Electric Motors

The average person uses a lot of electricity in the many things they do every day. We are used to being able to turn on a light, watch the television, use our mobile devices, and stream music or videos. Because electricity is so much a part of our lives, we should know something about it.

We have been using fossil fuels to generate electricity and our motors for a very long time. Fossil fuels are not only polluting, but they will eventually run out. The design of an electric motor is a way to alter the generation of electrical energy into mechanical movement.

An electric generator or “dynamo” does the opposite of what we have done in the past and changes mechanical movement into electric energy. Most of the electric motors function using magnetism, but there are also other types of forces as well.

Dissecting an electric motor

A simple electric motor is called a “two-pole DC” type and has six parts:

  • A rotor or armature
  • Commutator
  • Brushes
  • Axle
  • Field magnet
  • DC power supply

The motor makes use of magnets to create the motion required. Since opposite poles of a magnet attract (north and south) and like poles of a magnet repel (north to north or south to south), the electric motor uses two bar magnets with their ends marked north and south to create the magnetic pull.

It also uses the like poles to repel. Inside the motor these magnets are attracting and then repelling on a constant basis to make a rotational motion.

Electric motors are mostly classified in two different types: Direct current (DC) and Alternating current (AC). There are a lot of subtypes in each area and they bring unique qualities that are used for different applications.


One of the fundamental forces of nature that is described in physics is “electromagnetism.” This is the force between electrons and protons, also known as subatomic particles, that helps to hold matter together.

Another description of electromagnetism is how a magnetic field is created by the electric current flow.

The electromagnet

We can create an electromagnet by making an electronic current flow through a wire and generating a magnetic field. This is a major idea in electricity because the power of the magnetic can be increased or decreased by coiling the wire. The wire adjustment allows more or less current to flow through a smaller distance and can adjust the power of the magnetic field.

Figuring out polarity with the right-hand rule

When you wind a wire you have to remember that the magnetic field not only rotates around the wire but the direction of the current is based on the direction of the magnetic field. Scientists have created the “right-hand rule” to figure out the magnetic field.

All you need to do is take your right hand fingers and point your thumb in the direction of the current. Now you wrap your fingers around the wire and they will point in the direction of the magnetic field rotation.

Importance of electric motors

 Electromagnetism is the basis for electric motors and the electric motor converts electrical energy into motion or movement. The magnetic field creates a force that causes a spinning or motion that runs the motor.

Cutaway view through stator of induction motor.

Beyond the initial idea of automobiles, the applications for electric motors have expanded into everything from a fan to operating a hard drive and the open/shut mechanics of that CDROM drive.

Electromagnetic Induction

One of the other critical things to know about electromagnetism is “induction.”  We are used to hearing about electricity being used to create movement, but induction is the opposite: when movement is used to create electricity.

Electric generators

Electric generators are becoming more and more important around the world. These devices use induction to convert mechanical energy into electrical energy.

The explanation for this is to know that when a coil of wire is spun between two opposite magnet poles, it creates an electric current that can then be used to power electronic devices. Generators can get power from renewable and sustainable sources such as wind, solar, and hydropower.

Fun Facts about Electric Motors

  • Some of the first electric generators were driven by the power of humans with hand cranks and even bicycles for electricity generation.
  • Electromagnets are used in loudspeakers to vibrate the cone and then produce sound.
  • Electromagnetism makes use of magnets that can be very powerful and be turned on and off using electricity.


What electric motor design is opposite of the fossil fuel motors?
a way to alter the generation of electrical energy into mechanical movement

What are the 6 parts of a simple two-pole DC electric motor?
A rotor or armature, Commutator, Brushes, Axle, Field magnet and DC power supply

How can electric motors benefit the planet?
they can use renewable and sustainable energy that doesn’t pollute

What is “induction?”
when movement is used to create electricity

What is electromagnetism?
a magnetic field that is created by the electric current flow