Electrics Flashcards
Which cockpit lighting is available during an emergency electrical situation?
Right side dome light main panel flood lights (left two columns only) and the standby compass light.
What is the function of the static inverter?
A static inverter transforms DC power from Battery 1 into one KVA of single-phase 115v/400hz AC power which is then supplied to part of the AC essential bus.
How many types of circuit breakers has the aircraft?
The aircraft has two types of C/Bs. Monitored (green): When off for more than one minute the C/B TRIPPED warning is triggered on the ECAM. Non-monitored (black).
Can you reconnect an IDG in flight?
No.
AC Power (115v) can be provided by which power sources?
Two engine generators one APU generator and one external power source.
What is the order of priority for the different generators?
Engines external power APU.
If the battery voltages are below the minimum how do you charge them?
I have to check that the BAT pushbuttons are on and switch the external power on.
When does the RAT automatically deploy?
Electrical power to both AC BUS #1 & #2 is lost and the aircraft speed is above 100 knots.
Is it possible to connect the engine driven generators in parallel?
No.
What does the blue EXT PWR ON light mean?
External power is supplying the aircraft electrical systems.
After IDG disconnection why do you get a GALLEY SHED indication in the SD?
It is a reminder that the main galley has been shed automatically following the loss of one generator.
If both engine generators are powering the system and one subsequently fails are any busses unpowered?
No but some loads are shed in both main galleys.
What is the purpose of the Ground and Auxiliary Control Power Unit (GAPCU)?
The GAPCU controls the frequency and voltage of the APU generator / external power output protects the network by controlling the emergency generator line contactor and controls the emergency generator start-up.
Where is the ground power connector?
The ground power connector is near to the nosewheel on the right side of the fuselage.
What occurs in case of a TR fault?
The contactor of each TR opens automatically in case of overheat or minimum current. The other TR automatically replaces the faulty one. The ESS TR supplies the DC ESS BUS.
Having started the APU with external power connected how can you get the APU generator to power the electrical system?
By pushing the EXT PWR Pb thus disconnecting the external power.
What powers the emergency generator?
The blue hydraulic via the RAT.
You enter a dark cockpit what action is necessary before checking the battery voltages?
You have to check that both batteries are off.
What is the purpose of the Transformer Rectifiers (TR’s)?
Two main Transformer Rectifiers TR 1 and TR 2 supply the aircrafts electrical system with up to 200 amperes of DC current. A third identical TR 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.
What are the main functions of the Generator Control Unit (GCU)?
Controls the frequency and voltage of the generator output and protect the network by controlling the associated generator line contactor (GLC).
Which bus supplies the AC ESS BUS?
The AC ESS BUS is normally supplied from the AC BUS 1 it may be supplied be AC BUS 2 through the AS ESS FEED pb.
What is the capacity of the main batteries?
Two main batteries have a capacity of 23 ampere-hours each.
BAT 1 (2) pb (ELEC Panel)
- Auto
- OFF
- FAULT Light
Auto:
The battery charge limiter automatically closes/opens the corresponding battery line contactor. The batteries are connected to the DC BAT BUS in the following cases:
• APU starting until N < 95%. (limited to 3 min when the emergency generator is running)
• Battery voltage < 26.5 V (battery charge).
• Loss of AC BUS 1&2 when below 100 knots (EMER GEN not supplying).
OFF:
The battery charge limiter is not operating: the battery line contactor is open.
FAULT Light:
The charging current for the corresponding battery is outside limits. In this case the battery contactor opens.
IDG 1 (2) pb (guarded) (ELEC Panel)
- FAULT Light
Switch spring loaded out.
Do not hold > 3 sec.
Do not disconnect when engine not windmilling.
FAULT Light:
- IDG oil outlet overheats (above 185°C), or
- IDG oil pressure is low (inhibited at low engine speed: N2 below 14 %)
LT extinguishes when the IDG is disconnected.
GEN 1 (2) pb (ELEC Panel)
- ON
- OFF
- FAULT Light
ON:
Generator line contactor closes if electrical parameters are normal.
OFF:
Generator line contactors open. The fault circuit is reset.
FAULT Light:
- The generator control unit (GCU) trips it.
- Line Contactor open with the GEN pb selected ON
APU GEN pb (ELEC Panel) - ON - OFF - FAULT Light
ON:
Line contactor closes if parameters are normal and the EXT PWR line contactor is open.
OFF: Line contactor opens. The fault circuit is reset.
FAULT LT:
- The generator control unit (GCU) trips it.
- Opening of the line contactor (except if the APU GEN pb is selected OFF). The light is inhibited when APU speed is too low or if the APU GEN line contactor opens after EXT PWR or ENG GEN takes over.
