thumb|[[Rotor (electric)|Rotor (lower left) and stator (upper right) of an electric motor]]
thumb|Stator of a 3-phase AC-motor
thumb|Stator of a brushless DC motor from computer cooler fan
Electric machines function through the interaction between a rotating component, the rotor, and a non-rotating component, the stator. In an electric motor, the stator provides a magnetic field that drives the rotating armature; in a generator, the stator converts the rotating magnetic field to electric current.
Design
Motor stators are made either from iron/steel or from a printed circuit board (PCB). Originally applied to low-power applications, PCB stators can be lighter, smaller, and less noisy.
One design embeds thin copper traces in the PCB stator that serve as the windings. The traces are interleaved with epoxy-glass laminates, that insulate each coil from its neighbors. An air core replaces the traditional iron core, saving space and weight, and allowing a smaller air gap.