ANSWER -Connect the negative lead to the cathode and positive lead to the anode and connect a jumper wire from the gate to the anode and then remove the jumper. 51. A silicone controlled rectifier is an example of a... - ANSWER -Discrete electronic component 52. What is normally done to remove ripple voltage from a full wave rectifier? - ANSWER -Add capacitors and inductors after the rectifier diodes 53. Zener diodes - ANSWER -connected in reverse biased in a circuit 54. Characteristic of a Shunt regulator? - ANSWER -If current through the load increases, current through the zener decreases 56. What is the Base 16 system commonly called? - ANSWER -Hexadecimal 57. What is the binary equivalent of 68? - ANSWER - 58. What is the hexadecimal equivalent of (2) - ANSWER -2F9 59. What inputs are necessary to get a low (0) on the output of the NAND - ANSWER -A high (1) on inputs A and B 60. What term describes the type of voltage arrangement associated with a driver circuit with an output to ground potential when active? - ANSWER -Sink 61. What is proper care and handling of printed circuit boards? - ANSWER -Always remove power when installing or removing boards 62. What type of elevator control passes up hall calls in the down direction and down hall calls in the up direction? - ANSWER -Selective collective control 63. What modification to the two-speed AC drive greatly improve floor accuracy? - ANSWER -VVVF drives 64. What type of diagram provides a picture of the appearance and location of elevator parts? - ANSWER -Field wiring diagram 65. What test instrument is best suited to monitor quickly changing voltages and current? - ANSWER -Analog Meter 66. When using the digital multimeter, what jack is the red lead plugged into for all measurements except current? - ANSWER -Volt/Ohm Jack 67. What is an advantage of a digital meter over an analog meter? - ANSWER -Has automatic range selections 68. What should be done first when reporting on the site of a trouble call? - ANSWER -List the condition of the relays and associated contacts 69. What diagram would you use to troubleshoot a controller problem? - ANSWER -Straight-line wiring diagram 70. What is the primary reason AC relay hum or chatter? - ANSWER -AC cycle reversal 71. How would you describe the contact rating of a magnetic switch? - ANSWER -The maximum voltage and current that can be safely interrupted 72. What kind of relay is commonly used for circuits on solid state equipment? - ANSWER -Reed Relay 73. How are latching relays reset? - ANSWER -Electrically 74. Testing with a multimeter, full line voltage is read directly across the door close relay coil. The coil, however will not pull in. What is likely the problem? - ANSWER -Open Coil 75. What would the data 120 NC 8 printed on the side of a bi-metallic timer represent? - ANSWER -An 8 second timer with normally closed contacts and 120 volts 76. When fully charged, what down capacitor voltage equal? - ANSWER -100% of the source voltage 77. When a diode or resistor is connected in parallel across a coil, how is a short delay time achieved? - ANSWER -The collapsing field 78. What is a walking beam? - ANSWER -A mechanical beam that prevents two opposite electrical functions from occurring simultaneously 79. What is the typical labels for the load side of a 3-phase mainline disconnect switch? - ANSWER -L1,L2,L3 80. An elevator equipment room that is equipped with fire sprinklers would require what type of circuit breaker? - ANSWER -Shunt trip circuit breaker 81. What instrument would you use to check a fuse with power remove from the circuit? - ANSWER -Ohmmeter 82. Which of the rectified power supplies is the most efficient? - ANSWER -Three-phase, Full-Wave 83. A Three-phase, full wave power supply uses how many rectifiers? - ANSWER -6 84. A single-phase, full-wave rectifier with 12-VAC input will produce how much DC voltage? - ANSWER -108VDC 85. A blown AC fuse on a three-phase, full-wave rectifier will cause the DC voltage to ____ - ANSWER -Decrease 86. A regulated power supply that produces an almost pure DC is called a(n) ____ - ANSWER -Exciter 87. Most elevator manufacturers use which type of control system? - ANSWER -Grounded 88. When a hydraulic elevator is held at a floor, what prevents the piston from coming back down? - ANSWER -Check Valve 89. What type of drive uses SCRs to control the hoist motor? - ANSWER -Static Drive 90. The overload that consists of a coil, plunger, and a reservoir of