A simple two-pole DC electric motor has six parts, as shown in the diagram below:

• Armature or rotor

• Commutator

• Brushes

• Axle

• Field magnet

• DC power supply of some sort

•  

• 

An electric motor uses magnets to create motion. Opposites attract and likes repel. So if you have two bar magnets with their ends marked "north" and "south," then the north end of one magnet will attract the south end of the other. On the other hand, the north end of one magnet will repel the north end of the other (and similarly, south will repel south). Inside an electric motor, these attracting and repelling forces create rotational motion.

In the above diagram, you can see two magnets in the motor: The armature (or rotor) is an electromagnet, while the field magnet is a permanent magnet (the field magnet could be an electromagnet as well, but in most small motors it isn't in order to save power).

More Parts
The axle holds the armature and the commutator. The armature is a set of electromagnets, in this case three. The armature in this motor is a set of thin metal plates stacked together, with thin copper wire coiled around each of the three poles of the armature. The two ends of each wire (one wire for each pole) are soldered onto a terminal, and then each of the three terminals is wired to one plate of the commutator. The figures below make it easy to see the armature, terminals and commutator: The final piece of any DC electric motor is the field magnet. The field magnet in this motor is formed by the can itself plus two curved permanent magnets: One end of each magnet rests against a slot cut into the can, and then the retaining clip presses against the other ends of both magnets.

Electromagnets and Motors
To understand how an electric motor works, the key is to understand how the electromagnet works. An electromagnet is the basis of an electric motor. The key to an electric motor is that the field of the electromagnet flips. The flip causes the electromagnet the electric motor to spin freely.

Armature, Commutator and Brushes

The armature is an electromagnet made by coiling thin wire around two or more poles of a metal core. The armature has an axle, and the commutator is attached to the axle. The "flipping the electric field" part of an electric motor is accomplished by two parts: the commutator and the brushes. The diagram at the right shows how the commutator and brushes work together to let current flow to the electromagnet, and also to flip the direction that the electrons are flowing at just the right moment. The contacts of the commutator are attached to the axle of the electromagnet, so they spin with the magnet. The brushes are just two pieces of springy metal or carbon that make contact with the contacts of the commutator.

Putting It All Together
When you put all of these parts together, what you have is a complete electric motor: In this figure, the armature winding has been left out so that it is easier to see the commutator in action. The key thing to notice is that as the armature passes through the horizontal position, the poles of the electromagnet flip. Because of the flip, the north pole of the electromagnet is always above the axle so it can repel the field magnet's north pole and attract the field magnet's south pole.

these parts together, what you have is a complete electric motor:

Motors Everywhere!
Look around your house and you will find that it is filled with electric motors. Here's an interesting experiment for you to try: Walk through your house and count all the motors you find. Starting in the kitchen, there are motors in:

• The fan over the stove and in the microwave oven

• The dispose-all under the sink

• The blender

• The can opener

• The refrigerator - Two or three in fact: one for the compressor, one for the fan inside the refrigerator, as well as one in the icemaker

• The mixer

• The tape player in the answering machine

• Probably even the clock on the oven

In the utility room, there is an electric motor in:

• The washer

• The dryer

• The electric screwdriver

• The vacuum cleaner and the Dustbuster mini-vac

• The electric saw

• The electric drill

• The furnace blower

Even in the bathroom, there's a motor in:

• The fan

• The electric toothbrush

• The hair dryer

• The electric razor

Your car is loaded with electric motors:

• Power windows (a motor in each window)

• Power seats (up to seven motors per seat)

• Fans for the heater and the radiator

• Windshield wipers

• The starter motor

• Electric radio antennas

Plus, there are motors in all sorts of other places:

• Several in the VCR

• Several in a CD player or tape deck

• Many in a computer (each disk drive has two or three, plus there's a fan or two)

• Most toys that move have at least one motor (including Tickle-me-Elmo for its vibrations)

• Electric clocks

• The garage door opener

• Aquarium pumps