Electrics

Question 1

What is the purpose of the GEN switch/lights on the ELEC panel?

Answer 1

To reset or turn OFF the applicable generator

Question 2

What is the electrical rating of the variable frequency generators, APU generator, and the RAT?

Answer 2

VFGs: 40kVA
APU gen: 40kVA
RAT: 9kVA

Question 3

In an emergency, what buses are powered by the batteries?

Answer 3

BATT BUS and DC EMER BUS

Question 4

How many AC buses are on the GLEX?

Answer 4

8 total:
4 AC buses - 1,2,3,4 (ACPC)
4 AC buses - 1A, 2A, 3A, ESS (CCBP)

Question 5

What electrical services are powered in GROUND SERVICE mode?

Answer 5

Four primary AC buses, cabin feeders, APU battery charger and heater. AC3 (CCBP) then powers the avionics battery charger and heater.

Question 6

Where is the EXT DC power receptacle located?

Answer 6

Aft of the AFT equipment compartment door

Question 7

As the aircraft decelerates on approach, at what airspeed does the RAT generator go offline?

Answer 7

Below 147kts

Question 8

What is the normal power source of DC power for the aircraft?

Answer 8

Four TRUs located in the unpressurised nose compartment:
TRU1
TRU2
ESS TRU1
ESS TRU2

Question 9

What are the four main DC buses?

Answer 9

DC Bus 1
DC Bus 2
DC ESS Bus
BATT Bus

Question 10

What is indicated when both the AVAIL and ON lights on the EXT AC switch/lights illuminate simultaneously?

Answer 10

GROUND SERVICE switch has been left ON

Question 11

What does the EICAS warning message EMER PWR ONLY indicate?

Answer 11

RAT is powering the AC ESS BUS

Question 12

In cruise flight, when does the RAT automatically deploy?

Answer 12

14 secs after loss of all AC power

Question 13

In the event of a single generator operation, which AC buses remain powered?

Answer 13

AC buses 1 and 4

Question 14

Where is the external power receptacle located?

Answer 14

Aft service control panel

Question 15

In an emergency, how long will the aircraft batteries provide DC power?

Answer 15

Minimum 15 mins

Question 16

Can a thermal CB be reset from the EMS CDU?

Answer 16

No. A thermal CB can only be physically reset at its location

Question 17

How many engine generators must fail before AC buses are load shed by the ACPC?

Answer 17

Three

Question 18

What is the purpose of the EMER PWR OVRD switch?

Answer 18

Provides a bypass of a failed DCPC to provide power from ESS TRU 1 and 2 to the secondary power distribution assemblies (SPDAs)

Question 19

Why must the GROUND SERVICE switch be selected to OFF prior to selecting normal external power

Answer 19

TAT3 and right windshield heaters will remain inoperative

Question 20

What EICAS message is displayed for a failed battery charger?

Answer 20

Advisory message APU BATT CHGR FAIL or AV BATT CHGR FAIL

Question 21

Why is the RAT generator taken offline as the aircraft decelerates on approach?

Answer 21

To ensure the RAT HYD pump has priority for flight controls

Question 22

What does the AVAIL light on the EXT AC switch/light on the aft service control panel indicate?

Answer 22

That the correct phase, voltage, and frequency of EXT AC power is connected and available

Question 23

When would the RAT automatically deploy?

Answer 23

Loss of all AC power, and the slat/flap handle not IN/0º, or immediately after dual engine failure

Question 24

What is powered with external DC power?

Answer 24

APU start contactor assembly (ASCA) provides power to start the APU if the APU battery is not available

Question 25

What are the sources of aircraft-generated AC power?

Answer 25

Four VFGs, one APU generator, one RAT

Question 26

What is the purpose of the ACPC?

Answer 26

To protect, control, and distribute AC power to the main AC buses

Question 27

If a generator is reset after the RAT has deployed, how can normal power be restored?

Answer 27

Select the RAT generator OFF with the RAT MANUAL RELEASE handle in the stowed position

Question 28

Which DC buses are automatically load shed during a single TRU operation?

Answer 28

DC BUS 1 and DC BUS 2