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M11 New > 11.6 > Flashcards

11.6 Flashcards

1
Q

Ac and dc voltages

A

Ac 115

Dc 28 -> 24

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2
Q

In a 3 phase system what’s the voltage between each phase

A

120

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3
Q

How long is emergency power from the battery for

A

At least 30m

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4
Q

What is the battery used for

A

Emergency power and apu start

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5
Q

What power source does the EDG provide during flight

A

Dc power source

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6
Q

Why do we need vents on batteries

A

Gas to escape and prevent spillage

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7
Q

How can you disconnect the battery in an emergency

A

By hand no need for wire cutters

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8
Q

Cell voltage when discharged and charging

A

1v when discharged

1.5v when charging

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9
Q

How often does maintenance occur on batteries

A

Every 2000 hours but never performed on aircraft

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10
Q

Why is it necessary to avoid too many apu starts

A

Overheat the battery which reduces electrolyte level and melts plastic separator

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11
Q

What voltage should you not discharge a battery

A

Under 22v

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12
Q

What should you monitor on ni cad batteries

A

The voltage and current during charging

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13
Q

What battery is constant voltage

A

Lead acid

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14
Q

What battery is constant current

A

Ni cad

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15
Q

When removing a battery what do you disconnect first and why

A

Negative lead to prevent shorts

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16
Q

What is lead acid electrotype topped up with

A

Distilled water only

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17
Q

What are the characteristics of lithium ion batteries

A

8 cells

28dc

75amph

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18
Q

What’s the advantages of lithium ion batteries

A

30% lighter

Quicker recharge

No memory degradation

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19
Q

Lithium ion charging stage

A

Constant current

Balence

Voltage source

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20
Q

Source of power for DC

A

Battery

External

Generators

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21
Q

How does the generator state the direction of rotation

A

On the identity plate or an arrow on the stator externally

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22
Q

What does a tru do

A

Turn ac into dc voltage at 28v or 14v

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23
Q

How does the parallel system work

A

Two or more generators connected to the sync bus

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24
Q

How does non-parallel work

A

All the loads are supplied through the bus bar

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25
Q

What does an equalising coil do

A

Makes sure the power supplied or consumed by the IDG is equal

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26
Q

What happens if one of the generators fails and bus tie breaker closes

A

The two bus bars connect with serviceable generator to supply both busbars

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27
Q

What 3 things generate ac current

A

Ac generators

Static inverters

Rotory inverters

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28
Q

What phase is ac generation

A

Three phase 400hz

115/200v

29
Q

How is generator output controlled in ac

A

Integrated control and protection unit

30
Q

What is AC wild

A

Faster the rotor turns, the higher the frequency

31
Q

What does a csd do

A

Adapts variable engine speed into constant

32
Q

What’s the purpose of fly weights

A

Keeps output at 400hz

33
Q

What’s the oil circuit used for

A

Cooling and lubrication

34
Q

What does a generator rotor do

A

Increase or decrease voltage of frequency outlet

35
Q

What the two temperature indications

A

Absolute oil temperature and rise in temperature

36
Q

What is underspeed

A

Input speed drops below normal control range

37
Q

What a constant speed drive disconnect

A

Electrically actuated device that decouples the input shaft from the input spline shaft if futures transmission malfunction

38
Q

How do you know if the csd disconnection is successful

A

Voltage and frequency will display 0

39
Q

How do you operate the disconnect button

A

Press no longer then 3 seconds

Don’t press more then once every 60 seconds

40
Q

How does the constant speed drive unit work

A

Concert variable engine rpm to generator speed of 12000 rpm

41
Q

What type of generator is csdu and what does it output

A

Brushless

200v at 400hz and also 90kva continuously

42
Q

What are the 3 gcu functions

A

Regulation

Protection

Switching

43
Q

What is a current transformer

A

Used as an amp clamp

44
Q

Is there physical contact between cables and the transformer

A

No

45
Q

How is emergency power generated

A

Battery and ram air turbine

46
Q

What bus is the battery connected to

A

Hot battery bus

47
Q

What is the essential bus connected to

A

Anything that will allow the aircraft to fly safe

48
Q

What is voltage regulation done by

A

Gcu

49
Q

How are the poles ordered

A

Always in pairs

50
Q

How are poles ordered in DC

A

2,4,6 poles

51
Q

What is an inverter

A

Dc to ac

28vdc becomes 26vac or 115vac

52
Q

What inverter is better

A

Static as it quieter and has no moving parts

53
Q

What does a transformer do

A

Steps voltage and current up & down

Current and voltage work in opposite

54
Q

What are rectifiers and the 2 types

A

Change ac to dc

Half wave & full wave

55
Q

What does a tru do

A

Convert 115vac from engine or apu to 28vdc

56
Q

What is main power distribution

A

Electrical power to main consumers

57
Q

Who is the emergency power distribution for

A

Consumers that can land aircraft safely

58
Q

What are fuse and circuit breakers used to do

A

Prevent currents Higher then the maximum of the cross sectional area

59
Q

What do you do with a blown fuse

A

Replace after blown

60
Q

What do you when a circuit breaker pops

A

Reset after the circuit fault is removed

61
Q

How many times can you replace a circuit breaker in flight

A

Once

62
Q

Why are circuit breakers used as manual on/off switches

A

To allow deviation of circuits

63
Q

What is a short circuit

A

Hard short between high voltage side to ground or different potential difference

64
Q

What type of cb is push/pull pop out

A

Single-pole thermal device

65
Q

What is the most common circuit breaker

A

Thermal & magnetic or electromagnetic

66
Q

What voltage does an external ground power unit supply

A

115vac and 28vdc

67
Q

How many pins in dc got

A

3 pins
2 positive
1 negative

68
Q

How many pins does an ac gpu have

A

6 pins
4 larger ones
2 smaller

69
Q

In an AC gpu what are the 4 pins

A

Phase A B C & nuetral

M11 New (17 decks)

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