Flashcards in Electrical Deck (16)
How does the APU generator differ form the engine generators? Max KVA?
APU generator output is identical to that of the engine-driven generators.
What drives the emergency generator? Max KVA?
The RAT pressurises the blue hydraulic system which drives the hydraulically-driven emergency generator.
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 start is not available for 45s after the loss of both engine generators.
On Batteries only, the APU can only be started below 25,000ft.
What causes the RAT to auto-extend?
- Loss 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.
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. No more than 3secs.
- Do not disconnect the IDG when the engine is not running or windmilling.
What does the BUS TIE pushbutton do when selected OFF?
Both bus 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.
How is GEN 1 switched OFF in the smoke CONFIG?
GEN 1 line contactor opens. This disconnects generator 1 from everything except for 1 fuel pump in 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 (indicated by a green arrow)
What is the minimum battery volts at the start of the day?
The battery volts check requires which switches to be OFF?