E175 Electrical Flashcards
(38 cards)
How many networks make up the electrical system on the airplane? Why?
- 2 independent networks
- Redundancy and fault isolation
What happens if a power generating source fails?
Bus ties automatically connect to provide no system degradation
What components power the AC system?
- 2 Integrated Drive Generators (IDG)
- Auxiliary Power Unit (APU)
- Inverter
- Ram Air Turbine (RAT)
- AC GPU receptacle
What components power the DC system?
- 2 NiCad batteries
- 3 Transformer Rectifier Units (TRU)
- DC GPU receptacle
How do IDG maintain a stable power output?
A Constant Speed Drive (CSD) attaches the IDG to the Accessory Gear Box (AGB)
What monitors and controls the IDG?
Each has a Generator Control Unit (GCU)
Can one IDG supply the entire electrical system?
Yes
What will cause the amber IDG light on overhead panel to illuminate?
- high oil temp
- low oil pressure
If an IDG is manually disconnected can it be reconnected by flight crew?
No. This is a maintenance function
What is the primary purpose of AC generators?
- to power the AC BUSSES and AC ESS BUS which…
- power the 3 TRU (1,2 & ESS)
What is the purpose of the TRUs?
To convert 115 VAC to 28 VDC
Can the APU replace a failed IDG?
Yes
What is the AC electrical systems priority?
- (onside) IDG
- (inside) APU
- (outside) GPU
- (cross-side) other IDG
How is it known that an AC GPU is hooked up to the airplane and ready to provide electricity?
- GPU button displays AVAILand the GPU icon is presented on the electrical synoptic page
- Once the GPU button is pushed in, the button will display IN USEprovided another AC power source is notavailable.
What does it mean if the AC GPU is plugged in and the outside GPU panel button displays IN USE?
- Ground service bus is in use
- Cockpit GPU button will display AVAILeven though the ground service bus is in use
If the airplane is using the AC GPU and the APUis 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 aircraft’s batteries last with no recharging?
10 minutes
What is the purpose of the DC GPU receptacle?
- For APU start when batteries < 22.5 VDC, or
- If battery temp is < -20°C
What is the minimum battery temp for APU start?
-20°C
What is the minimum battery voltage to close the battery bus-ties?
18 volts
What battery is used for the APU start?
- BATT 2 powers the APU Start Bus
- BATT 1 powers the FADEC & EICAS for monitoring
What is the purpose of the Inverter?
Converts 28 VDC from the batteries to 115 VAC to power the AC STANDBY BUS when an AC source is notavailable
What is on theAC STANDBY BUS?
Engine exciters 1A and 2A
