Electrical Flashcards
In descending order, the priority for electrical power is
onside gen, external power, APU, remaining engine gen
What is a characterict of the APU electrical system
Can power the entire airplane on the ground
what is a characteristic of the electrical system
system operation is normaly automatic
The bus tie contactors open or close automatically to maintain power supply to AC busses 1 and 2 when the bus tie switch is in the ___position
AUTO (lights out)
With the APU running and external power plugged in, what is the indication that the APU generator is powering the AC tie bus?
EXT PWR AVAIL light illuminated
EXT PWR AVAIL light indicates external power is
plugged in and electrical parameters are normal
EXT PWR AVAIL light indicates external power is
plugged in and electrical parameters are normal
following pushback, what is the configuration of the electrical system when engine 1 is running and the APU is operating
GEN 1 POWERS AC bus 1 and APU generator powers AC bus 2
Do not hold the IDG disconnect switch for more than ___ to prevent possible damage to the disconnect mechanism
3 sec
in the event of a single IDG failure the remaining IDG powers
the entire electrical system, except for the main galley bus
do not disconnect the IDG when the
engine is not running or not windmilling
if the IDG 1 switch is pushed in-flight
IDG 1 can only be reconnected on the ground by maintenance
what occurs when an IDG is disconnected?
the corresponding generator can no longer supply power
GALY & CAB FAULT light indicates
A generator load exceeds 100% of rated output
A GEN FAULT light indicates
The line contactor is open without selecting the respective GEN switch OFF
In flight, with only one engine generator operating, how is the electrical system configured?
The main galley power supply is automatically shed
In the event of a TR failure, how is the DC system reconfigured?
DC busses 1 and 2 will interconnect through the DC BAT bus. ESS TR powers the DC ESS bus
With a loss of TR 1, what pilot action is required
no action, is atuomatically, powers DC bus 1 with TR 2
In the normal configuration, which bus feeds the AC ESS bus?
AC bus 1
AC ESS FEED FAULT light
illuminates amber when AC ESS bus is not electrically powered
What bus provides an alternate source of power for the AC ESS bus?
AC bus 2
to power the AC essential bus from AC bus 2 due to a loss of AC bus 1 what pilot action is required
no action, syst is automatic
what occurs with the AC and DC ESS SHED busses when the airplane is on battery power only
both busses are shed
what is a characteristic of the battery power system?
An automatic cutoff logic prevents the batteries from becoming completely discharged on the ground
