Credit Points 5
WHAT MAKES MOTORS RUN
What makes an electric motor run? Can you make an electric motor that will run? Certainly you can, and by doing so you'll learn why it runs. It won't be mysterious any more and you'll be ahead of all the millions of people who use motors every day and never know why or how the motor converts electrical energy into useful power.
Motors Are Magnets
You know how one end of a compass needle always points to North. No matter how you turn the compass, the same end of the needle always swings to the North. The earth itself and that small compass are both magnets (Figure 1). Each has a North pole and a South pole. Around the poles of each there are magnetic fields, invisible lines of force that attract and repel.
Figure 1. The same end of the compass needle always points to the earth's magnetic North Pole.
The N poles repel each other and so do the S poles. The N and S poles attract each other. In other words, opposite poles attract; poles that are alike repel each other.
Lay 2 bar magnets on a table side-by-side. If both N poles are at one end, they'll repel each other and almost flip around until there's a N pole lying next to a S pole (Figure 2).