ORAL* E145 Electrical

Question 1

Is Airplane predominately AC or DC?

Answer 1

DC

Question 2

How many generators are there?

Answer 2

4 engine, 1 APU

Question 3

When generators are on number 1 engine?

Answer 3

1 and 3

Question 4

Which generators are on the right engine?

Answer 4

2 and 4

Question 5

Max amperage on Engine Gens?

Answer 5

400 amps

Question 6

Max amps draw APU?

Answer 6

400 amps up to 30k…300 amps 30k and above

Question 7

Battery Voltage and amps?

Answer 7

24 volt, 44 amps nicad

Question 8

Where are batteries

Answer 8

Front electronics compartment…left side

Question 9

Does Ground Power charge batteries?

Answer 9

No

Question 10

Minimum battery temp for APU start?

Answer 10

-20c

Question 11

Backup battery volts and amps

Answer 11

24 volt 5 amp lead acid

Question 12

Inverter Specs?

Answer 12

250 VA/400 hz single phase…output 115 VAC

Question 13

What bus powers inverter?

Answer 13

DC bus 1

Question 14

what is the EDL?

Answer 14

Electrical Distribution Logic…controls tie contactors

Question 15

All 4 generators are online…what are positions of bus tie contractors?

Answer 15

Bus tie 1 is open (off) and Bus tie 2 is closed (on)

Question 16

GEN OVLD caution happens when?

Answer 16

Greater than 400 amps

Question 17

GPU should supply at least ______amps?

Answer 17

300

Question 18

If GPU is connected and on what light is on?

Answer 18

GPU AVAIL

Question 19

What should GPU voltage show on MFD when connected and availbale>

Answer 19

26-29 VDC

Question 20

Which has priority…Generators or GPU?

Answer 20

GPU takes over when connected

Question 21

Which bus is powered with batteries OFF and GPU selected?

Answer 21

Ground Service Bus

Question 22

What is powered by Ground Service Bus?

Answer 22

LIGHTS......
Stair Lights
Dome Light
Galley Lights
Cabin Lights,
Lav Lights
Baggage and Service Compartment Lights

Question 23

what is an electrical emergency?

Answer 23

Loss of all generators

Question 24

Batteries can supply essential power for how long?

Answer 24

40 minutes…includes 3 APU start attempts

Question 25

In Normal ops…battery 1 is connected parallel with GENS

Answer 25

1 and 3

Question 26

Battery 2 normally runs in parallel with GENS

Answer 26

2 and 4

Question 27

Which battery starts the APU

Answer 27

Battery 2

Question 28

What happens to battery 1 during APU start?

Answer 28

It’s isolated Battery 1 contactor opens

Question 29

Battery AUTO switch does what?

Answer 29

Battery contactors controlled by the EDL

Question 30

GPU is connected and selected on…what do battery contractors do?

Answer 30

OPEN….they disconnect the batteries. Batteries cannot be charged with GPU

Question 31

with battery power only on ground, do you have shed busses?

Answer 31

No

Question 32

How can you connect shed busses on ground?

Answer 32

SHED BUSES OVRD and at least one generator

Question 33

BATT OVTEMP happens when

Answer 33

More the 70 C

Question 34

Batteries less than 24v after APU start…what’s required?

Answer 34

APU must run 30 minutes to recharge

Question 35

What does Back Up Battery on Overhead panel do?

Answer 35

Backup Battery charging…

Question 36

when do EDG come on line?

Answer 36

56.4 N2

Question 37

How many gen resets?

Answer 37

1

Question 38

What 3 electrical sources can start APU?

Answer 38

GPU, Battery 2, or Battery 2 with Main gen assist

Question 39

What does backup battery power?

Answer 39

Backup hot bus, which includes the 5 GCU’s and the EDL

Question 40

Can battery 1 start APU?

Answer 40

no

Question 41

APU powers which bus?

Answer 41

CENTRAL DC

Question 42

When does APU come on online?

Answer 42

95% plus 7 seconds

Question 43

On ground when are all DC buses on?

Answer 43

a. At least 3 gens. online
b. GPU on and connected
c. One generator running and SHED OVRD

Question 44

Explain electrical config with 4 or 5 generators online

Answer 44

Left and right networks are isolated and all buses are energized

Question 45

Explain electrical config with 3 gens online

Answer 45

one network connected through bus tie contactors which are closed…all buses eneergized

Question 46

Explain elec configuration with 1 or 2 gens online

Answer 46

Same as with 3 but shed buses drop out (one network, bus tie contactors both closed)

Question 47

electrical emergency…no generators (in flight)

Answer 47

Batteries only power Essential Euses only

Question 48

Which displays still work in emergency power?

Answer 48

EICAS, RMU 1 and 2, and the ISIS

Question 49

what do avionics master buttons on overhead do?

Answer 49

Allow shutting off radios and nav during APU start to avoid spikes

Question 50

Inverter Powers what?

Answer 50

TCAS, EGPWS

Question 51

BTC 1 position with Gen 1 fail and APU off

Answer 51

closes

Question 52

BTC 1 portion with Gens 1 fail and APU on

Answer 52

opens

Question 53

What do you do is auto transfer fails with a loss of all generators?

Answer 53

Push Essential Power button

Question 54

How do you know if automatic transfer fails with a loss of all generators?

Answer 54

Displays still work

Question 55

What does Essential Power button do?

Answer 55

Overrides EDL, and makes sure batteries are only powering the essential buses

Question 56

What does SHED BUSES OVRD do?

Answer 56

closes shed buses contactor

Question 57

Will SHED BUSES OVRD work in flight?

Answer 57

Nope

Question 58

What does BUS TIES OVRD do?

Answer 58

Closes BTC’s except in overcurrent

Question 59

When is APU not seen on MFD

Answer 59

APU off and less than 10% RPM

Question 60

If airplane will sit for long period what are battery considerations

Answer 60

Remove if temps below -15c, and batteries must be removed to recharge if volts are below 19VDC