Small and large appliances have a motor , a heating element , or both. Motors are important components to hundreds of devices we use in daily life. This guide will show you how motors work and how to fix them when they don't.

How Does It Work?

A motor turns electrical energy into motion. Actually, it uses electricity's magnetism to attract, then repel components to rotate a shaft. You can attach fan blades, knife blades, wheels, or a dozen other components to the shaft to make useful devices. To name a few: blender, cassette deck, CD player, coffee grinder, computer fan, computer printer head, DVD player, electric can opener. . .you get the idea. These and hundreds of other functional gadgets rely on electric motors to give them motion.

Smaller appliances typically use what's called a universal motor. It's simple, efficient, and relatively inexpensive. It's called "universal" because it can run on either alternating current (AC) or direct current (DC) power. The part that stands still is called the stator and the rotating part is the rotor. It's as simple as that.

Some small appliances use a variation called the shaded-pole motor. It works about the same as the universal motor, but is less expensive to manufacture so it typically goes into lower-cost, low-load, small appliances.

Larger appliances, as you can imagine, require more power. Many use a split-phase induction motor to develop more rotating power, called torque, than smaller motors can muster. Split-phase induction motors, too, have stators and rotors.

Smaller things, such as battery-operated appliances and tools, get their power from DC batteries so they are made to run on direct current. They don't have much motion or torque, but they get the job done in a small space.

You can see the commutator and the rotor inside this motor from a variable-speed food mixer.

What's the difference? Usually it's cost. Most manufacturers use the least expensive motor that does the job. Fortunately, checking whether a motor runs or doesn't is about the same for any type of motor. Unless you're adventuresome, you probably won't dismantle a motor and replace components. If it works, you'll use it; if not, you'll recycle it.

Many motors include a drive mechanism of some type that transfers the shaft rotation to some other component. You can fix or replace drive mechanisms as well (see below).

What Can Go Wrong?

Turning on and off the motor's brushes (left, top, and bottom) creates a magnetic field that makes the motor shaft rotate.

Though efficient, motors can work against themselves. A small problem can become a big one quickly and, soon, the motor is damaged beyond repair. Fortunately, most motors will tell you--sometimes subtly, sometimes not--that they are having problems. Motors burn out and freeze up; they get noisy, overheat, and wobble.

Fix-It Tip

Hearing noises that may be a motor going out? Turn off the appliance immediately. It may be something rubbing against the moving parts or it may be a problem in the motor itself. In either case, the faster you catch it the easier it will be to troubleshoot and fix it.