An armature is part of an electrical device which includes many current-carrying windings, which rotate within a magnetic field. It is supported in bearings which are set inside end plates. It usually has a ball bearing at the pulley end and a bronze bushing at the other end. If it is turned with a pulley and driven by a V-belt from the crankshaft pulley, it is a generator. If power is fed to the armature it is called a motor.