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electrical system for a twin-engine commercial aircraft - Coggle Diagram
electrical system for a twin-engine commercial aircraft
SYSTEM
AC DC buses
batteries
Inverters
Monitoring and control systems
two generators
power generation
Generator rating sized for steady-state and peak load with margin (~15–20 kW per generator)
Emergency/standby generator (APU or RAT) for backup power
Voltage level: typically 115 VAC, 400 Hz (primary AC supply)
Aircraft batteries for DC emergency power
Engine-driven generators on each engine
Power distribution
AC buses supply main loads (lighting, galley, air conditioning, avionics
DC buses supply flight controls, navigation, communications
Separate essential and non-essential buses
Bus tie and isolating devices to manage normal, abnormal, and emergency power flows
load types and priorities
Non-Essential Loads: cabin lighting, passenger outlets, galley, entertainment systems
Load shedding schemes for abnormal/emergency situations to preserve essential power
Essential Loads: flight controls, navigation, communication, engine control, instrument displays
Power Conversion and Regulation
Static inverters to convert DC back to AC for specific systems if needed
Transformer Rectifier Units (TRUs) to convert AC to DC for avionics and controls
Voltage regulation and protection devices
Emergency and Backup Systems
Emergency power sources: Auxiliary Power Unit (APU) or Ram Air Turbine (RAT) generators
Automatic switching to emergency power during main generator failure
Batteries sized to power essential DC loads for a minimum safe duration (e.g., 30 min)