# Electricity.txt

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1. Voltage is represented by what letter?
V
2. Charge represented by what letter?
Q
3. The rate of electron flow in an electrical circuit is what?
Current
4. The amount of electron crowding refers to what?
Current density
5. energy is the product of what?
Power and time
6. Define power?
Rate of doing work
7. Passive and active elements of a circuit consume or use what?
Energy
8. What type of circuit is not carrying any current?
Open
9. Large Load circuits require what type of disconnects?
Manual
10. How do alternate action and momentary switches differ?
Momentary switches returned home after release
11. What switches can be used to switch between more than 2 circuits?
Rotary switches
12. What switches are used to detect hydraulic oil levels?
Reed switches
13. What is the positive terminal of a diode known as?
anode
14. What type of bias is it when a diode is connected in the proper polarity as current passes through it?
forward
15. The output of a transistor is known as a what?
Emitter
16. What is an example of a analog IC?
Electronic voltage regulator
17. Digital ics are used in binary processes and what?
Calculations
18. electricity is applied to what of a solenoid?
Coil
19. Linear force of a solenoid is determined by what?
Number of turns in the coil
20. Electricity travels at what speed?
Speed of light
21. When a materials electrons have become aligned and creates a force external to its self it is called a what?
Magnet
22. When a loop of wire is rotated between the poles of a magnet what are made to flow through the wire?
Electrons
23. What allows the generation of pulsing direct current?
Commutator
24. when comparing flow of electricity through a wire to water flowing through a pipe what is similar to the water pressure?
Voltage
25. How many times does AC current reverse its polarity each cycle?
Twice
26. Passing a conductor through magnetic field in generating a current is known as what?
Inducing a current
27. One magnet is made to turn inside of another magnet in a motor by switching what of the turning magnet?
Poles
28. Instead of using a permanent magnet to generate a stationary magnetic field most motors use what?
Field coils
29. What does the stator consist of?
Core and winding inside the motor
30. The magnet that turns inside the motor is called the what?
Rotor
31. A motor that runs on AC or DC is a what kind of motor?
Universal
32. The device used to change the voltage level of alternating current is a what?
Transformer
33. Atoms bind together in a molecule using ________ energy.
chemical
34. ________ is the force developed by a motor and applied to a shaft.
Torque
35. What is the method used to start a DC generator turning?
Primemover
36. What are the three causes of overheating ball bearings?
• overpacked grease
• improper lubrication
• misalignment
37. What is defined as an electrical connection between the wiring of a motor and its metal frame work?
Ground
38. Dust and foreign particles are cleaned from electrical equipment while limiting damage to electrical components by what?
vacuum
39. What type of AC single phase motors will also operate on direct current?
Series wound
40. What is used aboard ships with AC generators to step-up or step-down voltage?
transformers
41. The reversal of an AC, three phase, induction motor is accomplished by what?
42. If the frequency is reduced from 60 to 55 hertz on a 120/240 volt three phase motor, the motor would what?
slow down
43. On a diesel electric plant, raising the field excitation will cause the DC propulsion motor to what?
increase in speed
44. Adding resistance in series with field winding of a DC shunt motor without a load, will cause the motor speed to what?
increase
45. The item referred to as a pigtail on a DC motor brush rigging is a what?
uninsulated wire
46. The electrolyte used in a nickel cadmium battery is distilled water and what?
potassium hydroxide
47. The number of cells in a 12 volt lead acid battery is what?
6
48. What is the electrolyte in a lead acid storage battery?
distilled water and sulfuric acid
49. What is the formula to calculate MMF?
Amps x Number of turns = Ampere turns
50. The opposition to the establishment of magnetic lines of force in a magnetic circuit is the circuits _________.
reluctance
51. All of the conductors in a DC series circuit have the same what?
current
52. The total voltage of a series circuit is the ____________.
sum of individual voltage drops
53. The total power used up in a series circuit is __________.
sum of the powers used
54. What are the components of a fluorescent lighting system?
• lamps
• ballast
• started
55. The source of emergency lighting and power at loss of normal ships power on a cargo vessel should be obtained from the what?
Emergency generator to emergency switch board
56. The voice signal generated by a sound powered phone transmitter is proportional to what?
Amplitude and frequency striking the diaphragm.
57. Main engine room control console alarms are to be of the self monitoring type, meaning that an open circuit to a particular alarm circuit will what?
cause an alarm
58. When the console indicating lamp burns out, attempt to renew it should not be made while maneuvering because why?
it can cause a ground or short of a vital function
59. What has an measurable effect on AC circuits?
Capacitors, inductors, resistors
60. On a DC generator, a rheostat is connected in series with the shunt field to adjust what?
field current
61. An AC generator output is generated in the what?
armature windings
62. Contactors of a magnetic controller are operated by what?
electromechanical devices
63. The current coil of a watt meter or ammeter must be connected how?
64. What minimizes the stroboscopic effect of fluorescent lamps that operate on a 3 phase AC circuit?
Operate lamps at more than one phase
65. What type of bearing are used in large propulsion generators and motors?
journal bearings
66. What is an acceptable resistance reading for the ground connection between the ships hull and the metal frame of a portable drill?
less than 1 ohm
67. What indicates ball bearing malfunction in operating machinery?
high temperatures and loss of speed
68. Dirt, moisture, and oil in generator and motor ventilation ducts cause overheating by?
not allowing heat to dissipate
69. What is the unit for capacitance?
70. When field resistance is increased voltage will what?
decrease
71. What is provided by the exciter on an AC generator?
Direct current to field windings
72. What 3 steps are taken prior to working on a high voltage circuit?
• Remove power
• Discharge capacitors
• ground the circuit
73. Aboard a ship, selective tripping does what?
Isolates faulty circuits
74. AC generator frequency varies directly with what?
rotor speed
75. What type of overload relays requires a time delay before resetting?
thermal
76. What is the preferred method for cleaning motors and generators?
vacuum
77. What is the minimum amount of electric current that can cause fatal shock?
10 milliamps
78. What must occur to reverse propeller rotation in a diesel electric DC propulsion system?
Change polarity of generator terminal voltage
79. What is the basis of electricity?
transfer of electrons
80. What type of charge does an electron carry?
negative
81. What is an example of a variable?
temperature
82. What do coulombs measure?
charge
83. What are the conditions necessary to produce electromotive force in a generator?
conductor capable carrying current moving in a magnetic field
84. What is the phenomena of counter electromotive force?
Generator action in a motor
85. Why do electrical contactors move when energized?
Magnetic lines of flux pull the movable permeable core into the coil
 Author: joshua3731 ID: 207512 Card Set: Electricity.txt Updated: 2013-03-16 16:46:01 Tags: junior eng Folders: Description: russel bravo is gay Show Answers: