Electrical

Question 1

How does the APU generator differ form the engine generators? Max KVA?

Answer 1

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.

Question 2

What drives the emergency generator? Max KVA?

Answer 2

The blue hydraulic circuit driven by RAT.

5KVA.

Question 3

What can supply AC ESS Bus?

Answer 3

• AC bus 1 (normal)
• AC bus 2 (bus 1 fails)
• Emergency generator
• Batteries (through static inverter)

Question 4

On battery power only (in flight), which busses are supplied? And can the APU be started?

Answer 4

• 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.

Question 5

What causes the RAT to auto-extend?

Answer 5

• Lost of AC bus 1 and 2.

- Airspeed >100kts.

Question 6

If the RAT fails to auto-extend, what should you do?

Answer 6

Press the guarded MAN ON p/b to manually select RAT on the EMER ELEC PWR.

Question 7

Which busses are supplied by the EMER GEN?

Answer 7

• AC ESS BUS
• DC ESS BUS
  Via the ESS TR, including SHEDS

Question 8

How is an IDG disconnected?

Answer 8

• 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.

Question 9

What does the BUS TIE pushbutton do when selected OFF?

Answer 9

Both bust tie contractors open.

Question 10

AVAIL (green) on the EXT PWR p/b means what?

Answer 10

• External power is plugged in

- External power parameters are normal

Question 11

If TR 1 fails what supplies the DC ESS BUS?

Answer 11

ESS TR via AC ESS via AC 1 via GEN 1.

Question 12

ESS TR via AC ESS via AC 1 via GEN 1.

How is GEN 1 switched OFF in the smoke CONFIG?

Answer 12

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.

Question 13

From the Electrical SD, how can you tell that the batteries are being charged?

Answer 13

Battery contactor closed. Battery charging current >1A (in green)

Question 14

What is the minimum battery volts at the start of the day?

Answer 14

25.5V

Question 15

The battery volts check requires which switches to be OFF?

Answer 15

BAT 1+2

Question 16

How long does it take to charge the batteries.

Answer 16

20 mins