Electrical

Question 1

The electrical power system consists of

Answer 1

a three-phase 115/200 V 400 Hz constant-frequency AC system and a 28 V DC system. Electrical transients are acceptable for equipment. Commercial supply has secondary priority.

Question 2

In normal configuration, the electrical power system provides AC power. The electrical power system is constituted of

Answer 2

2 engine generators and 1 APU generator.

Question 3

In the event that normal AC power is not available, an ___ can provide AC power.

Answer 3

emergency generator

Question 4

In the event that all AC power is not available, the electrical power system can

Answer 4

invert DC power from the batteries into AC power.

Question 5

GENERATION OF AC ELECTRICAL POWER
4 items

Answer 5

• ENGINE DRIVEN GENERATORS x2
• APU GENERATOR AND EXTERNAL POWER
• EMERGENCY GENERATOR
• STATIC INVERTER

Question 6

ENGINE – DRIVEN GENERATORS
Two AC generators (GEN 1, GEN 2), one driven by each main engine through an integrated drive, supply aircraft electrical power. Each generator can supply up to

Answer 6

90 KVA of three phase 115/200 V 400 Hz power.

Question 7

APU GENERATOR AND EXTERNAL POWER
A third generator (APU GEN), driven directly by the APU and producing the same output as each main engine generator, can replace

Answer 7

either or both main engine generators at any time.
A ground power connector near the nosewheel allows ground power to be supplied to all busbars.

Question 8

EMERGENCY GENERATOR
The blue hydraulic circuit drives an emergency generator that automatically supplies emergency AC power to the aircraft electrical system, if all main generators fail. This generator supplies

Answer 8

5 KVA of three-phase 115 and 200 V 400 Hz power.

Question 9

STATIC INVERTER
A static inverter transforms DC power from Battery 1 into

Answer 9

1 KVA of single-phase 115 V 400 Hz AC power, which is then supplied to part of the AC essential bus.

Question 10

When the aircraft speed is ___ 50 kt , the inverter is automatically activated, if only the batteries are supplying electrical power to the aircraft, regardless of the BAT 1 and BAT 2 pushbutton positions.

Answer 10

above

Question 11

When the aircraft speed is ___ 50 kt, the inverter is activated, if only the batteries are supplying electrical power to the aircraft, and both BAT 1 and BAT 2 pushbuttons are on.

Answer 11

below

Question 12

GENERATION OF DC ELECTRICAL POWER
2 items

Answer 12

• TRANSFORMER RECTIFIERS (TRS) x2 & ESS TR x1
• BATTERIES x2

Question 13

TRANSFORMER RECTIFIERS (TRS)
Two main transformer rectifiers, TR 1 and TR 2, supply the aircraft’s electrical system, with up to

Answer 13

200 A of DC current.

Question 14

A third (identical) Transformer Rectifier, the ESS TR, can power the essential DC circuit from the emergency generator, if

Answer 14

the engine and APU generators all fail, or if TR 1 or TR 2 fails.

Question 15

BATTERIES
Two main batteries, each with a normal capacity of

Answer 15

23 Ah, are permanently connected to the two hot buses.

Question 16

Each battery has an associated Battery Charge Limiter (BCL).
The BCL monitors

Answer 16

battery charging and controls its battery contactor.

Question 17

CIRCUIT BREAKERS (C/BS)
The aircraft has two types of C/Bs:

Answer 17

‐ Monitored (green): When out for more than 1 min, the C/B TRIPPED warning is triggered on the
ECAM.
‐ Non-monitored (black).

Question 18

___ C/Bs have red caps on them to prevent them from being reset.

Answer 18

The Wing Tip Brake (WTB)

Question 19

The C/B TRIPPED warning on the ECAM indicates the location of the affected C/B. The following panels are monitored:

Answer 19

OVHD PNL, L(R) ELEC BAY, REAR PNL J-M or N-R or S-V or W-Z.

Question 20

The flight crew can clear the ECAM C/B TRIPPED caution by pressing:
‐ The EMER CANC pb: When pressed, this pushbutton clears and inhibits the ECAM C/B TRIPPED caution for

Answer 20

the remainder of the flight,

Question 21

The flight crew can clear the ECAM C/B TRIPPED caution by pressing:
‐ The CLR pb: When pressed, this pushbutton only clears the ECAM C/B TRIPPED
caution. If the C/B remains pulled, any additional tripped circuit breakers on the same panel will

Answer 21

not be detected, and the ECAM will not trigger the caution. However, if the C/B is pushed, any additional tripped circuit breakers will be detected, and the ECAM will trigger the caution again.

