ELECTRICAL SYSTEM Flashcards
Sources of AC Power
- 2: Engine Generators
- 1: APU Generator
- 1: Ram Air Turbine (RAT)
- External Power
- Static Inverter
Sources of DC Power
- 2 Batteries
- 3: TRU’s (TRU 1/2/ESS)
GCU
- Generator Control Unit
What do the GCU’s do?
- Control output of their respective generator
- Control the frequency and voltage of the GEN output
- Protect the network by controlling the associated (GLC)
The output of an ENG GEN?
115-200V/400Hz/90KVA
3 - Phase
The output of the APU GEN?
115-200V/400Hz/90KVA
3 - Phase
The output of the RAT?
115-200/400Hz/5KVA
3 - Phase
GAPCU
Ground and Auxilliary Power Unit
What does a GAPCU do?
- Regulates, via the APU ECB, frequency and voltage of the APU GEN
- Protects the network by controlling the external power contactor and GLC
Types of CB’s
- Green (Monitored)
- Black (Not-Monitored)
- Red Collared (WTB)
How long until the DC BUS 2 supplies the DC BUS 1 and DC BAT BUS if the AC BUS 1 failed?
- Automatically after 5 seconds
IDG
Integrated Drive Generator
Electrical Priority
- G - Generator (onside)
- E - External Power
- A - APU
- R - RAT
- B - Batteries
BCL
Battery Charging Limiter
Do battery contactors normally stay open or closed?
Open
How do identify battery is on during preflight?
- BAT PB is Recessed
- LDG GEAR Down Lights ON
- Some cockpit lighting
How long does it take for the RAT to power the EMER GEN?
8 seconds
Min Speed for RAT
140 knots
Describe how the EMER GEN obtains its power from the RAT
- RAT is automatically deployed within 8 seconds
- It pressurizes the Blue HYD SYS
- It then powers the hydraulic motor that power the EMER GEN
Which generator normally has more load?
- GEN 1 due to AC BUS 1 powering AC ESS BUS
- Powers the DC BAT BUS through a BTC
