Electrics Flashcards
What is the electrical system output in normal operation?
3 phase 90kva 115/200v 400hz AC System
28v DC battery system
In normal conditions how is power generated by the electrical system?
2 engine driven IDGs power AC BUS 1+2
AC BUS 1 powers AC ESS
AC BUSSES power respective DC BUSSES through a dedicated TR
DC BUS 1 powers DC ESS
As a result load on GEN 1 is generally 10% greater than load on GEN 2
What are the BUS TIE CONTACTORS?
They enable power to be transferred to the opposite electrical side, so side 1 can supply side 2 and vice versa. This is how the APU can power both sides of the electrical system.
In abnormal situations how is electricity generated & what is powered?
Emergency generator can supply limited electrical power. The RAT powers blue hydraulic system which drivers the Emer generator. The supply is 5kva AC which powers ACC ESS and DC ESS via the ESS TR. If the RAT stalls/fails EMER GEN transfers to batteries and static inverter
When will the RAT deploy automatically & what happens to the electrical system whilst no generators are online?
The RAT will deploy automatically following AC BUS 1+2 failure and >100kts. The RAT deployment and emergency generator coupling takes around 8 sec during which time the batteries are the only source of electrical power. Battery 1 powers AC ESS via static inverter. Battery 2 powers DC ESS. Once deployed the Emer gen takes over.
What are the limitations of the electrical system
100% load = 90 kva
What QRH checklists are there for the electrical system?
ELEC EMER CONFIG SUMMARY
ELEC EMER CONFIG SYSTEMS REMAININ
On what 3 occasions will the batteries connect to the battery BUS?
APU start on batteries
Recharge cycle (voltage below 26.5)
Flight on batteries only
What type of circuit breakers are there? Are there any that can’t be reset?
Monitored (Green)
Unmonitored (Black)
CBs with red sleeves can’t be reset (these are WTB)
Draw the electrical system in normal configuration
Go through electrical system reconfigurations on iPad ecam
What is emergency electrical config?
Emer elec config occurs following the loss of AC BUS 1+2. Electrical power is supplied by the Emer gen via the RAT. Only vital systems connected to AC ESS & DC ESS are powered. The Emer gen supplies AC power to the AC ESS BUS which in turn powers the DC ESS BUS via the ESS TR. Only CM1 can fly.
On the ground:
-Below 100kts DC BAT BUS auto connects to the batteries
-Below 50kts AC ESS BUS is automatically shed, leading to loss of all DUs
What is the electrical smoke configuration?
Same as Emer elec but you choose to enter this condition to protect the aircraft against undetermined electrical fire source. The main differences are
1) a fuel pump in each inner tank will remain operative so no need for gravity feeding
2) smoke config is intended as a temporary configuration, with normal electrical supply recovered before landing
What does the MAINTENANCE BUS ON switch do?
Means the AC and DC GND/FLT busses are powered for ground servicing without powering the whole aircraft.
Powers lights, sockets, refuelling panel etc
In flight, which generator has the higher load and why?
Generator 1 as it also powers the AC ESS BUS through AC BUS 1 and DC ESS BUS through DC BUS 2
