A dc motor is used to convert electrical energy in to mechanical energy, and is designed to run on direct currents. Its most important parts are the rotor: the stator and the brush gear.

The rotor is the moving part. It contains an armature which are a set of wire loops wound on a steel core. When a current is fed to the armature, these windings produce a magnetic field. The armature and the core are mounted on a shaft which runs on bearings. It provides a mean of transmitting power from the motor.

the rotor contains a commutator. this consists of a number of copper segments insulated from one another. The armature windings are connected to these segments. Carbon brushes are held in contact with the commutator by spring. These brushes allow current to pass to armature windings. As the rotor turns, the commutator acts as a swich making the current in the armature alternate.

The stator does not move. It consists of magnetic and electrical conductors. The magnetic circuit is made up of the frame and tho poles. Wound round the poles are the field coils. These from the stator's electrical circuit. When a current is fed to them, a magnetic field is set up in the stator.

The motor operates on the principle that when a current-carrying conductor is placed in a magnetic field, a force is produced on the conductor. The interaction of the forces produced by the magnetic field of the rotor and the stator makes the rotor spin.