Speedy DC Motor: How it works

In order to create an efficient DC motor one must first understand how it works. Below is an image of said motor, and though the design is not entirely the same as the one I built, it works in the same fashion.

DC Motor

This motor runs by using two electromagnets (In the diagram above there is only one, as the second magnet is a permanent one). An electromagnet is a metal object that becomes a magnet when a current is sent through a wire wrapped around it. As soon as the current is removed, the metal object returns to being nonmagnetic. Why does this happen? 

Before a current is run through it, the metal object's domains are randomly aligned. Each electron that runs through the wire has its own small magnetic field which is increased each time the coil is wrapped around the rod. This magnetic force straightens out the mismatched domains of the metal object, and gives it a north and south pole.

Electromagnet Diagram

The motor spins as the similar poles of the two magnets repel. The commutator holds two copper pieces that aren't touching, and that is what allows the motor to keep spinning. The brushes temporarily lose contact with the copper, breaking the circuit. When the they touch the copper pieces again, the poles of the electromagnet are reversed. Thus, as the magnet turns, the like poles repel, and the cycle continues.

Design of my DC motor

http://www.evilmadscientist.com/2006/building-an-electric-motor/

http://science.howstuffworks.com/electromagnet2.htm