Which device converts external AC power to DC power for the aircraft's DC buses and battery charging?

Which device converts external AC power to DC power for the aircraft's DC buses and battery charging?

• A. Transformer Rectifier Units
• B. Inverters
• C. Generators
• D. External power receptacle

Answer: (A)

Transformer rectifier units convert AC power into the DC power used by the aircraft’s DC buses and to charge the battery. They take the AC input (such as from an external power source on the ground or from the aircraft’s AC generators) and rectify it to a stable DC voltage (commonly 28 V DC). The external power receptacle is just the source of AC; it doesn’t do the conversion. Inverters would do the opposite (DC to AC), and generators produce AC power, which TRUs then rectify to DC. So the device that supplies DC power for the DC buses and battery charging is the transformer rectifier unit.

Transformer rectifier units convert AC power into the DC power used by the aircraft’s DC buses and to charge the battery. They take the AC input (such as from an external power source on the ground or from the aircraft’s AC generators) and rectify it to a stable DC voltage (commonly 28 V DC). The external power receptacle is just the source of AC; it doesn’t do the conversion. Inverters would do the opposite (DC to AC), and generators produce AC power, which TRUs then rectify to DC. So the device that supplies DC power for the DC buses and battery charging is the transformer rectifier unit.