BUS TIE pb
(ELEC Panel)
- AUTO
- OFF
AUTO:
The bus tie contactors (BTCs) open or close automatically.
OFF:
Both bus tie contactors open.
AC ESS FEED pb
(ELEC Panel)
- NORMAL
- ALTN
- FAULT Light
NORMAL:
The AC ESS BUS is supplied from AC BUS 1. It is automatically supplied by AC BUS 2, when AC BUS 1 is lost.
ALTN:
Comes on when manually selected. The AC ESS BUS is supplied from AC BUS 2.
FAULT LT:
AC ESS BUS is not supplied.
GALY & CAB pb
(ELEC Panel)
- AUTO
- OFF
- FAULT Light
AUTO:
Main galley, secondary galley and in-seat power supply are supplied.
The main galley and in-seat power supply are shed automatically when:
- In flight: only one generator is operating.
- On the ground: only one engine generator is operating. (Except APU or EXT power.)
OFF:
The main galley, secondary galley and in-seat power supply are not supplied.
FAULT LT:
When the load on any generator is more than 100% of rated output.
EXT PWR pb
(ELEC Panel)
- AVAIL Light
- ON Light
AVAIL light comes on green if:
- External power is plugged in, and
- External power parameters are normal.
Pressed momentarily:
Opens/Closes the external power line contactor. The ON light comes on blue when closed.
COMMERCIAL pb
(ELEC Panel)
- ON
- OFF
ON: All aircraft commercial electrical loads are supplied: - Cabin and cargo lights - Water and toilet system - Drain mast ice protection - Galley - Passengers' entertainment - Semi-automatic cargo loading (if installed)
OFF:
Switches off all aircraft commercial electrical loads.
MAN ON pb (guarded)
(EMER ELEC PWR panel)
- AUTO
- Pressed
AUTO:
RAT deploys when
- AC BUS 1&2 is not electrically supplied and speed >100 knots.
Pressed:
Manual RAT extension.
RAT EMER GEN
(EMER ELEC PWR panel)
- FAULT Light
FAULT LT:
This light comes on red if the emergency generator is not supplying power when AC BUS 1&2 are not powered.
EMER GEN TEST pb (guarded)
(EMER ELEC PWR panel)
- Pressed and held
Pressed and held:
• If AC NORMAL BUSES are supplied:
- The EMER GEN is driven hydraulically if the blue electric pump is running.
The AC ESS BUS and the DC ESS BUS are connected to the emergency generator.
(The DC ESS SHED and AC ESS SHED buses are not powered.)
- ECAM displays the ELEC page automatically (only on the ground).
• If only the batteries supply the aircraft:
- The static inverter powers the AC ESS BUS.
GEN 1 LINE
(EMER ELEC PWR panel)
- OFF
- SMOKE LT
OFF:
GEN 1 line contactor opens. AC BUS 1 is supplied from GEN 2 through bus tie contactors. This is used for the avionics smoke condition to isolate GEN 1, but it continues to power one fuel pump in each wing tank.
Smoke LT:
Avionics smoke
What powers the emergency generator?
Blue Hydraulic power from the RAT
What is the power source for the FADEC?
- The system has its own alternator making it independent of the aircraft electrical system when N2 is above a set value
- If this alternator fails, the FADEC automatically switches to aircraft electrical power
What is the purpose of the static inverter?
To provide AC power to the AC ESS bus from the battery when the EMG GEN is not online when in Emergency Electrical configuration.
What is the priority sequence for electrical power?
- Generators (ENG)
- EXT PWR (Manually selected)
- APU Gen
- RAT Emer Gen
- Batteries
When performing the PRELIMINARY FLIGHT DECK PREPARATION, what is the minimum battery voltage?
25.5 Volts
What do you do if it is below 25.5V?
Select battery switches ON with EXT PWR on aircraft
Will the batteries completely drain if you leave the BAT switches in AUTO after AC power is removed?
No. Battery cut-off logic prevents complete discharge when the aircraft is on the ground and un-powered - 22 VDC
How is the BATTERY BUS normally powered?
DC BUS 1 through a DC tie contactor
When is the battery check performed?
During the FLIGHT DECK PREPARATION check of the ELEC Panel
What does a Bat Fault light indicate?
Battery charging current is outside limits (BAT contactor opens)
What are the 3 times the batteries are connected to the BATTERY BUS?
- APU Start
- Battery charging
- AC BUS 1&2 not powered and airspeed below 100 knots
What does the ON BAT light indicate?
It is illuminated amber if one or more IRs is supplied by the aircraft battery.
Also illuminates briefly during the beginning of a full alignment.
How long will each ADIRU stay on battery power?
ADIRS 2&3 will remain on battery power for 5 minutes to hold alignment until a generator can be restored.
