ELECTRICAL POWER – CONTROLS
1 BUS TIE switch
• ON ............... BUS TIE contactor is forced to close: MAIN
BUS 1 and MAIN BUS 2 are interconnected
• AUTO .......... (normal position) BUS TIE contactor operates
automatically according to the control logic
• RESET ........ (spring-loaded momentary position) resets the
latching protection logic that inhibits BUS TIE
contactor operation when overcurrent is
detected by the GCU
2 GEN 1 switch
• OFF ............. disables or shuts down Generator 1 and
resets latched functions in the GCU 1
• ON ............... requests GCU 1 to control Generator 1 to be
on-line
3 GEN 2 switch
• OFF ............. disables or shuts down the Generator 2 and
resets latched functions in the GCU 2
• ON ............... requests GCU 2 to control Generator 2 to be
on-line
4 BATTERY MASTER switch
• OFF ............ disconnects batteries (MAIN and AUX) from all
bus bars
• ON .............. • connects MAIN and AUX batteries to ESS
buses
• enables the BATTERY MAIN and
BATTERY AUX switches
5 BATTERY MAIN switch
• OFF ............ disconnects the MAIN battery from MAIN BUS
1
• ON ............. if BATTERY MASTER switch is at ON and not
otherwise inhibited, connects the MAIN battery
to the MAIN BUS 1
6 BATTERY AUX switch
• OFF ............ disconnects the AUX battery from MAIN BUS 2
• ON ............. if BATTERY MASTER switch is at ON and not
otherwise inhibited, connects the AUX battery
to the MAIN BUS 2
7 EXT PWR switch (allows the pilot to control the application of external
power source)
• OFF ................ disconnects the external power from aircraft
distribution bus bars
• ON .................. connects the external power to the aircraft
distribution bus bars
8 Red gang bar
• Moved
backward ........
cuts off all aircraft electrical power sources
at the same time (GEN 1, GEN 2 and
BATTERY MASTER switches are moved to
OFF all together)