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Twin-Engine Commercial Aircraft Electrical System - Coggle Diagram
Twin-Engine Commercial Aircraft Electrical System
Power Generator
Primary: 2 × IDGs (115/200V AC, 400 Hz, 30 kVA)
Backup: APU Generator (30 kVA)
Emergency: RAT (5–10 kW) + Battery (28V, 40 Ah)
Power Distribution
AC Buses
Main (115/200V for non-essential loads)
Essential (backed by battery/RAT)
DC Buses
Main (28V via TRUs)
Battery (direct to critical loads)
Control
Bus Tie Breakers (BTBs) for fault isolation
Load Shedding: Non-essential loads disconnected during failures
Power Conversion
TRUs: 115/200V AC → 28V DC (e.g., 100A/2.8 kW)
Static Inverters: 28V DC → 115V AC (e.g., 3 kVA)
ATRUs: 200V AC → 270V DC for high-power loads
Control & Protection
GCUs: Voltage/frequency regulation for IDGs
BPCUs: Bus power management & fault response
Circuit Protection
Thermal/Magnetic Breakers
Fuses for high-current paths
Redundancy
N+1 Architecture: Critical loads powered if 1 generator fails
Cross-Bus Feeding (via BTBs)
Independent Channels per engine
Safety Systems
Static Dischargers: Prevent avionic interference
Grounding Points
NLG/MLG for refueling safety
Engine inlets/wings
Bonding Cables: Aircraft-refueler continuity
Key Requirements
DO-160G Compliance
80% Load Margin
30-min Battery