Electric Motors

Electric Circuits

An electric circuit is an electrical path that begins at a power source and ends up back at the power source.

The component that is being powered by the source is called the load.

If the circuit isn’t complete, electrons will stop flowing, which will turn off the electricity.

Direct Current (DC)

In a DC circuit, electrons flow in one direction from the negative terminal to the positive terminal.

Alternating Current (AC)

The electrons that flow in an AC circuit alternate.

(In other words they go back and forth)

Conductors & Insulators

Conductor - A material whose atoms easily give up their outer electrons, letting an electrical current flow easily through the material

Insulator - A material whose atoms hold their outer electrons tightly, resisting the flow of electrical current through the material

Electricity and Magnetism

Electricity flowing through a wire creates a magnetic field around the wire.

Electricity and Magnetism

A coil of wire that has an electric current passed through it becomes an electromagnet.

By having more coils (wraps) you increasethe magnetic field.

What do we know about magnets?

Opposite poles attract and like poles repel.

Inside an electric motor these attracting and repelling forces create rotary motion.

Motors in your kitchen…

The fan over the stove and in the microwave oven

The disposal 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

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Motors in your basement or garage …

The washerThe dryer The electric screwdriver The vacuum cleaner (Dustbuster or Shop

Vac)The electric saw The electric drill The furnace blower

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Motors in your bathroom…

The fan The electric toothbrush The hair dryer The electric razor

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Motors in your car….

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

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Other places too!

Several in the VCR and DVD playerSeveral 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

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HOMEWORK

Armed with your new knowledge of electrical motors and the experience of building one, you are going to use your motor to teach someone else how it works. Your lesson can be given to any adult and must be completed _________ ___________. Your “student” needs to fill out the brief description of your lesson on the sheet provided.