How does a motor work?

We’re going to explain how a motor is able to rotate, which is why cars or other devices with motors are able to work the way they do.

external image motor-labels.gif

Outline of a motor, with current and magnets


Most motors have 6 parts. These parts are all labeled in the diagram above, and all have specific roles.

- Armature or rotor – electromagnet, part of circuit

- Commutator - a rotary electrical switch in certain types of electric motors or electrical generators that periodically reverses the current direction between the rotor and the external circuit

- Brushes - serve as part of circuit to help get current through

- Axle - a central shaft for a rotating wheel or gear.

- Field magnet – to create magnetic field which makes rotation

- DC power supply of some sort – to provide charge for the current

How does it work?

As you can see in the picture above, a motor works based on magnets. Magnets have two poles, south and north. Opposites attract, and similar poles repel each other. In motors, there are two bar magnets across from each other, one south and one north. They attract so this creates a rotational motion which is what makes the motor run. The armature is an electromagnet, which is a magnet whose magnetic field is produced by the flow of electric current. The field magnets are permanent magnets.

The motor has a circuit which includes the axle, commutator, brushes, and armature. The axle is the central shaft attached to the commutator. The commutator is is a rotary electrical switch that periodically reverses the current direction between the armature and the external circuit. The brushes work with the circuit to let current flow to the electromagnet. The armature is part of the circuit, the wires that are connected to the batteries.

While the circuit works with a current, the north and south field magnets attract to each other creating a magnetic field. This magnetic field reacts with the current to create a rotational motion which powers the motor.

– Video on how magnets affect motors. It shows the motor using magnets to create motion. One magnet is coiled up by the wires, and due to the fact that the magnet has a north and south end, the north end of the another magnet will attract the south end of the magnet that is coiled up and repel the north end of the magnet that is coiled up, and the south end will do that same except the opposite. The constant repelling and attracting force creates a rotaional motion. The inside magnet being charged by the battery is charged and reacts to the outer magnets.