Electrics Flashcards
Primary external power powers?
R main bus
R transfer bus
Secondary external power powers?
L Main bus
L Transfer bus
Electric system provides what powers?
AC & DC
Sources of main AC power are?
L & R IDGs
APU gen
External power
How many AC power sources are needed to power the entire AC?
2
Sources of DC power are?
4 TRUs
2 PMGs - Flt cntl DC elec sys
Main battery
APU battery
If all electrics off the main battery still powers what? Which provides?
Hot battery bus
APU fire extinguisher
Engine fire extinguisher
ADIRU
Ground handling bus automatically powered when? Used for?
When Primary external power available.
Used for cargo handling, fuelling, other ground operations
Ground service bus does? When powered?
Gives interior cabin lights & plug sockets.
Switched on at door L1
Auto Powered when R main AC bus powered
Normally Main AC busses get power from?
Respective IDGs
ELMS load shedding removes? And repowers?
Galleys
Utility busses
Individual items
Re powers in reverse order
At the gate with PRI ext power on you start the APU, what powers what?
PRI EXT powers: R main R XFR
APU powers: L Main L XFR
After arriving at the gate with PRI EXT power AVAIL selecting it on will? (No APU)
Power L & R MAin AC busses - removes IDG sources
BUGS automatically power the
Transfer busses when needed.
If both main AC busses fault How many BUGS do what?
Only 1 BUG will power both L & R transfer busses
During an auto land approach what happens to the electrical system when approach is selected?
1 BUG energises a XFR bus ( redundancy)
DC electric system compromises of
Main DC power
Flt cntl DC system
C1 TRU powers
Battery bus
Capts flight instruments
(And gives a back up for FOs and C flight controls)
The standby electric system can provide AC & DC power to? In the event of a total power loss.
Selected instruments
Comms
Nav systems
Flight control systems
Standby system is usually powered by?
TRUS
RATs main priority is?
What powers standby?
Hydraulics
Main battery powers standby elec system.
If the RAT is supplying electrical power what is available to pilots?
BOTH FO & CAPT flight instruments
If main battery is providing electrical power only what do you have?
CAPT flight instruments only
If L & R bus tie breakers are closed is means the AC power is supplied by how many systems?
1
When a single IDG is operating and external power connected what happens?
Single IDG powers both L & R main busses, kicks off external power
Standby electrical system is made up of?
Main battery
Standby inverter
RAT generator and generator control unit
