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Electricity and Basic Electronics
as a method of generating electricity. Today,
wind turbines are an alternative way of gener-
ating electricity.
A wind turbine, or wind generator,
consists of a tower, spinning blades, and a
generator. The wind turbine in Figure 24-18
is 256′ tall, and the length of each blade is
158′. The total height of the structure is taller
than a thirty-story building. The towers are
tall because as altitude increases, wind speed
increases. Taller towers can capture the higher
wind speeds and generate more electricity.
The blades are connected to the gener-
ator by a gearbox and shaft. The generator is
usually mounted behind the area where the
blades meet, Figure 24-19. Recall that a gener-
ator turns mechanical energy into electrical
energy. The blades of the wind turbine turn
as the wind hits them, spinning the armature
inside the generator. Generators are most effi -
cient when the wind speeds are over 8 miles
per hour (mph).
More windy days and higher wind speeds
mean that more electricity can be generated.
However, at very high wind speeds (over
65 mph), the wind turbine must shut itself
down so it is not destroyed. Wind speed is
measured with an anemometer, which is
typically located above the generator. When
the speed gets too high, the control system
applies the brake. High wind speeds were a
problem with some of the early designs. In fact,
some towers were destroyed when the high
wind caused the blades to defl ect and actually
strike the tower supporting the system.
Wind turbine locations
The amount of wind energy that is avail-
able for a given location changes with the
seasons and weather conditions. However,
there are certain areas in North America where
wind turbines are effectively used because the
average amount of wind is enough to power
them.
Many states now use wind turbines to sup-
ply part of their electricity. States where tur-
bines are found include California, Colorado,
Figure 24-19. The generator sits behind the rotors.
Generator
Figure 24-18. Each blade on the wind turbine is
about the height of a seven-story building.