How A Motor Works

How a Motor Works

Parts of a Motor

Building a simple motor, while seemingly daunting, is actually a simple task to do. A simple motor requires five main components: 

• Field Magnet
• Armature
• Commutator/Brushes
• Shaft (or Axle)
• A DC Battery

With all of these pieces working together, the field magnet will make the armature spin, allowing for motion and uses such as pulling a toy car on a loom. Here, I will explain a bit about magnets and how each piece works and connects so that the motor can work.

Magnets/Field Magnet

A motor uses magnetism to create motion. A magnet has two poles, a northern one and a southern one. If you have ever played with simple magnets, you know that like poles repel and unlike poles attract. This is the basis for the electric motor. Furthermore, an electric motor uses something called an electromagnet to create motion. An electromagnet is a device that creates a magnetic field through electricity. It simply requires some single strand copper wire and a piece of metal. By wrapping the wire around the metal, and attatching each end to a battery, the current flows through the wire and creates a magnetic field around the electromagnet. This is the basis of building a simple motor. The field magnet is an electromagnet that has a strong magnetic field so that the armature can spin rapidly. More on how the armature reacts with the magnetic poles in the next section. 

                         An Electromagnet                                                                         Field Magnet Diagram

Armature

The armature is made up of two pieces of metal with lower gauge magnet wire wrapped around them. They go through the shaft, or an axle, which is basically a metal rod in which the armature and commutator goes through. The armature is what causes motion when it reacts to the magnetic field caused by the electromagnet. When the wire is wrapped around the two pieces of metal, it basically becomes a magnet as well, with two poles at the north and south ends. When the electromagnet is activated, it has two poles as well. Naturally, the two like poles are repelled from one another, so the armature spins so that the unlike poles are near one another. This motion is what makes the motor spin.

Commutator/Brushes

The "flipping of the magnetic field is accomplished by the brushes and the commutator. The brushes are what send the electricity into the commutator. It allows the electricity to flow into the armature and is what flips the direction of the poles. By reversing the current each half turn, it keeps the armature spinning in the same direction. The brushes are made wider than the insulated gap, to make sure that the brushes are always touching a bit of copper. It is connected to the armature from the magnetic wire wrapped around the armature.

  Shaft/Axle

The shaft is a metal rod that contains the commutator and armature. 

DC Battery 

A DC Battery is necessary to provide electricity and complete the circuit. 

Connections

With all of these pieces connected, electricity can flow through a complete circuit and the armature spins rapidly over the electromagnet. Then it can pull a toy car (hopefully!). A gif of how the motor is supposed to work.

Sources for this post:

http://electronics.howstuffworks.com/motor6.htm

http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/motdc.html#c2