How many TR's are installed in the electrical system?

How many TR's are installed in the electrical system?

• A. Two
• B. Three
• C. Four
• D. Six

Answer: (B)

This question tests how many Transformer Rectifier units (TRUs) the A320 uses and why that number is chosen. TRUs convert 115 VAC from the aircraft’s generators (and the APU when available) into 28 V DC to feed the DC distribution system. The A320 employs three TRUs to provide redundancy and maintain DC power to the buses even if one TRU is unavailable. With three units, if one fails or is taken offline, the remaining two can still supply the essential DC power without compromising systems. Having only two TRUs would risk losing DC power during a fault, while more than three would add weight and complexity without added benefit. So three is the standard installation.

This question tests how many Transformer Rectifier units (TRUs) the A320 uses and why that number is chosen. TRUs convert 115 VAC from the aircraft’s generators (and the APU when available) into 28 V DC to feed the DC distribution system. The A320 employs three TRUs to provide redundancy and maintain DC power to the buses even if one TRU is unavailable. With three units, if one fails or is taken offline, the remaining two can still supply the essential DC power without compromising systems. Having only two TRUs would risk losing DC power during a fault, while more than three would add weight and complexity without added benefit. So three is the standard installation.