As mentioned before, electric motors are either alternative current (AC) or direct current (DC). Electric motors are simple, scalable machines. Some main categories are DC motors, universal motors, step motors and AC motors.

In this post, we are going to talk about DC motors. DC motors are easier to control than AC motors. But AC motors have a simpler design and easier to maintain. Here is how a DC motor works:

The main principle of any electric motor is based on magnetic field. DC current flows through wire goes through pieces of graphite calls brush which transmits current through commutator (two or more semi-circle split rings). The commutator is connected to a large coil of wire called the armature and to the output shaft.

Current flows the commutator through the armature then back to the commutator. Current then flows through another brush to one or more electromagnets each made up of a wire coil wrapped around a piece of iron. This flow of current produces a field of magnetism and attraction and repulsion of these two magnetic fields made the commutator and the rotor to rotate in one direction. The direction of the motion depends upon the directions of the field and the current.

Stator is the stationary part of the motor. Current flowing through the stator coil, a magnetic field in a specific direction is produced. On the other hand, rotor which is the rotating part of the motor, produces a magnetic field in a direction compared to stator. According to Lorentz law, when a conductive material is embedded in a magnetic field, a force in induced to it. This force makes the rotor to rotate. As DC field is constant, the direction of this rotation is also constant.

DC motors has three sub-categories: brushed motors, brushless motors and servo motors. We will discuss these later.