Editing Electromagnetic coil (section)

===Electric machines===
[[Electric machine]]s such as [[electric motor|motors]] and [[electric generator|generators]] have one or more windings which interact with moving magnetic fields to convert electrical energy to mechanical energy.  Often a machine will have one winding through which passes most of the power of the machine (the [[Armature (electrical engineering)|"armature"]]), and a second winding which provides the magnetic field of the rotating element ( the "field winding") which may be connected by brushes or slip rings to an external source of electric current. In an [[induction motor]], the "field" winding of the rotor is energized by the slow relative motion between the rotating winding and the rotating magnetic field produced by the stator winding, which induces the necessary exciting current in the rotor.