1. The Proven 15 kW turbine; designed for reliability and performance
EWEC Athens 2006, CW32.
Small wind turbine systems.
Proven Energy Ltd., Johnnie Andringa

2. Next 15 minutes Products & company Turbine design & safety
15 kW blade development
Blade material
Moulds and process
Blade tests
Further Development
Turbine performance
Status

3. Products
First turbine Rannoch Moor, now, 17 years later still up & running
2.5 and 6 kW
Transition from off-grid to on-grid
Household and professional customers

4. Company Based in Scotland; high winds and many remote islands
Export to over 30 countries
2005; 150 turbines, growing over 50% year on year

5. Turbine design Simplicity: reliability Direct drive
PM generator, no rotating coil
Brake disk
Downwind, passive yaw
Low rpm; tip speed < 65 m/s; low noise

6. Safety mechanism Passive pitch: elastic hinge with prestressed springs
Blades cone downwind

7. 15 kW development Same concepts as smaller turbines Basic numbers:
9.5 m diameter
95 …160 rpm
rated 11 m/s
Blade: twintex; 15 kg each
Development started 3 years ago

8. Blade development 2.5 kW; full PolyPropylene as blade material
Tough and non-sticky
6 kW; wood epoxy
Manufacturing of larger shapes
Vulnerable (impact)
15 kW started with glass-epoxy
ended with twintex (Glass with PP matrix)
As above and ‘recyclable’; melt PP from glass
However; ‘NEW’ material and process

9. Moulds
Elevated temperature; expensive moulds

10. Process
Filling of mould
Blade has a rib
Vacuum forming in oven

11. Blade testing Hinged blade; low bending moments (IEC)
Static tensile & bending test
Same design, same mould
Improvements in production
Over 3-fold increase in critical strength
More consistent quality

12. Further development Hub, Generator, Controller, Automatic brake
Covers are designed; styling of turbine

13. Turbine Performance Theoretical / experimental analysis of springs
Optimise power curve and safety mechanism

14. Status PERFORMANCE was achieved early
Establishing RELIABILITY took longer,
especially with new production process
Now entering final 6 months live cycle test
Full scale production starts 2007
IEC 61400/2 standard and procedures helpful