, “. ~ .- ,_ . * -I ' REFERENCE- .? -BBRARY p ;A ~~~ect;~~~vol ...

Wind Power”Systems .
system becomes one of the many intercon-
netted generators the grid uses for its power
supply. At a certain windspeed, when more
shaft pow& than the pump needs is avail-
able from the Darrieus rotor, the rotor over-
powers the electric motor, trying to turn it.
fastefi-than it was designed’ to turn. The
motor then becomes an AC generator syn-
chronjzed with the grid power. Should the
electric pdwer available actually exceed the
demands at the site, the excesar
energy is fed back into the grid, effectively
“running the meter backwards.“Thtis, energy
storage for this system is provided mostly
i
,a by pumped water in a pond or a tank and
4occasionally by ithe grid power lines that ,_
“store” electricity sent bakkwarc@ thrpugh
----d&emoter.
The unique advantage of the Bushland
i’nstallation is that the electric motor actually
serves three purposes-almost at once. First,
~ the m&or is the prime mover driving the-well
pump. S_econd, the motor is the governor for
the wind‘rotor; it wants to turn only at an rpm
determined by the AC frequency fed to it
from the grid. By baleful design, th;! rotor
will never overpower the motor 0; cause it to
overspeed by more than a few rpm. Finally,
* the motor is an electric generator whenever
extra wind power is availabl’e.
Once.pehected, this abproach ‘ian be
readily adapted to thousandsof well pumps
already in existence in the windiest parts of
the United State$.and similar locales through-
out the world: t&nor modifications to these
pumps will permit the addition of wind po.$pr,
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IRRIGATION DITCH
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DARRIEUS “ECG&ITER
ROTbR
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‘\ ’ \
‘. MOTOR @
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POWER SHAFT
In the novel approach being tested $t Bushland by the USDA, both wind power
and an electric motor are used simultaneously to power the well pump. If excess
wind power IS avallable. the system delrvers It io the utility lines.
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