Elec

Question 1

Normal AC network (115 V AC)

Answer 1

4 engine gens
2 APU gens
Up to 4 ground based power units

Each Engine Gen feeds it’s own AC BUS (Gen 1 - AC BUS 1). If a Gen fails, its AC BUS can be supplied via other Gens

At least 2 Engine Gens required to feed all buses

AC BUS 1 supplies AC ESS (can also be fed by AC BUS 4) which supplies AC EMER BUS

Engine Gens provide variable freq AC, APU gens provide constant 400 Hz freq

Question 2

Normal DC

Answer 2

4 Batts: Bat 1, Bat 2, Ess Bat, APU Bat

Batts can’t be disconnected from their respective HOT BUS

4 TRs:
TR1 (off AC Bus 2, feeds DC Bus 1 and Bat 1)

Ess TR (Off AC ESS Bus, feeds DC ESS Bus and ESS Bat)

TR2 (Off AC BUs 3, feeds DC Bus 2 and Bat 2)

APU TR (Off AC Bus 4, feeds APU DC Bus and APU Bat)

Question 3

Emer network

Answer 3

RAT and Bats (via static inverter) serve network

RAT automatically extends if AC BUS 1, 2, 3 and 4 lost

So Rat supplies AC ESS, which feeds AC EMER and ESS TR (therefore DC ESS

Question 4

ENMUs (Electrical Network Management Units)

ELMU (Electrical Load Management unit)

Answer 4

ENMU 1 and 2 control the network by:
Connecting/disconnecting AC and DC power sources
Re-configuring the network
Sending appropriate messages to ECAM

ELMU: Auto load shedding of AC commercial loads to ensure optimal usage of power