ET VOL 8 CH 1,3 Flashcards Preview

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Flashcards in ET VOL 8 CH 1,3 Deck (91):
1

2

Three of the four methods of cooling are forced-air, air-to-air, air-to-liquid. What is the fourth?

convection

3

When utilizing forced-air cooling, an air filter must be provided at the air outlet to remove dust and dirt from the exhaust air.

false

4

Heat is removed from the air passing by the heat producing source in an air-to-air cooling system by forcing it through what component?

3. Heat exchanger

5

Efficiency is increased in an airto- liquid cooling system by the use of what system component?

1. Liquid heat exchangers

6

What number of basic cooling systems make up a typical liquid cooling system?

2

7

The secondary cooling system transfers the heat load from the electronic equipment to the primary system.

true

8

The Navy uses what number of basic configurations of liquid cooling systems?

3

9

Which of the following water resources is/are used for primary cooling?

Seawater and chilled water

10

The cooling water for the primary cooling system is either seawater or chilled water. The seawater is from the sea and the chilled water is from what source?

The ship’s air conditioning plant

11

When temperature range is considered to be critical, what type of cooling system would most likely satisfy this need?

Type III (cw/dw heat exchanger with a cw/dw heat exchanger standby)

12

What type of liquid cooling system can satisfactorily be operated when seawater temperatures reach 95°F?

TYpe I (sw/dw heat exchanger with sw/dw heat exchanger standby

13

What is Type II Liquid cooling config?

SW/DW heat exchanger with CW/DW heat exchanger stby

14

In a primary cooling system, flow regulator may be known by what other term?

4. Orifice plate

15

Open looped seawater systems are also called one-pass because the seawater flows through the system only once.

true

16

Secondary cooling systems are which of the following types?

Closed-loop only

17

An expansion tank is installed in what system to compensate for changes in coolant volume?

3. The distilled water

18

What term best describes a expansion tank that is located above the highest point in the secondary system and vented to the atmosphere

4. Gravity tank

19

What term best describes an expansion tank that requires an air charge on the tank and is located below the highest point in the secondary cooling system?

Compression tank

20

What definition best describes the word submicron?

Less than one millionth of a meter

21

The Type II cooling system employs what configuration?

One SW/DW heat exchanger and one standby CW/DW heat exchanger

22

The Type III cooling system employs what configuration?

One CW/DW heat exchanger and one standby CW/DW heat exchanger

23

In a Type III cooling system, the two-way temperature regulating valve is used instead of a threeway valve to regulate the temperature in what system component(s)?

2. The secondary loop

24

Heat exchanger

is constructed to be shell-type and tube-type in which the secondary coolant flows through the shell, while the primary coolant flows through the tubes.

25

Flow regulators

It is used to provide a constant flow of coolant through the system

26

Expansion tank

It maintains a positive pressure on the circulating pump inlet, compensates for changes in the coolant volume and it vents air from the system.

27

Seawater strainer

It is used in the seawater cooling system to remove debris and sea life, which could clog the pressure and flow control devices.

28

Temperature regulating valve

It regulates the amount of cooling water flowing through or bypassing a heat exchanger to maintain a desired temperature of distilled water going to the electronic equipment

29

Circulating pump

It is used to circulate secondary distilled water

30

Demineralize

It maintains the secondary cooling system’s purity

31

An oxygen analyzer is used to measure the amount of dissolved oxygen in the liquid cooling system. The presence of oxygen causes oxidation within the cooling system.

true

32

When inspecting a telltale drain, you discover that it is leaking. What failure does it indicate?

3. The tube joint

33

The overall effectiveness of the heat exchanger is determined by comparing the primary inlet temperature to its outlet pressure. The result of this comparison is best described by what term?

Temperature gradient

34

The device that is inserted in the heat exchanger’s water box to concentrate electrolytic action to it vice to the metal of the heat exchanger’s tubes is made of what material (s)?

2. Zincs only 3. Zinc anode only

35

Who is the best qualified person on board to determine the overall condition of the cooling system?

1. Engineering officer

36

The expansion tank sight glass should normally read in what range?

2/3 to 4/5 full

37

The low-level alarm switch is usually set at 20 percent of tank capacity. The alarm will initially sound when the distilled water level reaches which of the following levels?

20%

38

What term best describes the word makeup water?

1. Distilled water

39

When, if ever, may potable water be used in electronic cooling systems?

never

40

What is the maximum permissible chloride that may be used in cooling system water?

0.065 epm

41

What is an indication that the 1-42. 1-43. 1-44. 1-45. 1-46. 1-47. duplex strainer is clogged?

The pressure reading will be 5 to 10 psi above the clean basket reading

42

If the pressure drop is less than that of a clean basket reading, the basket may be missing.

true

43

The three-way temperature regulating valve is used where seawater is the primary cooling medium, and the two-way valve is used where chilled water is the primary cooling medium.

true

44

The basic operation of both the two-way temperature regulating valve is the same as the three-way temperature regulating valve except that the two-way valve has a manual override feature.

false both have manual override

45

Temperature regulating valve corrective maintenance consists only of visual checks for leaks and corrosion.

false

46

Which of the following devices is used to regulate flow in a seawater cooling system

3. The orifice plate

47

Which of the following flow regulators is used to regulate flow in the chilled water system?

