Electrical Flashcards
What makes up the DC system
- 2 NiCd batteries
- 3 Transformer Rectifier Units (TRUs)
- 1 DC external input
What makes up the AC system
- 2 IDGs
- 1 APU generator
- 1 Inverter
- 1 Ram Air Turbine (RAT)
- 1 AC external power unit
What are the IDGs and APU generator rated at
40 kVa, 115 V, 400Hz, 3 phase
What does the static inverter do
It converts 28v DC to 115v AC to power the STANDBY AC BUS when an AC power source is not available
What type of power is produced by the RAT
15kVa, 115v AC, 400Hz, 3 phase
When is the RAT automatically deployed
Whenever AC power sources are not powering AC buses
How long after deployment will the RAT begin to supply power
8 sec
Which bus does the RAT power when in use
AC ESS BUS
During the timespan prior to RAT supplying power, what happens in order to maintain power
The batteries power the DC ESS BUS and the STANDBY AC BUS
Which hydraulic pump does the RAT power
ACMP 3A
Below what speed will the RAT be unable to continue to supply sufficient power
130kts
What happens if airspeed drops below that required to utilize the RAT
The batteries power the DC ESS BUSSES and the STANDBY AC BUS through the static inverter
What is a DC GPU used solely for
Powering the APU START BUS on the ground
What are the TRUs rated to
300A
What does TRU1 power
DC BUS1, DC ESS BUS1, DC GND SVC BUS, HOT BATT BUS 1, battery #1 charging
What does TRU2 power
DC BUS 2, DC ESS BUS 2, HOT BATT BUS 2 and battery #2 charging
What does the ESS TRU power
DC ESS BUS 3
What kind of power do the batteries supply
22.8VDC, 27A
When is the BATT 1 (2) OVERTEMP warning triggered
When the battery temp reaches 70C for 2 secs
When do you use a DC GPU
When the battery is no longer available or the Battery #2 is below -20C
What do the Integrated Control Centers (ICCs) do
Provide power distribution and protection for the airplane electrical loads, the secondary power distribution assemblies (SPDAs) and the circuit breakers
How many ICCs does the plane have
4
• Left Integrated Control Center (LICC).
- Right Integrated Control Center (RICC).
- Emergency Integrated Control Center (EICC).
- Auxiliary Integrated Control Center (AICC).
How are the circuit breakers classified
Thermal or electronic
Where are the electronic CBs located
inside the SPDAs, in the electronics bays.
Where are the thermal CBs located
In the cockpit and in the ICCsin the electronics bays
What is the source priority order for powering the airplane
- Respective IDG.
- APU generator.
- GPU (on ground without APU).
- Opposite IDG.
If required the DC GPU can be used for the APU start
What controls load shedding and when does it occur
The SPDAs shed load whenever electrical load increases beyond the system limit
Which items are load shed
Galleys and right windshield heating
What is the chain of electrical power
AC sources (IDGs, APU, external AC) -> electrical busses in the ICCs -> SPDAs -> individual components
Which battery powers the APU starter
Batt 2
What does the static inverter do
Converts 28v DC from the batteries to 115v AC to power the STANDBY AC BUS when an AC power source is not avail.
