Definition
The rotating component of an electric motor or generator, typically consisting of a shaft-mounted core wound with insulated wire coils, in which voltage is induced or through which current flows to produce torque. In a magneto, the armature is the rotating assembly that turns within a magnetic field to generate the high-voltage spark used to fire the engine's ignition.
Plain English
The spinning part inside a motor, generator, or magneto where electricity is produced or used to make the shaft turn.
Context Anchor
Seen in aircraft electrical system maintenance, especially when inspecting or troubleshooting starters, motors, and generators.
Derivation
From the Latin armatura, meaning 'armor' or 'equipment.' Early electrical engineers used it to describe the iron piece 'fitted' across the poles of a magnet. The sense of a fitted, working part carried over into modern motors and generators.
Why Pilots Care
The armature is the component that actually generates or converts electrical power in engine-driven units; damage here stops charging or starting.
Intuition Check
Do not read “armature” as a structural arm or support. In this maintenance context, it means the working electrical core of a motor or generator.
Example Sentence 1
The mechanic replaced the starter after finding the armature windings burned through.
Example Sentence 2
Current flowing through the starter motor armature produces the torque needed to turn the engine.