silicon fluid is a ____. - ANSWER -Dashpot overload 91. If the car were running up in response to a 3rd floor call, when would the U relay de-energize? - ANSWER -When the selector switch #3 opens 92. What will be the condition of the latching or PL relays when the car is at the top floor? - ANSWER -All set 93. What is meant by self-holding a call relay? - ANSWER -Holding a relay in with its own contact 94. What method is used to cancel a registered call? - ANSWER -Tapped relay coil with selector cancelling 95. If a car speed were 100FPM, what should the stopping distance be? - ANSWER -24 inches 96. When the car is closer than the proper slowdown distance, which circuit prevents an elevator from getting the stopping signal? - ANSWER -Late call refusal 97. A safety operated switch is considered a ____ - ANSWER -Primary Safety Device 98. What is the time constant for a circuit with 150KOhms and a 2 microfarad capacitor? - ANSWER -.3 seconds 99. What must be done before checking pump drive belts on a hydraulic elevator - ANSWER -Pull the main disconnect switch 100. Which of the following best describes the danger posed be the counterweight assembly when you are riding the car top? - ANSWER -It run close by in the opposite direction 101. Why must you place a hydraulic elevator car on jack posts before servicing the packing head? - ANSWER -Because a hydraulic elevator is supported by a column of oil. 102. Why can't Elevator Constructors use a metal ladder? - ANSWER -Metal ladders conduct electricity 103. What is the function of a Ground Fault Circuit Interrupter? - ANSWER -To detect and imbalance in current between the hot and nuetral wires 104. How do you determine the correct angle from the vertical for placing a ladder - ANSWER -Measure out a distance of 1/4 the height. 105. When using rope wedge sockets... - ANSWER -Use a wedge and socket sized correctly for the rope. 106. If a hoist machine roped 1:1 is capable of running at 650fpm with a capacity of 4500lbs, what would the capability be if roped 2:1? - ANSWER -325 fpm at 9000lbs 107. More torque. Less speed. Double the reeve, double the weight and half the speed. 108. What rope has wires Presh aped to fit the twist in the strands and preshaped to fit the twist in the ropes? - ANSWER -Preformed 109. What is it called when a load is added to a wire rope,it stretches, and when the load is removed, it returns to its original length? - ANSWER -Elastic Stretch 110. What wire rope construction is the most wear resistant? - ANSWER -6 x 19 Seale 111. What is the construction stretch of a 500ft fiber core, 8 strand rope rated at 3/4% (.0075) of rope stretch per hundred foot? - ANSWER -3.75FT 500 x .0075=3.75 112. Which lay of wire rope has the strand wires in line with the rope axis? - ANSWER -Regular Lay 113. At what speed should counterweight safeties be set to trip? - ANSWER -UP TO 10% higher than the car governor 114. What type of safety uses an oil buffer btween the car and safety planks? - ANSWER -Type C 115. If you have a 3500lb car rated at 4000lbs capacity, how much should the counterweight assembly weigh for a normal 40% install? - ANSWER -5100lbs 116. When an occupiable space below the pit, what additional equipment is required on the counterweight? - ANSWER -Safeties 117. What functions can load weighing transducers perform? - ANSWER -Adjust door times, bypass hall calls, and adjust motor control. 118. How high would you block up a counterweight frame before roping that had a counterweight buffer height of 32", rope stretch of 12"; bottom counterweight run by of 18"; and pit depth of 8 feet? - ANSWER -62 inches 119. What document may be the only place to look for information such as the type of fixtures, car panel, fire service floor, etc? - ANSWER -Job abstract 120. Which type of diagram shows the simplified path from positive to negative for all components in a circuit - ANSWER -Straight Line 121. What term best describes typing all metal parts at ground potential to minimize electrical shock hazards? - ANSWER -Bonding 122. When bending conduit, what is the maximum number of degrees of bend allowed between access points? - ANSWER -360 degrees 123. You are working with motor-generators leads. WHat is the maximum length that may be connected directly to the controller without being run inside a raceway? - ANSWER -6 feet 124. What is the regerence point on the thinwall bender for the finish line of a back to back bend? - ANSWER -The start point