ADIRU 1 (ADIRU 3 if captain selected ATT HDG CAPT 3) will remain on battery power until generator power is restored or the batteries fail.
When performing the FLIGHT DECK PREPARATION, what are we looking for on the ELEC panel BAT check
- ECAM ELEC page - select
- Bat 1&2 - OFF then ON
- Check BATT charge current is < 60 amps and decreasing within 10 seconds
What does each of the DMCs normally supply?
- DMC1: Capt PFD, ND, Upper ECAM DU
- DMC2: F/O PFD, ND, Lower ECAM DU
- DMC3: Backup
How is the IDG (Integrated Drive Generator) cooled?
By fuel from the HP fuel pump drawn in from the fuel manifold and then returned to its respective outer tank. When full, the outer tank spills over to the inner tank.
If the IDG return fuel fills the wing tanks, what occurs?
The center tank pumps turn off until the wing tank quantity reduces by 1100 lbs
With full wing fuel what prevents the IDG fuel from overfilling the wings?
Separate full level switches
What does IDG stand for?
Integrated Drive Generator
What is the function of the IDG?
Converts variable engine speed to constant speed for optimum generator operation
What does an IDG FAULT light indicate?
- Oil pressure low (inhibited when N2 <14
- Oil outlet temperature overheat
- Light is inhibited when IDG is disconnected
What precautions must you take when disconnecting an IDG?
- Do not disconnect when engine is not operating or windmilling
- Do not hold button longer than 3 seconds
How can an IDG be reset?
On the ground by maintenance
What is the max continuous load rating of the engine and APU generators?
90 kVA
What does the APU GEN FAULT light indicate?
The generator line contactor is open because of a fault detected by the GCU
When is the APU GEN FAULT light inhibited?
- APU speed to low
- Line contactor OPEN after EXT PWR or ENG GEN takes over
What is the function of the BUS TIE in the AUTO position?
Allows the BUS TIE CONTACTORS to open and close automatically to maintain power to both AC BUS 1&2:
- Allows a single source to power the entire system
- Allows connection of the APU GEN or EXT PWR to the system
- Inhibits multiple sources to connect simultaneously
How does the GALLEY pushbutton work in AUTO?
Sheds main galley and in-seat power supply if:
- Only 1 generator (APU or ENG) is available in FLIGHT, OR
- Only 1 ENG generator is available on the ground
What is the function of the AC ESS FEED pushbutton in the normal position?
Allow AC BUS 1 to power the AC ESS BUS
How is AC ESS FEED transferred from AC BUS 1 to AC BUS 2?
Manually by selecting ALTN on the AC ESS FEED pushbutton
What does the AC ESS FEED pushbutton white ALTN light indicate?
AC BUS 2 is powering the AC ESS BUS
What lights illuminate when the DC ESS SHED BUS fails?
- Floor proximity emergency escape path marking system
- Overhead emergency lighting
- EXIT signs
What buses are powered by the emergency generator?
- AC ESS and AC SHED
- DC ESS and DC SHED
What does the RAT & EMER GEN red fault light indicate?
- Loss of AC BUS 1 & 2,
- Airspeed above 100 Kts, and
- Emergency generator not supplying AC power
What is the function of the RAT & EMER GEN pushbutton?
- AUTO- RAT will automatically extend if AC BUS 1 & 2 are not powered and airspeed is >100 Kts
- MAN- Extend the RAT at any time
What happens when you push the GEN 1 LINE pushbutton
- GEN 1 Line Contactor opens and the white OFF light illuminates
- AC BUS 1 is powered by GEN 2 through the BUS TIE CONTACTOR
- GEN 1 continues to power 1 fuel pump in each wing tank
What does the amber “FAULT” light in the GALLEY pushbutton indicate?
At least 1 generator load is above 100% rated output
What does a “FAULT” on the ENG GEN pushbutton indicate?
- A Fault is detected by the GCU
-Overload
-Over/under voltage
-Differential fault (short)
And/or:
-The generator line contactor is open
When is it normal to see the ENG GEN FAULT light illuminated?
Prior to engine start because the GEN is selected ON by the line contactor is open - normal condition
What does the red “FAULT” light on the RAT & EMER GEN push button indicate?
Normal AC is lost and the emergency generator is not supplying power
When should the red “FAULT” light on the RAT & EMER GEN pushbutton be expected?
During the 8 seconds RAT deployment and power up
What is the output of the Emergency Generator?
5 kVA
Do pilots ever use the EMER GEN TEST pushbutton?
No. Maintenance function only
When would you select the GEN 1 LINE pushbutton?
Smoke procedures
How long will it take to charge the batteries?
20 minutes
What is the output of the static inverter?
1 kVA
Is there another way to deploy the RAT?
Yes, RAT MAN ON from the HYD panel
