Electrical Flashcards
What is the ram air turbine used for?
Emergency generator inflight when both AC Buses 1 and 2 are not powered
What does the ram air turbine (RAT) supply power to?
The ESS Buses
What speed is required for the RAT to supply power to the AC/DC Buses
130 kt
Is there an altitude restriction on the RAT?
No altitude restriction
What comprises the DC electrical system?
- 2 batteries
* 3 TRUs
What supplies power to the APU START BUS during APU starts?
Battery #2
Describe the batteries
Two NiCd 22.8 VDC 27A batteries
Minimum battery temperature for starting the APU
-20°C
How are the batteries charged?
Constantly charged by any AC source through the TRUs, including the AC GPU and RAT
What are the IDG’s and APU rated at?
40 kVA, 115 VAC, 400 hz, three-phase
What is the source priority for powering the plane?
- Respective IDG
- APU generator
- GPU on ground
- Opposite IDG
What components are turned off via load shedding?
- Galleys
* Right windshield heating
What causes the amber IDG light on the overhead panel to illuminate?
- High oil temperature
* Low oil pressure
Can an IDG be reconnected if it was manually disconnected?
No
What is the purpose of the TRU’s?
Converts 115 VAC to 28 VDC
How long will the aircraft batteries last with no recharging?
10 minutes
What compromises the AC electrical system?
- Two IDG’s
- One APU
- One inverter
- One RAT
- One AC external power unit
How long after the RAT deploys will it take to power the AC ESS BUS?
After 8 seconds
What are the TRU’s rated at?
300 A
When will the BATT 1 (2) OVERTEMP EICAS message trigger?
Battery temperature reaches 70°C for at least 2 seconds
Minimum battery voltage to close the battery bus ties
18 volts
What is the RAT rated at?
15 kVA, 115 V AC, 400 hz, 3 phase
Which ACMP does the RAT power?
ACMP 3A
Which circuit breakers can only be reset by maintenance?
ICC remote thermal circuit breakers
What items are on the hot battery buses?
- Engine fire extinguisher
- Engine fuel SOV
- Engine hydraulic SOV
- Engine oil level
- Refuel panel
- DC service lights
What items are on the STBY AC BUS?
- Engine exciter 1A
* Engine exciter 2A
When is the RAT icon displayed on the electrical synoptic page?
When the RAT is deployed
What manages the electrical system?
- 4 integrated control centers (ICC)
* 2 secondary power distribution assemblies (SPDA)
What is the purpose of the ICC?
- Electrical control device
* Provides power distribution and protection for electrical loads
What is the purpose of SPDA?
•Distributes electrical loads to aircraft systems
