ELECTRICIAN`S MATE Quiz 08

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1. An exercise in rigging casualty power is not considered completed until damage control central receives the report stating that what action(s) have been completed?

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Cables have been restored and PMS has been accomplished

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All portable cables have been restored only

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The equipment is operating on normal power and all portable cables have been restored

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The equipment is operating on normal power only
The equipment is operating on normal power and all portable cables have been restored
2. To obtain maximum current output from a single-phase transformer, you should connect the sections of the secondary windings in what configuration?

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Parallel-opposing

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Series-opposing

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3. In the formula Eg = Kè N, what does the K represent?

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The synchronous speed of the magnetic field

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The generated voltage

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The strength of the magnetic field

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The constant determined by the construction
The constant determined by the construction
4. When using spliced cables, what action should you take?

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Measure the cables to make sure they aren’t too short

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Remove all spliced connections from shore power cables

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Make sure the phases are continuous and have not been altered at the splice

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Use spliced cables only in low-voltage systems
Make sure the phases are continuous and have not been altered at the splice
5. When, if ever, is it permissible to move energized shore power cables?

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When the ship is being inspected by an admiral and the cable must be arranged neatly

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While fighting a fire on the pier

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While troubleshooting the source of smoke coming from the cables

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Never
Never
6. When a generator is used exclusively for casualty power purposes, you must perform which of the following actions?

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Open the generator circuit breaker

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Strip the switchboard that the generator is feeding

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Transfer all bus transfer switches to emergency power
7. What is the key component of the phase sequence indicator?

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The three-phase Rectox unit in parallel with a fill-wave rectifier

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The digital display

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The saturable reactor

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The three-phase induction motor
The three-phase induction motor
8. What is the (a) normal current carrying capacity of portable casualty power cables and (b) the casualty current-carrying capacity?

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(a) 200 A (b) 200 A

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(a) 93 A (b) 200 A

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(a) 93 A (b) 93 A

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(a) 200 A (b) 93 A
(a) 93 A (b) 200 A
9. When unrigging casualty power, what procedure should you follow?

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Unrig the cable between the power source and the load, and then proceed to the power source and load

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Remove both ends of the last cable at the load, and then proceed step-by-step to the power source

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Remove both ends of the first cable at the power source, and then proceed step-bystep to the load

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Remove both ends of the first cable at the power source, remove both ends of the last cable at the load, and then unrig the remaining cables
Remove both ends of the first cable at the power source, remove both ends of the last cable at the load, and then unrig the remaining cables
10. Which of the following types of equipment are used to supply 400 hertz power to a transformer?

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Motor generator units

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Static converters

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Both 1 and 2 above

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Steam turbines
Both 1 and 2 above
11. The casualty power system provides a good means of testing repaired equipment without jeopardizing the normal electrical distribution system.

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True

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False
True
12. What are the two principal types of transformer construction?

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Core and shell

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Power and current

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Shell and pancake

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Polyphase and single phase
Core and shell
13. What is the main purpose of the casualty power system?

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To make permanent connections to vital equipment

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To make temporary connections to furnish power to ac generators

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To make temporary connections to vital circuits

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To make permanent connections to vital circuits
To make temporary connections to vital circuits
14. What letter is used to identify the secondary winding of a power transformer?

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T

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H

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L
X
15. What person is authorized to order the energization of the casualty power system?

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The E division LCPO

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The E division officer

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The damage control assistant

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The electrical officer
The electrical officer
16. Casualty power bulkhead terminals are permanently installed on opposite sides of the bulkhead for what reason?

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To transmit power through decks without loss of watertight integrity

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To provide casualty power to selected equipment

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To transmit power through compartments without loss of watertight integrity

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To provide a means of making proper phase polarity checks
To transmit power through compartments without loss of watertight integrity
17. When a large number of single-phase loads are supplied from a three-phase transformer bank, what is the desirable connection of the transformer secondary?

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Wye

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High voltage

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Low power factor

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Delta
Wye
18. To what publication should you refer for the insulation resistance requirements for shore power cables?

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NSTM, chapter 300

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OPNAVINST 5100.19

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OPNAVINST 4790.4

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EIMB
NSTM, chapter 300
19. A portable cable used to rig ac casualty power systems can carry (a) what maximum current for (b) what maximum number of hours?

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(a) 200 A (b) 4

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(a) 92 A (b) 40

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(a) 92 A (b) 4

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(a) 200 A (b) 40
(a) 200 A (b) 4
20. It is hazardous for a shore power installation to have one circuit breaker supplying more than one power cable for what reason?

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A fire hazard is created when more than one cable is energized

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Phase rotation and orientation can’t be verified without energizing all the cables at once

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A requirement for handling live cables will exist when unrigging shore power

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The cable may short circuit
Phase rotation and orientation can’t be verified without energizing all the cables at once
21. Which of the following losses does NOT affect the efficiency of a transformer?

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Copper losses

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Leakage reactance losses

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Hysteresis losses

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Eddy current losses
Leakage reactance losses
22. When testing shore power cables, what should be used as the shore ground resistance?

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A 16 AWG or larger wire with one side dropped over the side of the ship

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Phase A of the shore power cable

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The enclosure that houses the shore power terminals or receptacles

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The ship’s hull
The ship’s hull
23. If a transformer is wound with 100 turns on the primary, 150 turns on the secondary, and has a secondary voltage of 600 volts, what voltage is applied to the primary?

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200 V

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600 V

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400 V

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250 V
400 V
24. Shore power connections aboard ship may be used to supply power to another ship alongside.

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True

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False
True
25. By what means are hysteresis losses kept to a minimum in transformers?

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By regulating the temperature of the transformer

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