Definition
An electrical component that first transforms alternating current (AC) to a different voltage, then rectifies it into direct current (DC). On aircraft with AC electrical systems, TR units supply the DC needed by batteries, avionics, and DC-powered equipment.
Plain English
A device that takes AC power, steps it down to a useful voltage, and then converts it into DC power so the aircraft's DC systems can use it.
Context Anchor
Seen in aircraft electrical system descriptions, maintenance troubleshooting, and cockpit alerts related to electrical power.
Derivation
Transformer changes voltage levels in an AC circuit; rectifier changes AC into DC. A TR unit does both jobs in one box, hence transformer-rectifier.
Why Pilots Care
Reduces landing roll distance and brake wear, improving safety on shorter or contaminated runways.
Intuition Check
TR does not mean a radio transmit/receive control here. In this maintenance context, it means transformer-rectifier: a unit that converts aircraft electrical power.
Example Sentence 1
The aircraft has two TR units, each capable of supplying the entire DC bus if the other fails.
Example Sentence 2
Maintenance checked the TR unit actuators during the post-flight inspection.