Terrestrial Mounting; Guyed Towers - ECLECTIC ENERGY D400 User Manual

Terrestrial Mounting

The performance of your D400 will be influenced by the topography of your proposed
mounting site. The golden rule with wind turbines is to mount them as high as is practically
possible. The higher the turbine is mounted, the more productive it will be. This is because
Wind speeds reduce steadily as they approach the ground due to the effect of friction
between the airstream and the earth's surface. This 'wind shear' effect is less marked over
smooth surfaces such as the sea, and more marked over 'rough' surfaces such as woods or
urban areas. Obstructions such as trees and buildings also introduce turbulence into the
airflow, and no wind turbine works at its best in turbulent air. Given that low wind speeds and
turbulent airflow will greatly reduce the efficiency of any wind turbine, it is important to locate
the D400 in the clearest, fastest airflow possible.
Aim to mount your D400 at least 8 metres above the height of any surrounding obstruction
within a 100 metre radius. If this is impractical, aim to mount the turbine as high as possible.
A useful assessment of the quality of airflow at a proposed location can be achieved by
attaching a streamer, similar to a kite's tail, to a pole and letting it fly at the proposed height
of the turbine. If the streamer flies straight, the airflow is clear. If the streamer flutters and
spirals, turbulence is present, and you should consider an alternative site.
Mounting towers can be either guyed or free-standing. Free-standing towers need to be very
substantial and require either a screw pile or concrete foundations. They are therefore
generally expensive. Guyed towers are the more usual choice.

Guyed Towers

A typical guyed terrestrial mount for a D400 would consist of a tubular tower supported by
four or more guy wires. No more than 2 metres of the tower should extend above the upper
guy wire attachment point. The guy wires themselves should be of at least 4 mm in diameter
with a breaking strain in excess of 50 kg. They should be galvanised or stainless steel for
protection against the weather. Shackles and bottle screws should be at least 5 mm in
diameter and where guy lines are looped, the loop should be held with a minimum of 3 wire
rope grips, and should incorporate a thimble to form the eye.
Guy wire radiuses should be observed. The recommended radius for the guy wire anchors
is 0.6 of the tower height.
Four guy wires are preferable to three, as this enables the tower to be hinged up from its
base with three guy wires already in place to support the tower as it ascends.
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