11.8 Flashcards

1
Q

Uses of electrical power

A

Electrical heating
Lighting
Mechanical power
Electronic devices

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Lighting equipment is used where

A

Cockpit
Cabin area
Outside

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why light cockpit

A

Illuminate panels , maps , instruments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why light outside aircraft

A

Visability to other aircraft
Illuminate ground during take off/ landing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

2 electrical power subsystems

A

Generation subsystem
Distribution subsystem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How is ac power generated

A

By engines during flight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How is ac generated in an emergency

A

By hydraulic motor or propeller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How many generators per engine for ac supply

A

1 per engine
787 has 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do you convert ac to dc

A

TRU

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is ac voltage distributed

A

115v at 400hz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How many phases is ac voltage generated

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

% of energy supply ac consumers need

A

95

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the ac voltage consumers

A

Heating
Lighting
Mechanical equipment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How many sources does dc voltage come from

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the sources of dc voltage

A

Tru - convert 115v ac to 28v dc

Nickel cadmium Battery - gives 24v dc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

% of energy dc consumers use

A

5%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are dc consumers

A

Electrical equipment
Control and monitoring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the dc generators

A

Alternators and starter generator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What do batteries do in dc

A

Provide power for emergency distribution, apu starting and engine start

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Power distribution parts

A

Main , essential , emergency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is essential power distribution for

A

Allow safe flying

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is emergency power distribution for

A

Safe landing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does a bus do

A

Connects power source to electrical consumer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How many ac buses

A

3 main buses , one for each phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What does load shedding do

A

Improves reliability of power relays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How is manual load shedding done

A

Via push button

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What’s auto load shedding used for

A

Prevent overload or detect overload of generators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Where is emergency power available

A

Aircraft battery , power for 30 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Where does dc voltage go in emergency power

A

24v dc to dc bus

30
Q

Where does ac voltage go in emergency power

A

115v ac after static inverter to ac emergency bus

31
Q

where does dc voltage go in emergency power

A

28v dc via tru to dc bus

31
Q

3 disrupter components

A

power relays
circuit breakers
current transformers

31
Q

boeing emergency power switching

A

via switch

31
Q

where are fuses used

A

high current devices, easiest method of overcurrent protection

31
Q

airbus emergency power switching

A

push button

32
Q

how does a fuse or cb work

A

prevents currents higher then maximum allowed for cross section of wire

32
Q

relays for AC

A

contactors &
breakers

32
Q

purpose of a fuse or cb

A

prevent overheating and fire due to short circuit

32
Q

AC line to nuetral voltage

A

115v

32
Q

why are cb’s replacing fuses

A

reset quickly and have manual on/off switches for deactivation

32
Q

AC line to line voltage

A

200v

32
Q

whats a orange colour cb

A

pulled by flight crew

32
Q

whats a grey collar cb

A

pulled during maintainece

32
Q

purpose of csd’s

A

add or subtract speed

33
Q

whats a red safety clip cb

A

prevent cb from closing

33
Q

whats a red safety tag cb

A

used during ground maintenance

33
Q

advantages to 3 phase ac generation

A

2 different voltage levels without additional equipment needed

33
Q

when monitoring what are the green knobs for

A

essential systems

34
Q

what do you do in low speed range

A

increase speed

35
Q

what do you do in high speed range

A

decrease speed

36
Q

what’s the low speed region operation

A

overdrive

37
Q

what’s the high speed region operation

A

underdrive

38
Q

whats straight drive used for

A

acceleration & deceleration

39
Q

how is DC power generated

A

via the TRU

40
Q

how many busses per TRU

A

1

41
Q

what does the TRU do

A

convert 115v AC into 28v DC

42
Q

purpose of battery

A

emergency power & apu starter motor power

42
Q

how many batteries do aircraft use

A

1,2, or 3

43
Q

whats the most common battery type

A

nickel cadmium

44
Q

advantage of nickel cadmium batteries

A

less maintenance costs & low temperature performance

45
Q

what does workshop check for in batteries and when

A

check for good battery condition , checked every 2000 operating hours

46
Q

nickel cadmium saftey tips

A

special care when charging and discharging , don’t discharge battery under 22v

47
Q

what are lithium ion batteries used for

A

large amount of power in a short period and high energy tasks such as jet engine start up

48
Q

how many cells doe a lithium ion battery have

A

8 cells which produce 28v dc at 75amp

49
Q

what makes lithium ion better then nickel cadmium

A

30% lighter , improved power quality, compact

50
Q

how is ground power supplied

A

1 external source or 1 apu generator

51
Q

ground power supply for large aircraft

A

2 or 4 external power sources and up to 2 APU generators

52
Q

how many pins in a receptacle

A

6
4 thick pins , 2 shorter thinner pins

53
Q

what does holding strap do

A

supports weight of cable

54
Q

how is towing power supplied

A

only using aircraft battery

55
Q

why cant you carry too many apu starts immediately after each other

A

battery cell overheats and reduces electrolyte level and can melt plastic separator