Electric System Flashcards
Generators (IDG) supply output
115 VAC (volt alternating current)
400 hz
40 KVA (kilo voltamperes)
IDG “FAULT” Lamp
High oil Temp or Low oil Pressure (HOTLOP)
How is the IDG/CSD cooled
by an air/oil heat exchanger that uses N1 air as a cooling medium.
IDG “DISC” lamp
Over temp or Over torque
What happens when IDG “DISC” is selected
Gear retracts from the engine accessory gearbox and can only be reconnected on the ground with the engine off.
Generator (GCU) output is tripped off and removed from the bus system when
Over/undervoltage
Over/under frequency
Overcurrent
Out of sequence
APU Generator output is
115 VAC
400 Hz
40 Kva
APU Generator is tripped off when:
Over/undervoltage
Over/under frequency
Overcurrent
Out of sequence
AC Bus priority (AC bus 1 and 2 are critical buses and need to remained powered at all times)
AC BUS 1:
GEN 1
APU GEN
GEN 2
External Power
AC Bus priority
AC BUS 2:
GEN 2
APU GEN
GEN 1
External Power
AC ESS BUS
Powered by AC BUS 1
Failure of AC BUS 1 will transfer to AC BUS 2 automatically or manually pressing “AC ESS XFER”
“AC ESS XFER”
Connects AC ESS BUS electrically to AC BUS 2
ADG output
115 VAC
400 Hz
15 kVA
When will the ADG deploy
AC BUS 1 and AC BUS 2 are unpowered
NO WOW (weight on wheels)
Minimum airspeed for ADG
135 kts
What will the ADG bus supply power to:
ESS BUS
3B Hydraulic Pump
FLAPS/SLATS ( half speed )
Stab trim channel 2
“PWR TXFR OVERRIDE” pushbutton can be pressed
When one or more electrical generators have come back online to power AC BUS 1 or AC BUS 2
DC Electrical system (TRUs, Batteries, Buses)
4 TRUs - 120 amps (28vdc)
2 batteries - Main & APU
9 buses
What do TRUs do
Turn AC (115vac) power to DC (28vdc) power
DC EMER (emergency) BUS powers
ENGINE FIRE extinguishers & SOV
APU FIRE extinguishers
APU Battery (aft equipment compartment)
24 VDC
43 Amp hours
Main Battery (nose avionics bay)
24VDC
17 Amp Hours
Batteries supply DC power to what busses
MAIN BATT DIR BUS
APU BATT DIR BUS
DC EMER BUS
DC BATT BUS
