The turbines are designed for strength, simplicity, and low maintenance as the major design criteria

All Westwind wind turbines consist of three blades, up wind of the tower on a horizontal axis and attached directly to a sealed permanent magnet generator. 

Rotor over speed protection is achieved via auto furling. The turbine can also be manually furled at the base of the tower. Furling describes the action of the tailboom pivoting around to be at right angles to the axis of rotation. This action turns the blades out of the wind and thereby reduces power output.

This is a much simpler system than those machines equipped with a steering vane, which we found to be very unreliable in certain gusty conditions (like our local area in the U.K.). It would be difficult and overly expensive to have an electronic yaw control on our small range size. We have opted to remain with the auto furl system, as it has proved reliable since 1984 on all Westwind turbines.

We have no recorded or reported failure of tail booms or associated parts. The 20kw machine has blade pitch control alongside auto furl. This acts like mechanical governors twisting the blades out of the normal pitch when the optimum speed is reached. This results in an incredibly quite turbine in high winds.

The benefits of the Westwind design are as follows:

FEATURE	ADVANTAGE
Auto furl high wind protection	The centre of rotation is slightly offset from the yaw axis, so that in high winds the turbines will turn out of the wind and autofurl. This is an effective protection mechanism that has been used successfully in water pumping windmills for decades. The weight of the tailboom provides a restoring force to turn the turbine back into the wind as the gust passes.
Three Blades	Greater dynamic stability in free yaw than two blades, minimising the vibrations associated with normal operation, resulting in longer life of all components.
Blades up wind of the tower	The blades don’t pass through the turbulence induced by the wind passing the tower. This results in less noise and vibrations.
Direct Drive	Having no gearbox means less parts to wear and less friction to be overcome by the blades. This results in earlier start up in light winds, more power produced, and lower maintenance than designs using gearboxes. With no gearbox our generators run silently this combined with other design features means our turbines can barely be heard.
Permanent Magnet Generator	Our specifically designed Permanent Magnet generators combine high efficiency with simplicity. With the magnets rotating around a fixed stator there is no need for troublesome high-speed slip rings and brushes. A permanent magnet generator also allows the rotor to be stopped and locked in light to moderate winds to enable servicing to be performed.
A Sealed Generator	The generator is sealed to stop the ingress of foreign particles. This reduces corrosion (especially in coastal locations) but also stops the magnets attracting airborne particles.
Manual Furl Mechanism	A lever or winch at the base of the tower can be used to manually furl the turbine. This pulls the tailboom and fin around to 90 degrees and so the blades become side on to the wind. Manual furling enables output to be reduced if necessary and also slows the blades to enable the rotor to be stopped for servicing

Lightwind or Standard Option

Design improvements associated with the Mk2 generator design with greater efficiency and lower start-up torque has removed the need for a light wind option.

STD or Low Temperature Option

Westwind turbines can also be made to suit low temperatures. The STD models are suited to temperatures 0 to 50 Deg C and the low temp versions -30 to 50 Deg C. 

Daily Energy Output 
For design purposes a graph of the daily energy outputs for the various Westwind turbines are available by clicking on the thumbnail above. This can be used for design purposes but should be viewed as an estimation only. The values were theoretically derived from the power curves. Power curves and individual daily Energy Outputs are available on each turbines page (see tabs above).