Electrical Flashcards
The electrical power system consists of
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.
In normal configuration, the electrical power system provides AC power. The electrical power system is constituted of
2 engine generators and 1 APU generator.
In the event that normal AC power is not available, an ___ can provide AC power.
emergency generator
In the event that all AC power is not available, the electrical power system can
invert DC power from the batteries into AC power.
GENERATION OF AC ELECTRICAL POWER
4 items
- ENGINE DRIVEN GENERATORS x2
- APU GENERATOR AND EXTERNAL POWER
- EMERGENCY GENERATOR
- STATIC INVERTER
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
90 KVA of three phase 115/200 V 400 Hz power.
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
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.
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
5 KVA of three-phase 115 and 200 V 400 Hz power.
STATIC INVERTER
A static inverter transforms DC power from Battery 1 into
1 KVA of single-phase 115 V 400 Hz AC power, which is then supplied to part of the AC essential bus.
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.
above
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.
below
GENERATION OF DC ELECTRICAL POWER
2 items
- TRANSFORMER RECTIFIERS (TRS) x2 & ESS TR x1
- BATTERIES x2
TRANSFORMER RECTIFIERS (TRS)
Two main transformer rectifiers, TR 1 and TR 2, supply the aircraft’s electrical system, with up to
200 A of DC current.
A third (identical) Transformer Rectifier, the ESS TR, can power the essential DC circuit from the emergency generator, if
the engine and APU generators all fail, or if TR 1 or TR 2 fails.
BATTERIES
Two main batteries, each with a normal capacity of
23 Ah, are permanently connected to the two hot buses.
Each battery has an associated Battery Charge Limiter (BCL).
The BCL monitors
battery charging and controls its battery contactor.
CIRCUIT BREAKERS (C/BS)
The aircraft has two types of C/Bs:
‐ Monitored (green): When out for more than 1 min, the C/B TRIPPED warning is triggered on the
ECAM.
‐ Non-monitored (black).
___ C/Bs have red caps on them to prevent them from being reset.
The Wing Tip Brake (WTB)
The C/B TRIPPED warning on the ECAM indicates the location of the affected C/B. The following panels are monitored:
OVHD PNL, L(R) ELEC BAY, REAR PNL J-M or N-R or S-V or W-Z.
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
the remainder of the flight,
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
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.
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.
- APU generator and over external power
- APU generator
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.
AC BUS 1
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.
DC BUS 1, DC BAT BUS, and DC ESS BUS
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.
MAINT BUS
Either the APU generator, or external power, may supply the complete system.
EXTERNAL POWER ONLY :
APU GEN ONLY :
APU GEN + GEN 2 :
- supply the complete system
- supply the complete system
- APU GEN supplies AC1, TR1, DC1 & GEN 2 supplies AC2, TR2, DC2 (Refer FCOM diagram)
FAILURE OF ONE ENGINE GENERATOR
The system automatically replaces the failed generator, with the :
‐ APU GEN, if available, or
‐ Other engine generator.
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.
the AC ESS FEED pb. This is done automatically with the AC ESS FEED Auto Switching .
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.
ESS TR
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 ___ .
ESS TR
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.
100 kt
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
the batteries and static inverter, and the system automatically sheds the AC SHED ESS and DC SHED ESS buses.
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.
DC BAT BUS / AC ESS BUS
EMERGENCY GENERATION AFTER LOSS OF ALL MAIN GENERATORS
During RAT extension and emergency generator coupling (about 8 s), the ___ power the emergency generation network.
batteries
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 ___
below 100 kt.
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
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).
