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Rotor and hub<br />
CONCEPTUALISATION<br />
The rotor consists of the blades and the hub of the wind turbine. These may well be con-<br />
sidered the most important components of the turbine from both a performance and cost<br />
perspective. This project thesis will focus on selection of blade material, mechanical de-<br />
sign, manufacturing methods, as well as structural and aerodynamic analysis.<br />
Drive train and generator<br />
The drive train is the collective designation for the other rotating parts of the wind turbine.<br />
It usually consists of a transmission, a generator, one or more shafts and bearings that are<br />
all placed in a cover hou<strong>sin</strong>g, commonly referred to as the nacelle. This project deals with<br />
the mechanical design and dimensioning of the core drive train components, taking into<br />
account the unique loading of the wind turbine. The generator is only treated peripherally.<br />
Controls<br />
The control system for a large commercial wind turbine includes wide range of controls<br />
[12, p. 6]:<br />
� Sensors – speed, position, flow, temperature, current, voltage etc.<br />
� Power amplifiers – switches, electrical amplifiers, pumps and valves<br />
� Actuators – motors, pistons, magnets and solenoids<br />
� Controllers - mechanical mechanisms, electrical circuits<br />
� Intelligence – computers and microprocessors<br />
Generally these need to be avoided or reduced to a minimum for the present small wind<br />
turbine that is to be used in developing countries. Relevant components will be treated to<br />
the extent that it is necessary with focus on mechanical mechanisms.<br />
Electrical system<br />
The electrical system of the small wind turbine includes, but is not limited to, cables, trans-<br />
formers, power converters and batteries. These will only the covered peripherally in this<br />
project thesis, as emphasis is placed on mechanical and aerodynamic design.<br />
Yaw system and nacelle<br />
A yaw orientation system is required to keep the rotor properly aligned with the wind. The<br />
design and dimensioning of the yaw system is covered by this project thesis, which also<br />
treats the nacelle construction.<br />
Tower and foundation<br />
The tower of the wind turbine carries the nacelle and the rotor. This project thesis deals<br />
with tower design and dimensioning. The supporting foundation is not treated thoroughly,<br />
as knowledge of local soil properties is a requisite to the design of small wind turbine<br />
foundations.<br />
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