Systems - Electrical

Question 1

What causes the system to revert to the emergency electrical configuration?

Answer 1

Loss of power to AC BUSes 1 & 2

Question 2

When the emergency electrical configuration is triggered, will the RAT deploy?

Answer 2

Yes it will deploy automatically, this takes 5 - 10 seconds, during which the batteries are the only source of power.

Question 3

What does the emergency generator power?

Answer 3

The AC ESS bus, AC ESS SHED bus, and through the ESS TR the DC ESS bus and EC ESS SHED bus.

Question 4

Does the emergency generator (when active) charge the batteries?

Answer 4

No, because it is not connected to the DC BAT bus

Question 5

When the emergency elec configuration is triggered, how long is APU start inhibited for to conserve power?

Answer 5

45 seconds. After which a start is available, but not recommended as a failed start will drastically drain the batteries.

Question 6

In the emergency elec config, with the RAT deployed and the emergency gen online, what happens on landing when IAS drops below 100kt?

Answer 6

The emergency generator automatically disconnects from the electrical network, the batteries are then the sole source of power for the AC and DC ESS Busses (will stall at 125kt, min rat is 140kt)

Question 7

What is powered on battery power only?

Answer 7

BAT 1 powers:
*AC ESS bus (through static inverter and static inverter bus)

BAT 2 powers:
*DC ESS bus

Both HOT BAT busses are always powered, and SHED busses are shed.

Question 8

In the emergency electrical config, how much time do you have on batteries ONLY?

Answer 8

Approximately 25 minutes, this can be increased to 30 minutes by promptly actioning QRH procedures to reduce load.