Electrics Flashcards
What is the purpose of the GEN switch/lights on the ELEC panel?
To reset or turn OFF the applicable generator
What is the electrical rating of the variable frequency generators, APU generator, and the RAT?
VFGs: 40kVA
APU gen: 40kVA
RAT: 9kVA
In an emergency, what buses are powered by the batteries?
BATT BUS and DC EMER BUS
How many AC buses are on the GLEX?
8 total:
4 AC buses - 1,2,3,4 (ACPC)
4 AC buses - 1A, 2A, 3A, ESS (CCBP)
What electrical services are powered in GROUND SERVICE mode?
Four primary AC buses, cabin feeders, APU battery charger and heater. AC3 (CCBP) then powers the avionics battery charger and heater.
Where is the EXT DC power receptacle located?
Aft of the AFT equipment compartment door
As the aircraft decelerates on approach, at what airspeed does the RAT generator go offline?
Below 147kts
What is the normal power source of DC power for the aircraft?
Four TRUs located in the unpressurised nose compartment: TRU1 TRU2 ESS TRU1 ESS TRU2
What are the four main DC buses?
DC Bus 1
DC Bus 2
DC ESS Bus
BATT Bus
What is indicated when both the AVAIL and ON lights on the EXT AC switch/lights illuminate simultaneously?
GROUND SERVICE switch has been left ON
What does the EICAS warning message EMER PWR ONLY indicate?
RAT is powering the AC ESS BUS
In cruise flight, when does the RAT automatically deploy?
14 secs after loss of all AC power
In the event of a single generator operation, which AC buses remain powered?
AC buses 1 and 4
Where is the external power receptacle located?
Aft service control panel
In an emergency, how long will the aircraft batteries provide DC power?
Minimum 15 mins
Can a thermal CB be reset from the EMS CDU?
No. A thermal CB can only be physically reset at its location
How many engine generators must fail before AC buses are load shed by the ACPC?
Three
What is the purpose of the EMER PWR OVRD switch?
Provides a bypass of a failed DCPC to provide power from ESS TRU 1 and 2 to the secondary power distribution assemblies (SPDAs)
Why must the GROUND SERVICE switch be selected to OFF prior to selecting normal external power
TAT3 and right windshield heaters will remain inoperative
What EICAS message is displayed for a failed battery charger?
Advisory message APU BATT CHGR FAIL or AV BATT CHGR FAIL
Why is the RAT generator taken offline as the aircraft decelerates on approach?
To ensure the RAT HYD pump has priority for flight controls
What does the AVAIL light on the EXT AC switch/light on the aft service control panel indicate?
That the correct phase, voltage, and frequency of EXT AC power is connected and available
When would the RAT automatically deploy?
Loss of all AC power, and the slat/flap handle not IN/0º, or immediately after dual engine failure
What is powered with external DC power?
APU start contactor assembly (ASCA) provides power to start the APU if the APU battery is not available
What are the sources of aircraft-generated AC power?
Four VFGs, one APU generator, one RAT
What is the purpose of the ACPC?
To protect, control, and distribute AC power to the main AC buses
If a generator is reset after the RAT has deployed, how can normal power be restored?
Select the RAT generator OFF with the RAT MANUAL RELEASE handle in the stowed position
Which DC buses are automatically load shed during a single TRU operation?
DC BUS 1 and DC BUS 2
