Electrical Flashcards
How does the APU generator differ form the engine generators? Max KVA?
2 AC generators driven by each main engine through an integrated drive. APU generator driven directly by the APU. GAPCU controls the frequency and voltage of the APU generator and external power output.
90KVA.
What drives the emergency generator? Max KVA?
The blue hydraulic circuit driven by RAT.
5KVA.
What can supply AC ESS Bus?
- AC bus 1 (normal)
- AC bus 2 (bus 1 fails)
- Emergency generator
- Batteries (through static inverter)
On battery power only (in flight), which busses are supplied? And can the APU be started?
- Hot bus 1+2
- DC ESS bus (without DC ESS SHED)
- AC ESS bus (through static inverter w/o AC ESS SHED)
APU can be started, after 45secs.
What causes the RAT to auto-extend?
- Lost of AC bus 1 and 2.
- Airspeed >100kts.
If the RAT fails to auto-extend, what should you do?
Press the guarded MAN ON p/b to manually select RAT on the EMER ELEC PWR.
Which busses are supplied by the EMER GEN?
- AC ESS BUS
- DC ESS BUS
Via the ESS TR, including SHEDS
How is an IDG disconnected?
- Pressing the pb-sw disconnects the IDG from its drive shaft. Now more than 3secs.
- Do no disconnect the IDG when the engine is not running or windmilling.
What does the BUS TIE pushbutton do when selected OFF?
Both bust tie contractors open.
AVAIL (green) on the EXT PWR p/b means what?
- External power is plugged in
- External power parameters are normal
If TR 1 fails what supplies the DC ESS BUS?
ESS TR via AC ESS via AC 1 via GEN 1.
ESS TR via AC ESS via AC 1 via GEN 1.
How is GEN 1 switched OFF in the smoke CONFIG?
GEN 1 line contactor opens. The AC BUS 1 channel 1 is supplied from GEN 2 though bus tie contractors.
Safe way to get GEN 1 off, remains 2 fuel pumps, 1 each tank.
This is used for smoked drill.
From the Electrical SD, how can you tell that the batteries are being charged?
Battery contactor closed. Battery charging current >1A (in green)
What is the minimum battery volts at the start of the day?
25.5V
The battery volts check requires which switches to be OFF?
BAT 1+2