AC/DC electrical panel Flashcards
IDG 1 and 2 selector knob
Auto - allows the IDG contactor to close, connecting the IDG to the respective AC BUS automatically according to system logic
OFF - opens the IDG contactor isolating the IDG from the respective AC BUS
DISC - must be held for 1 second to mechanically disconnect IDG. Do not hold IDG knob to the DISC position for more
than three seconds.
Note : the amber light indicates which IDG to disconnect when IDG oil pressure drops below 140 psi ± 25 psi, or the IDG oil
temperature reaches 335°F ± 10°F (168°C ± 5°C), the EICAS message IDG 1 (2) OIL is displayed and an amber led illuminates near
the IDG selector knob on the overhead panel.
AC BUS TIES selector knob
AUTO - This position controls the operation of the BTCs,
according to system operational logic.
1 OPEN - open the Bus Tie Contactor (BTC) 1, segregating AC
BUS 1 from AC BUS 2.
2 OPEN - open the Bus Tie Contactor (BTC) 2, segregating AC
BUS 2 from AC BUS 1.
APU button
PUSH IN: allows automatic operation of the electrical system to connect the APU generator to the AC BUS Tie.
PUSH OUT: opens the APU generator contactor and isolates the APU generator from the AC BUS TIE. the APU generator is tripped off line and de-excited.
GPU button
PUSH IN: connects the AC GPU to the AC system, according to
the source priority.
PUSH OUT: isolates the AC GPU from the system.
AVAIL: illuminates inside the button when the AC GPU is
connected to the airplane and AC power quality
requirements (voltage/amperage/frequency) are
satisfied.
IN USE: illuminates inside the button when the AC GPU is
powering the airplane AC electrical system.
TRU ESS toggle switch
AUTO: allows automatic connection of the TRU ESS to the ESS BUS 3
OFF: isolates the TRU ESS from the ESS BUS 3.
TRU 1 AND TRU 2 TOGGLE SWITCH
AUTO: allows automatic connection of the TRU to the respective DC BUS
OFF: isolates the TRU from the respective DC BUS.
BATTERY 1 SELECTOR KNOB
ON: the battery is connected to the DC ESS BUS 1.
OFF: the battery supply power to the HOT BATT BUS 1 only and is no longer connected to the airplane electrical system.
DC BUS TIE TOGGLE SWITCH
AUTO: allows automatic operation of the electrical system.
OFF: opens all DC Tie contactors
BATTERY 2 SELECTOR KNOB
AUTO: connects BATT 2 to either the DC ESS BUS 2 or the APU START BUS automatically according to system logic
OFF: the battery supplies power to the HOT BATT BUS 2 only and is no longer connected to the airplane
electrical system.
