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9. Tower
Seite 24
| Owners Manual SkyWind NG, Version 5.1
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9.2 Decoupling your tower for mount on buildings/structures
Every rotating machine exerted to the forces of the wind should only be connected to a house
or rooftop structure via a decoupling system. Otherwise loud noise may be heard within the
building upon operation of the wind turbine as the tower (and rooftop) will bend slightly under
gust load and spring back once load decreases. This spring action will also decrease the wind
turbines lifetime due to material fatigue. A decoupler must be stiff enough to keep the tower
vertical under normal operation but soft enough to prevent spring action of the tower and the
transmission of noise into the buildings structure. A decoupler must:
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be of a total decoupling type; meaning the wind turbine must be mounted entirely in (for
example) rubber. No additional structures, tension ropes etc. are allowed. The turbine must be
totally decoupled from the building
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isolate both noise–
and vibration from the buildings structure
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ensure dampening and isolation for all forces the turbine can exert on the tower
When planning your decoupling system you should consider the hardness of the damper
(shore), the structure the system will be mounted to (concrete, wood, plywood, steel etc.). The
lever of the planned tower length its weight etc. also have to be taken into account. For examp-
le: For 2 m long steel towers of 60 mm diameter with 3.2 mm wall thickness three type V
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15
anti
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vibration mounts (picture right) by ROSTA (Swiss) are often the best solution.
Each installation must consider the turbines operating frequencies of 10
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50 Hz. The tower sys-
tem must never resonate.
If installed on a standard roof distance should be kept to chimneys, stair treads on the roof or
bedrooms directly below the roof. When installed correctly the turbine will be very quiet but it
is impossible to be absolutly noiseless. Consider changing the storm control shut
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off voltage to
lower values (e.g. 35
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40 V) to further reduce gust loads and rpm
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making the system even
more quiet. Consider installing the sound control system.
Under no circumstances is it allowed to fix a decoupled tower (e.g. with tension cables, guy
wires etc.). It is perfectly normal that a decoupled tower will slightly move with the wind under
gust forces—this is what makes it quiet. However it must no vibrate/resonate.
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Noise/vibration decouplers (V 15) by ROSTA
GmbH of Swiss are maintenance
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free and safe
