TR 1
End the Electrical System Review
TR 3 Backup Relay
Electrical System General Description
AC Transfer Bus 2
IDG 1
IDG 2
APU
TR 3
TR 2
External Power
BTB
BTB
External Power Breaker
APU Breaker
Click on the labels for detailed information.
Galley Bus C and D
Galley Bus A and B
Main Bus 2
Main Bus 1
AC Transfer Bus 1
Cross Bus Tie Relay
Ground Service Bus 1
Ground Service Bus 2
DC Bus 1
DC Bus 2
DC Standby Bus
Ground Service Relay
AC Standby Bus
Battery Bus
Hot Battery Bus
Switched Hot Battery Bus
Inverter
Battery Charger
Battery
Auxiliary Battery
An auxiliary battery and
charger is optional and
may not be present.
Aux Charger
To APU Starter
From FA Ground Service Switch
Ground Service Relay
To Ground Service
Bus 2 Relay
Simplified Electrical System Schematic
AC Power Distribution and Bus Switching
and return to previous module.