Electrics

Question 1

How is DC power generated?

Answer 1

Two transformer rectifiers one from each AC BUS supply up to 200A of DC current.
A third TR (ESS TR) can power DC circuit from the emergency generator.
Batteries connected permanently to two hot buses.

Question 2

Which CB’s are monitored?

Answer 2

Green monitored, black not.

Be aware that other tripped Cb’s may not cause additional warnings.

Question 3

Minimum battery voltage before recharge required.

Answer 3

25.5V

Question 4

How is the AC generated?

Answer 4

2 engine driven generators, 90kVa 115/200V 400 hz
APU gen and external power
Emergency generator 5 kva 115/200V 400hz
Static inverter transforms from battery 1, 1kva 115/200V to AC ESS BUS.

Question 5

Can you reengage a C/B in flight which has tripped by itself?

Which C/Bs can you never re-engage?

Answer 5

Green c/b’s monitored, black not.

In flight, do not reengage a C/B that has tripped by itself, unless the Captain judges it necessary to do so for the safe continuation of the flight. This procedure should be adopted only as a last resort, and only one reengagement should be attempted.
On ground, do not reengage the C/B of the fuel pump(s) of any tank. For all other C/Bs, if the flight crew coordinates the action with maintenance, the flight crew may reengage a tripped C/B, provided that the cause of the tripped C/B is identified.
Also the wing tip brakes have red caps to stop them being reset.