In a relay, regulator, horn, etc., it is the movable part of the unit. In a starter or generator, it is the portion that revolves between the pole shoes, made up of wire windings of copper on an iron core or axle. When it revolves, an electric current is induced.
ARMATURE
Meaning of ARMATURE in English
English dictionary of automotive terms. Английский словарь автомобильных терминов. 2012