A brushless alternator consists of two alternators constructed from end to end on an axis. Smaller brushless alternators may look like a unit, but the two parts are easily identifiable in large versions. The larger of the two sections is the main alternator and the smaller is the exciter. The exciter has stationary field coils and a rotating armature (power coils). The main alternator uses the opposite configuration with a rotating field and a stationary armature.