Electrical

Question 0

What happens if a power generating source fails?

Answer 0

Bus ties automatically connect to provide no system degradation

Question 1

How many networks make up the electrical system?Why?

Answer 1

2 indenpendent networks

Redundancy and fault isolation

Question 2

What components power the AC system?

Answer 2

2 Integrated drive generators IDGs
Auxillary power unit APU
Inverter
Ram Air Turbine RAT
AC GPU receptacle

Question 3

What components power the DC system?

Answer 3

2 NiCad batteries
3 TRUs Transformer rectifier units
DC GPU receptacle

Question 4

How does the IDG maintain a stable power output?

Answer 4

A constant speed Drive attached the IDG to the AGB accessory gear box

Question 5

What monitors and controls the IDGs?

Answer 5

Each has a generator Control Unit GCU

Question 6

Can one IDG supply power to the entire system?

Answer 6

Yes

Question 7

What causes the amber IDG light on the overhead panel to illuminate?

Answer 7

High oil temp.

Low oil pressure

Question 8

If an IDG is manually disconnected can it be reconnected in air?

Answer 8

No only maintance can reconnect it and only on the ground.

Question 9

What is the primary purpose to the AC generators?

Answer 9

To power The AC busses and AC ESS bus which

Powers the 3 TRUs 1,2, ESS

Question 10

What are the purpose of the TRUs?

Answer 10

To convert 115vac power to 28vdc

Question 11

Can the APU replace a failed IDG

Answer 11

Yes

Question 12

What is the AC electrical systems priority?

Answer 12

Outside (IDG) inside(APU) outside(GPU) cross side

Question 13

How is it know that an AC GPU is hooked up to the airplane and ready to provide electricity?

Answer 13

GPU button will display AVAIL and the GPU icon is presented on theelectrical synoptic page

Once the GPU button is pushed in the button will display IN USE provided another AC power source is not available.

Question 14

What does it mean if the AC GPU is plugged in and the GPU panel button displays IN USE?

Answer 14

Ground service bus is in use

Cockpit GPU button will display AVAIL even though the ground service bus is in use

Question 15

If the airplane is using the AC GPU and the APU is started what should the pilot be sure to do?

Answer 15

Deselect the GPU button before the next GPU connection

Question 16

What will charge the batteries?

Answer 16

Any AC power source

Question 17

How Long will the aircrafts battieries last with no recharging?

Answer 17

10 mins

Question 18

What is the purpose of the DC GPU receptacle?

Answer 18

For APU start when batteries -20*C

Question 19

What is the minimum battery temp for APU start?

Answer 19

-20*C

Question 20

What is the minimum battery voltage to close the battery busties?

Answer 20

18Volts

Question 21

What battery is used for APU start?

Answer 21

Both
Batt 2 powers the APU start bus
Batt 1 powers the FADEC and EICAS for monitoring

Question 22

What is the purpose of the inverter?

Answer 22

Converts 28 VDC from the batteries to115VAC to power the AC standby BUS whenan AC source is not available

Question 23

What is on the AC standby BUS?

Answer 23

Engine exciters 1a and 2a

Question 24

What powers the RAM air turbine (RAT)?

Answer 24

Airflow turns the RAT propeller which spins the turbine inside

Question 25

When will the RAT deploy?

Answer 25

Automatically deploys if the AC Busses are not powered

Manually by pilot

Question 26

How long after deployment before the RAT will supply power?

Answer 26

8 seconds