Electrical Flashcards
Why would APU GEN OFF light illuminate
Generator break open because of a Fault
Switch selected off
When does Bus Tie ISLN light illuminate
Fault occurred
Bus Tie Switch pushed out
GEN CONT switches
On
Off
On - arms the gen breaker to close automatically
Off - opens gen breaker
Resets fault trip circuitry
GEN DRIVE DISC switches
Off - disconnects the Gen Drive
Has to be reconnected by MX
GEN DRIVE switch - DRIVE light illuminates when
Gen drive Oil low pressure/high temperature
What happens when you turn the BATT switch to ON
A few Annunciator lights illuminate
Allows for the Apu to start
STBY Power Selector
Off/Auto/Bat
What does each position mean
Off - Stby busses unpowered
Auto - Stby busses transfer to Bat if AC power is lost
Bat - Stby busses powered from Main & APU batteries
STBY POWER off light means
AC or DC stby bus unpowered
Purpose of Hydraulic Driven Generator
Operates automatically as backup source of power in the event of a loss of both AC busses
Source order for powering Main Busses
Respective IDG
APU
Opposite IDG
Do we have control of the Galley buses
Yes, but pressing/depressing the Utility Bus switches
Which bus normally powers the Ground Service Bus
Right Main AC Bus
What does the Ground Service Bus power
Main Bat charger
APU Bat charger
Miscellaneous
Can the Ground Handling bus be powered in-flight
No
Where does the Ground Handling Bus get it’s power from
APU Gen
GPU
How are the captains flight instruments powered if both Main AC buses fail
Via the HDG
Load shedding priority
Can power be restored
Galley Buses
Utility Buses
Individual equipment powered by Main AC buses
Yes, if load decreases or additional power source becomes available
What does the DC Hot Bat Bus power
Fire Extinguisher Bottles Fuel SOV's Clocks Rat Manual Deployment Parking Brake Valve
Each Main Bus Supplies power to
Associated Utility and Galley buses
Flight Instrument Transfer bus
Associated TRU
Ground Service Bus is normally powered by
The right main AC bus
Load shed sequence if system detects loads that exceed power available
Galley busses
Utility busses
Individual equipment
During Engine start what busses are shed
First engine
Second engine
During first engine all Galley and Utility busses shed
During the second engine start associated side Util and galley busses shed
Hot battery bus powers
Fire extinguisher bottles Fuel SOVs Rat Manual deployment Apu SOV Clocks Parking Brake Valve
