Chapter 8 Electrical Engineering 139
See Figure 8-6. In coal, nuclear, and natural gas
power plants, tremendous amounts of steam are
generated. This steam is used to turn massive
turbines, creating rotary motion that spins a
generator. In hydroelectric dams, falling water is
used to turn turbines. These turbines then turn
generators. In wind farms, turbine blades are
turned by the wind to create rotary motion for
the generator.
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Figure 8-5.
When a ball is pushed into one end, a ball comes out the other end immediately. Each ball in the tube moved a short
distance, but the effect was that one ball moved very quickly.
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Magnetism
Magnets are important in the area of electri-
cal engineering because they are used to generate
electricity. A magnet is usually made of iron, steel,
or a mixture of metals. A magnet contains polari-
ties. Polarity describes the direction of a magnetic
field. The magnetic field is strongest at a magnet’s
poles, each in the direction opposite of the other. A
magnet has two poles. The Earth is considered a
magnet with two poles: north and south.
Every magnet has two poles. If you cut a magnet
in half, each piece would then have two poles. Like
poles repel each other, while opposite poles attract.
For example, the north pole of one magnet will attract
the south pole of another magnet. However, the north
poles of two magnets will push away from each other.
Every magnet has a magnetic field created by
its poles. A stronger magnetic field is created between
two magnets with opposite poles. The field surrounds
the magnets and pulls them closer together. The
magnetic fields of two magnets with similar poles are
different. Because the magnets repel each other, their
magnetic fields stay as they are.
Science
Armature
Magnets
This simple generator produces electricity by changing
mechanical engery to electrical energy.
Figure 8-6.
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