Elec Flashcards
AC voltage / frequency?
Engine Gen / APU apparent power?
Emer Gen apparent power?
DC voltage?
115/200V, 400Hz, constant frequency
90 kvA
5 kvA
DC 28 V
What do the GCUs / GAPCUS do?
What does a GCU (Emer Gen) do?
Generator Control Unit
Ground / APU Control Unit
- Control frequency / voltage
- Protect network via line contactor
Emer Gen GCU
* Controls speed / voltage
* Protects network via line contactor
* Controls start up
Which battery is the Static Inverter connected to?
How much apparent power supplied, to where?
What if BAT sw off?
When does it cut out?
Battery 1
1kvA to AC ESS BUS
Works regardless of battery switch position
Cuts out at 50kt (if BAT pb OFF)
Otherwise not
What is the current of the TRs?
What controls the TR line contactors?
200A DC
Each TR controls its own contactor
What is the battery capacity?
How are the battery contactors controlled?
23 Ah each
Each battery has its own Battery Charge Limiter (BGL) which controls the contactor
What are the three groups of monitored CBs? (Green caps)
Which CBs have red caps? Why?
- OVHD PNL
- ELEC BAY (L/R)
- REAR PNL
- JM / NR / SV / WZ
WTB have red caps to prevent reset
What is the difference between CLR and EMER CANC?
CLR: Clears all notifications from the same panel until CB reset
EMER CAN: clears all notifications for the rest of the flight
Can generators be connected in parallel?
No
In normal config, which busses does TR 1 power?
- DC BUS 1
- DC BAT BUS
- DC ESS BUS
Are the batteries continuously connected to the DC BAT BUS?
No- Battery Charge Limiters only close the contactors when:
- Battery voltage below 26.5 V
opens again when charge current below 4A- or 30 mins after that in flight - Loss of AC1+2 and under 100kt
- APU starting (until 95%)
Maintenance Bus ON: and aircraft network OFF
Which busses are the EXT PWR feeding?
AC GND/FLT BUS
DC GND/FLT BUS via TR2
Bypasses aircraft network.
Abnormal
What happens with the loss of one generator in flight?
Other GEN powers both sides. APU can take up the load of the failed Gen.
part of Galley automatically shed
Abnormal
What happens if a TR fails?
Why might a TR fail?
Other TR replaces the faulty one
(opposite DC fed via the bat bus)
ESS TR supplies DC ESS
It opens its own contactor due to
* overheat
* below minimum current
Abnormal
What happens if both TRs fail?
DC1, DC2, DC BAT busses lost
DC ESS fed by ESS TR (from AC ESS)
Abnormal
What happens if AC BUS 1 fails?
Which button might we need to press?
How long to wait until DC BUS 1 and DC BAT BUS come back online?
AC BUS 2 can supply AC ESS BUS (+ ESS TR + DC ESS)
via AC ESS FEED pb
(unless autoswitching installed)
DC BUS 2 supplies DC BAT and DC BUS 1 after 5 sec.
Abnormal
Dual Generator Fail
What are the conditions for the RAT dropping automatically?
What does the RAT power and how?
What happens when the RAT stalls?
If on batteries only, when can the APU be started?
ADIRS1 IAS over 100kt
AC BUS 1 + AC BUS 2 lost
RAT powers BLUE HYD, EMER GEN generates 5kvA power for AC ESS
also powers DC ESS via ESS TR
RAT stall- AC + DC SHED are shed
Below 50kt, AC ESS also shed (screens)
APU can only be started below 100kt on batteries
EMER ELEC
What is the difference between the
RAT&EMERGEN (EMER ELEC) pb
and the
RAT MAN ON (HYD) pb?
EMER GEN uses solenoid 1
HYD uses solenoid 2
GCU only connects to AC ESS / ESS TR
if EMER GEN pressed
OR AC1/2 OFF (>100kt)
Abnormal
What is the difference between EMER ELEC and Smoke Config?
Roughly how much equipment is shed? What does remain?
GEN 1 still powers the fuel pumps via the GEN 1 (fuel pumps upstream of the contactor)
Sheds around 75% of equipment
Overhead panel is what remains
Abnormal
What is the delay for APU start being available after dual generator fail?
45 sec
this is to prevent interference with EMER GEN coupling
What does the BAT 1(2) control?
Can they remain closed all the time on the ground?
What is still supplied when they are OFF?
What does a FAULT light mean?
The battery charge limiters
No, there is a limit to stop complete discharge on the ground when in AUTO
BAT BUS and HOT BUS
BCL fault- ECAM alert if charging current out of limits.
Why would the IDG fault light come on?
When will the IDG disconnect thermally?
- Oil outlet overheat (over 180º)
- IDG low pressure
ignored when N2 uner 14%
200º C automatic thermal disconnect
What happens when the generator switch is in auto?
Why would a generator pb show an amber fault light?
Why might you only get two reset attempts?
The generator field is energised, line contactor closed (if electrical parameters normal)
de-energised and contactor opened when OFF
- associated GCU tripped
- opening of the line contactor
In case of a differential fault causing the GPU to trip
What does the BUS TIE pb OFF mean?
When would one contactor be closed?
When would both contactors be closed?
Both bus ties are open
One closed when
* one engine generator supplies its own AC BUS
AND
* APU or external power supplies the other side
Both closed during single engine ops or APU / Ext Power powering everything
Why would AC ESS FEED pb show ALTN?
AC ESS supplied by AC 2
- needs to be pressed unless automatic switching installed
