Motor assembly

Electrically, a motor consists of two components which move relative to each other and which together form a magnetic circuit:

Field magnets - This part creates a magnetic field which passes through the armature. It is usually a set of electromagnets surrounding the rotor, consisting of wire windings on a ferromagnetic iron core which guides the magnetic field. Alternatively it can be one or more permanent magnets.

Armature - This is the part through which the electric current flows which develops the force. Like field coils, it consists of wire windings on a ferromagnetic core. When electric current passes through the wire the magnetic field from the field magnet exerts a force on it, called the Lorentz force, turning the rotor.

One of these components is mounted on the stator, the stationary part of the motor attached to the frame, the other is on the rotor, the part that turns. The field magnet is usually on the stator and the armature on the rotor, but in some types of motor these are reversed.

Mechanically, a motor consists of these parts