African Wind Power 3.6m diameter wind turbine
Here is some further information about the 3.6.  See also the Powervision page. The wind turbine is available in battery charging format for 12, 24, 48 or other voltages as required.  A high voltage version with transformers is being tested.  Pumping versions are planned.



"Nothing tells you more about a wind turbine's potential than rotor diameter."
- Paul Gipe
-Wind Energy basics, Chelsea Green 1999

Power curve


Here is the nominal power curve for the 3.6 machine.  Power curves vary between different voltages, and there have not been sufficient funds to produce a complete set of data, but we are working on it.

Notice that the diameter of the machine is large compared to it's maximum power output, and this gives it the torque to deliver good power in lower windspeeds, when other machines are unable to catch as much wind.  We believe it is more important to have a steady, day to day supply of amphours into the battery, than to have a  high peak-power rating.




This is a 'heavy metal' wind turbine, built for low speed and long life.  In this picture you can see the alternator (black) and the 3 blades (white). The tail had not yet been attached to this unit.  Assembly usually takes place at ground level, and then the tower is erected using a simple hand hoist (Tirfor).  The tower is supported by steel wire guy ropes.

Evolution
First built for Zimbabwe Energy Research Organisation (ZERO) by Manx Wind Energy Services (consultants) in 1996, the wind turbine design was commercialised by African Windpower of Harare and badged the pt3600.  Detailed design has been by Scoraig Wind Electric throughout. 
The wooden blades of the original were replaced by fibreglass, and the tail was simplified.
On the left is a 1999 production unit from Powertronics.  Tens of machines have been produced for local customers in Zimbabwe and the export market.  With the new African Windpower factory, production will be stepped up.  A 5.5 m diameter machine is actively under development.  Smaller machines around 2 m diameter, will be available later.(click to see larger image)
 


Here are parts of the alternator.  The magnet rotor (top left) is cast from iron.  It runs on the main shaft.  The blades are bolted to the face this rotor.  Inside the rotor are ferrite permanent magnets.  The magnets move past the laminated core of the stator which contains stationary coils of copper wire.  On the right you can see the stator being wound.
The alternator is heavy because it has many magnets and coils in it.  Lighter alternators generally run at higher speed.  These lighter wind turbines are noisier and  wear themselves out sooner.



 

Click to see an enlarged picture. The wind turbine is protected against high winds by a simple, passive system which has been tested in winds exceeding 100mph, without incident.
As wind grows stronger, and maximum power is reached, the turbine is 'yawed' sideways from the wind.  This prevents the blades from overspeeding.  There a minimum of moving parts involved.. no springs.. no highly stressed components.(click)


Mick Sagrillo writes about the AWP 3.6:
This is a very simple machine that does what it is supposed to do.  It is quite heavy duty and build to last a long time.  The turbine is easy to install, with simple tools.  I am most impressed with the turbine’s slow speed and quiet operation.  It is refreshing to see that a modern wind generator can be manufactures that is absolutely quiet in its operation.

 This is a very nice machine.  I only wish someone in the US
could build something as good as the AWP.  We could use the competition, to
say the least.  And the low speed reliability.  This is heavy metal, which
is right in line with my ideas on wind turbine design.  Nice job!!!


awp todayThe AWP website in 2009