Question 22

GEN 1 and 2 when operating have priority over the ___ . External power has priority over the ___ when the EXT PWR pb switch is ON. The APU generator or external power can supply the entire network.

Answer 22

• APU generator and over external power
• APU generator

Question 23

Each engine-driven generator supplies its associated AC BUS (1 and 2) via its generator line contactor (GLC 1 and GLC 2).
___ normally supplies the AC ESS BUS via a contactor.

Answer 23

AC BUS 1

Question 24

TR 1 normally supplies ___ .
TR 2 normally supplies DC BUS 2.
The two batteries are connected to the DC BAT BUS, if they need charging. When they are fully charged, the battery charge limiter disconnects them.

Answer 24

DC BUS 1, DC BAT BUS, and DC ESS BUS

Question 25

On ground, when only ground services are required, external power can supply the AC and DC GND/FLT BUSES directly without supplying the entire aircraft network.
Personnel select this configuration with the ___ switch in the forward entrance area.

Answer 25

MAINT BUS

Question 26

Either the APU generator, or external power, may supply the complete system.
EXTERNAL POWER ONLY :
APU GEN ONLY :
APU GEN + GEN 2 :

Answer 26

• supply the complete system
• supply the complete system
• APU GEN supplies AC1, TR1, DC1 & GEN 2 supplies AC2, TR2, DC2 (Refer FCOM diagram)

Question 27

FAILURE OF ONE ENGINE GENERATOR
The system automatically replaces the failed generator, with the :

Answer 27

‐ APU GEN, if available, or
‐ Other engine generator.

Question 28

FAILURE OF AC BUS 1
‐ AC BUS 2 can supply AC ESS BUS, and ESS TR can supply DC ESS BUS, both via ___
‐ DC BUS 2 supplies DC BUS 1 and DC BAT BUS automatically after 5 s.

Answer 28

the AC ESS FEED pb. This is done automatically with the AC ESS FEED Auto Switching  .

Question 29

FAILURE OF ONE TR
The contactor of each TR opens automatically, in case of :
‐ Overheat
‐ Minimum current
The other TR automatically replaces the faulty one. The ___ supplies the DC ESS BUS.

Answer 29

ESS TR

Question 30

FAILURE OF TR 1 AND TR 2
If TR 1 and TR 2 are lost, DC BUS 1, DC BUS 2, and DC BAT BUS are lost. The DC ESS BUS is supplied by the ___ .

Answer 30

ESS TR

Question 31

EMERGENCY GENERATION AFTER LOSS OF ALL MAIN GENERATORS
If both AC BUS 1 and AC BUS 2 are lost and the aircraft speed is above ___ , the Ram Air Turbine (RAT) extends automatically. This powers the blue hydraulic system, which drives the emergency generator by means of a hydraulic motor. This generator supplies the AC ESS BUS, and the DC ESS BUS via the ESS TR.

Answer 31

100 kt

Question 32

EMERGENCY GENERATION AFTER LOSS OF ALL MAIN GENERATORS
If the RAT stalls, or if the aircraft is on the ground with a speed below 100 kt, the emergency generator has nothing to drive it. The emergency generation network automatically transfers to

Answer 32

the batteries and static inverter, and the system automatically sheds the AC SHED ESS and DC SHED ESS buses.

Question 33

EMERGENCY GENERATION AFTER LOSS OF ALL MAIN GENERATORS
When the aircraft is on ground :
‐ Below 100 kt, ___ is automatically connected to the batteries.
‐ Below 50 kt, ___ is automatically shed, leading to the loss of all display units.

Answer 33

DC BAT BUS / AC ESS BUS

Question 34

EMERGENCY GENERATION AFTER LOSS OF ALL MAIN GENERATORS
During RAT extension and emergency generator coupling (about 8 s), the ___ power the emergency generation network.

Answer 34

batteries

Question 35

EMERGENCY GENERATION AFTER LOSS OF ALL MAIN GENERATORS
On ground, if only the batteries are powering the emergency generation network, APU start is only available when the speed is ___

Answer 35

below 100 kt.

Question 36

SMOKE CONFIGURATION
In this configuration the main busbars are shed. The electrical distribution is the same as it is in
the emergency electrical configuration (loss of main generators), except the fact that in smoke configuration the fuel pumps are

Answer 36

connected upstream of the GEN 1 line connector.

The procedure sheds approximately 75 % of electrical equipment. All equipment that remains powered is supplied via the circuit breakers on the overhead panel (except for equipment supplied by hot buses).