Electrical Flashcards
APU Model
Sunstrand APS 2300
Which battery is used for APU start?
- Which battery is used for APU start? Batt 2 powers the starter
- Batt 1 powers FADEC and EICAS
What fuel pump is used for APU start?
Batteries on - DC pump in right tank
AC power - ACMP 2
Right engine running - ejector fuel pump
Will APU shut down automatically during hung start?
Yes
What does moving APU switch to off do?
What does moving APU switch to off do? Initiates shutdown 1-minute cool down No pneumatics (1 min of electric)
What happens if a power generating source fails?
Bus ties automatically connect to provide no system degredation
What components power the AC system?
- 2 IDGs
- APU
- Inverter
- Ram Air Turbine
- AC GPU Receptacle
What components power the DC system?
- 2 NiCad batteries
- 3 TRUs
- DC GPU receptacle
How does the IDG maintain a stable power output?
A CSD attaches the IDG to the AGB
What monitors and controls the IDGs?
GCU
What will cause the amber IDG light on the overhead panel to illuminate?
High oil temperature
Low oil pressure
If an IDG is manually disconnected, can it be reconnected by the flight crew?
No. Mx only
What is the primary purpose of the AC generators?
To power the AC busses and AC ESS bus, which power the 3 TRUs
What is the purpose of the TRUs?
Convert 115 VAC to 28 VDC
Can the APU replace a failed IDG?
Yes
What is the AC electrical systems priority?
Onside, inside, outside, crossside
* Uses onboard AC power before external
How is it known that an AC GPU is hooked up and ready to use?
GPU icon will show on electrical synoptic page
Avail light will illuminate
If the airplane is using the AC GPU and the APU is started , what should the pilot be sure to do?
Deselect the GPU button before the next GPU connection
What will charge the batteries?
Any AC power source
How long will the aircrafts batteries last with no recharging?
10 minutes
What is the purpose of the DC GPU receptacle?
For APU start with voltage
What is the minimum battery temp for APU start?
-20 C
What is the minimum battery voltage to close the bus ties?
18 volts
What battery is used for the APU start?
Batt 2 powers the start bus
Batt 1 powers the FADEC and EICAS for monitoring
What is the purpose of the inverter?
Converts 28VDC to 115VAC from batteries to power AC STANDBY BUS when AC source isn’t available
What is on the AC STANDBY BUS?
Engine 1A and 2A exciters
What powers the RAT?
Airflow turns the RAT propeller which spins the turbine inside
When will the RAT deploy?
Automatically deploys if AC BUSes are not powered or manually
How long after deployment before the RAT will supply power?
8 seconds
Is there a total loss of power during the 8 second RAT deployment?
No. Batteries supply power to the DC ESS BUSes and AC STANDBY BUS
What does the RAT power?
ESS BUSSES
What is the minimum airspeed for the rat?
Load shedding begins at 130 KIAS
When is the RAT icon displayed on the electrical synoptic page?
When the RAT is deployed
What manages the electrical system?
4 ICCs and 2 SPDAs
What is an ICC?
An electrical control device that provides power distribution and protection for electrical loads
What is an SPDA?
An electrical load management unit that distributes electrical loads to the aircraft systems according to system logic
Can the flight
ICC CBs can only be reset by mx
SPDA CBs can be reset via the MCDU