3. The variable orifice (constant Flow regulator)

48

Which of the following devices would be used to protect a cooling system from over pressurization?

4. The relief valve

49

What is the function of a typical low-flow switch?

1. To indicate low coolant flow

50

In a venturi-type flowmeter, the flow rate is measured by what process?

1. The pressure differential

51

Which of the following flowmeters allows visual inspection of the coolant for entrained air?

4. The rotameter-type

52

Operating a circulating pump with insufficient coolant flow could cause which of the following malfunctions?

The overheating of the pump only 2. The seizure of the pump only

53

What percent of the coolant flows through the demineralizer in one hour?

5%

54

Which of the following demineralizer components is used to remove small particles from the coolant?

4. The submicron filter

55

Which of the following contaminations is least likely to occur in a distilled water and ethylene glycol coolant system?

bacterial

56

Demineralize performance and coolant purity is monitored by measuring what property of the coolant?

Conductivity

57

Scheduled maintenance of a demineralizer consists primarily of performing what preventive action?

Replacing the filters and cartridges

58

Which of the following contaminates could be considered a source of contamination for an oxygen analyzer sensor?

Oil from your fingers

59

What position on an alarm switchboard is used for alarm acknowledgement?

standby

60

What position on an alarm switchboard is used to simulate an alarm position?

test

61

What is the first step in isolating the extent of waveguide flooding?

1. Secure the cooling system

62

Which of the following systems comprises the shipboard power distribution system?

1. The casualty power system only 2. The emergency power system only 3. The ship’s service system only

63

What is the function of the switchboard bus ties?

To permit switchboards to be cross connected and to allow paralleling of generators

64

On small ships, centrally locating switchboards (with respect to the load) and feeding them directly from the generators have which of the following advantages?

1. It simplifies the installation 2. It reduces size and weight requirements 3. It reduces equipment requirements

65

Circuit information plates are located on which of the following locations

The distribution panels and bus transfer equipment

66

Why is the phase sequence important to the power distribution system aboard ship?

The phase sequence determines the direction of rotation of three-phase motors

67

What service is provided by bus transfer equipment?

It provides two sources of power to vital ship’s equipment

68

If NORMAL power were to fail supplying the HF transmitter, ALTERNATE power would be restored by the use of which of the following components?

Manual bus transfer (MBT) only

69

Aboard ships, switchgear groups are physically separated as much as practical to achieve what objective?

Afford greater protection from battle damage

70

Which of the following actions is NOT a function provided by switchboards aboard ships?

Automatic shifting of power to alternate sources if normal power is lost

71

What is the purpose of disconnect 2-11. 2-12. 2-13. 2-14. links?

They provide isolation from one switchboard while repairs are being conducted on another

72

The output of all ac generators is developed in what part of the generator?

The armature windings

73

What are the two major assemblies of an ac generator?

Armature and fields

74

Three-phase generators have singlephase windings located what number of degrees out of phase from the other windings?

120° out of phase with the other two windings

75

The three-phase, four-wire, STAR connected power distribution system is also know by what other term?

Wye connected

76

In a transformer, electrical energy is transferred from one circuit to another through which of the following actions?

Electromagnetic induction

77

Energy in a transformer is always transferred without a change in frequency, but you can expect a change in which of the following attributes?

Current and voltage

78

Which transformer winding is designated as the primary winding?

The one that receives energy from an ac source

79

What are the two principle types of transformers?

1. Core and shell

80

Most power supply transformers are designed to operate at frequencies of

50 to 60 HZ

81

Transformers of higher frequencies are of smaller design and permit savings of weight and use of associated equipments.

true

82

The use of varnish to insulate adjacent laminations in a transformer core helps minimize which of the following factors?

Hysteresis losses

83

In transformer lead markings high voltage leads are marked H1, H2, H3, etc. The letter signifies high voltage, what does the number indicate?

The higher the number, the higher the voltage

84

Transformer secondary lead markings are identified by which of the following letters?

X

85

Which of the following types of equipment are used to supply 400 Hertz power to a transformer?

1. Motor-generator units (older) 2. Static converters (newer)

86

What is the primary purpose of the casualty power system?

To make temporary connections to vital circuits

87

Casualty power bulkhead terminals are permanently installed on opposite sides of bulkheads for what reason?

To transfer power through decks without loss of watertight integrity

88

A portable cable used to rig ac casualty power can carry (a) what maximum amount of current and (b) for what maximum number of hours?

(a) 200 A (b) 4 hours

89

Shore power connections aboard ship may be used to supply power to another ship alongside.

true

90

When testing shore power cables, you should use which of following grounds as a shore ground resistance?

The ship’s hull or metal ext

91

What is the key component of the phase-sequence indicator?

1. The three-phase induction motor