21-03-2003

Renold Clutches & Couplings have been chosen to provide one of their proven sprag clutch designs for use in Wind Power Turbines, allowing major advantages over competing designs. The supply of an overrunning clutch in a 'Cardan Shaft' arrangement in combination with a Vee pulley has permitted new technologies to be delivered.

Wind turbines are unique in the power generation sector, because the working fluid, i.e. air, cannot be controlled before it reaches the turbine. In high wind conditions, conventional fixed speed turbine systems need to contend with large torque fluctuations and this causes power output variations by up to 100%, through the generator.

The new turbine system design allows rotor speed variation coupled with change of blade pitch angle, and via a unique gearbox and clutch combination, this leads to generator output power being maintained at a constant level, regardless of wind fluctuation conditions. In cases of overspeed, the rotor reaches fully feathered position and cuts out, however the clutch allows the generator to continue running.

Conventional systems require extremely robust and heavy assemblies in order to contend with the large fatigue loads. The new design, which incorporates a swept blade diameter of 33m and can attain speeds of 50 rpm, is about 50% lighter than conventional wind turbines providing improved power to weight ratio and overall cost effectiveness. It also allows for excellent operating cost reduction, as only 3% of rated power is consumed within its components, while reliability is increased because of the use of simple, quality components.

The project yet again underlines Renold's commitment to advancement of future technologies, working in partnership with customer requirements.

For further information, please contact:

Renold Clutches & Couplings
Wentloog Corporate Park
Newlands Road
Cardiff
CF3 8EU

Tel: +44 (0) 29 20792737
Fax: +44 (0) 29 20793004
Email: couplings@cc.renold.com