What is the function of the DC-AC conversion system (TRUs) in normal operation?

What is the function of the DC-AC conversion system (TRUs) in normal operation?

• A. They convert AC power to DC power for the DC buses.
• B. They convert DC power to AC power for the AC buses.
• C. They regulate cabin lighting.
• D. They manage hydraulic pumps.

Answer: (A)

TRUs are the devices that provide DC power by rectifying the AC power from the generators or APU. In normal operation, AC power is fed into the TRU, where a transformer adjusts the voltage and rectifier circuitry converts it into DC. This DC power, typically around 28 volts, is then distributed to the DC buses to run avionics, instruments, lighting, and other DC-powered systems, and it also charges the aircraft battery. This role is distinct from an inverter, which would convert DC back to AC if needed. So the function is to supply stable DC power to the DC distribution system from the AC sources.

TRUs are the devices that provide DC power by rectifying the AC power from the generators or APU. In normal operation, AC power is fed into the TRU, where a transformer adjusts the voltage and rectifier circuitry converts it into DC. This DC power, typically around 28 volts, is then distributed to the DC buses to run avionics, instruments, lighting, and other DC-powered systems, and it also charges the aircraft battery. This role is distinct from an inverter, which would convert DC back to AC if needed. So the function is to supply stable DC power to the DC distribution system from the AC sources.