How a simple motor works (Structure of dc motor)

The most commonly used simple electric motor is a DC motor. This type of motor has a rotational speed that depends on the DC voltage applied to it. Although they are easy to manufacture, they do not meet the requirements for capacity and reliability. Today’s article will show how a simple motor works.

Electromagnet

Electromagnets have a north pole and a south pole. The magnet will attract metal objects toward it. If we have two magnets placed close to each other: the same pole repels, and the opposite pole attracts. The figure below shows how permanent magnets work.

How permanent magnets work

Now we’re going to make a simple electromagnet with a bolt wrapped around a lot of wire. When we apply a voltage to the coil, the current flowing through the wire will create a magnetic field around it. It can do the same things that a permanent magnet can. It can pick up pieces of metal, and it has a north and a south pole.

Now, if we change the direction of the voltage by rotating the battery, this will cause the poles on our magnet to switch places. North will become south, and south will become north.

Electromagnet (Source: hvrmagnet)

A simple electric motor works on the force of interaction between an electromagnet and a permanent magnet.

Structure of DC Motor

The commutator is to keep the direction of the current in the armature winding constant. DC voltage is supplied to the armature winding through the brush in contact with the commutator.

Structure of a simple motor (Source: xenangthienson)

How a simple motor work

When we apply DC voltage to the two brushes, a current will appear in the rotor winding. The rods ab and cd will carry current placed in the magnetic field, so the rods will experience a force F that rotates the rotor. The direction of force F is determined by the left-hand rule.

When the rotor rotates half a turn, the positions of the rods ab and cd will change places. Due to the commutator that helps to change the direction of the current, the direction of the rotational force F remains constant. Make sure the motor only rotates in one direction.