11.8

Question 1

Uses of electrical power

Answer 1

Electrical heating
Lighting
Mechanical power
Electronic devices

Question 2

Lighting equipment is used where

Answer 2

Cockpit
Cabin area
Outside

Question 3

Why light cockpit

Answer 3

Illuminate panels , maps , instruments

Question 4

Why light outside aircraft

Answer 4

Visability to other aircraft
Illuminate ground during take off/ landing

Question 5

2 electrical power subsystems

Answer 5

Generation subsystem
Distribution subsystem

Question 6

How is ac power generated

Answer 6

By engines during flight

Question 7

How is ac generated in an emergency

Answer 7

By hydraulic motor or propeller

Question 8

How many generators per engine for ac supply

Answer 8

1 per engine
787 has 2

Question 9

How do you convert ac to dc

Answer 9

TRU

Question 10

How is ac voltage distributed

Answer 10

115v at 400hz

Question 11

How many phases is ac voltage generated

Answer 11

3

Question 12

% of energy supply ac consumers need

Answer 12

95

Question 13

What are the ac voltage consumers

Answer 13

Heating
Lighting
Mechanical equipment

Question 14

How many sources does dc voltage come from

Answer 14

2

Question 15

What are the sources of dc voltage

Answer 15

Tru - convert 115v ac to 28v dc

Nickel cadmium Battery - gives 24v dc

Question 16

% of energy dc consumers use

Answer 16

5%

Question 17

What are dc consumers

Answer 17

Electrical equipment
Control and monitoring

Question 18

What are the dc generators

Answer 18

Alternators and starter generator

Question 19

What do batteries do in dc

Answer 19

Provide power for emergency distribution, apu starting and engine start

Question 20

Power distribution parts

Answer 20

Main , essential , emergency

Question 21

What is essential power distribution for

Answer 21

Allow safe flying

Question 22

What is emergency power distribution for

Answer 22

Safe landing

Question 23

What does a bus do

Answer 23

Connects power source to electrical consumer

Question 24

How many ac buses

Answer 24

3 main buses , one for each phase

Question 25

What does load shedding do

Answer 25

Improves reliability of power relays

Question 26

How is manual load shedding done

Answer 26

Via push button

Question 27

What’s auto load shedding used for

Answer 27

Prevent overload or detect overload of generators

Question 28

Where is emergency power available

Answer 28

Aircraft battery , power for 30 minutes

Question 29

Where does dc voltage go in emergency power

Answer 29

24v dc to dc bus

Question 30

Where does ac voltage go in emergency power

Answer 30

115v ac after static inverter to ac emergency bus

Question 31

where does dc voltage go in emergency power

Answer 31

28v dc via tru to dc bus

Question 31

3 disrupter components

Answer 31

power relays circuit breakers current transformers

Question 31

boeing emergency power switching

Answer 31

via switch

Question 31

where are fuses used

Answer 31

high current devices, easiest method of overcurrent protection

Question 31

airbus emergency power switching

Answer 31

push button

Question 32

how does a fuse or cb work

Answer 32

prevents currents higher then maximum allowed for cross section of wire

Question 32

relays for AC

Answer 32

contactors & breakers

Question 32

purpose of a fuse or cb

Answer 32

prevent overheating and fire due to short circuit

Question 32

AC line to nuetral voltage

Answer 32

115v

Question 32

why are cb's replacing fuses

Answer 32

reset quickly and have manual on/off switches for deactivation

Question 32

AC line to line voltage

Answer 32

200v

Question 32

whats a orange colour cb

Answer 32

pulled by flight crew

Question 32

whats a grey collar cb

Answer 32

pulled during maintainece

Question 32

purpose of csd's

Answer 32

add or subtract speed

Question 33

whats a red safety clip cb

Answer 33

prevent cb from closing

Question 33

whats a red safety tag cb

Answer 33

used during ground maintenance

Question 33

advantages to 3 phase ac generation

Answer 33

2 different voltage levels without additional equipment needed

Question 33

when monitoring what are the green knobs for

Answer 33

essential systems

Question 34

what do you do in low speed range

Answer 34

increase speed

Question 35

what do you do in high speed range

Answer 35

decrease speed

Question 36

what's the low speed region operation

Answer 36

overdrive

Question 37

what's the high speed region operation

Answer 37

underdrive

Question 38

whats straight drive used for

Answer 38

acceleration & deceleration

Question 39

how is DC power generated

Answer 39

via the TRU

Question 40

how many busses per TRU

Answer 40

1

Question 41

what does the TRU do

Answer 41

convert 115v AC into 28v DC

Question 42

purpose of battery

Answer 42

emergency power & apu starter motor power

Question 42

how many batteries do aircraft use

Answer 42

1,2, or 3

Question 43

whats the most common battery type

Answer 43

nickel cadmium

Question 44

advantage of nickel cadmium batteries

Answer 44

less maintenance costs & low temperature performance

Question 45

what does workshop check for in batteries and when

Answer 45

check for good battery condition , checked every 2000 operating hours

Question 46

nickel cadmium saftey tips

Answer 46

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

Question 47

what are lithium ion batteries used for

Answer 47

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

Question 48

how many cells doe a lithium ion battery have

Answer 48

8 cells which produce 28v dc at 75amp

Question 49

what makes lithium ion better then nickel cadmium

Answer 49

30% lighter , improved power quality, compact

Question 50

how is ground power supplied

Answer 50

1 external source or 1 apu generator

Question 51

ground power supply for large aircraft

Answer 51

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

Question 52

how many pins in a receptacle

Answer 52

6 4 thick pins , 2 shorter thinner pins

Question 53

what does holding strap do

Answer 53

supports weight of cable

Question 54

how is towing power supplied

Answer 54

only using aircraft battery

Question 55

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

Answer 55

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