C&F Green Energy Wind Turbines feature many benefits unique to small wind turbines.
Active Blade Pitch System
Turbine speed in controlled by an active blade pitch system. A state-of-the–art control system has been developed to ensure precise rpm control even in the absence of any generator torque. Hence, optimal energy capture is ensured in all conditions. This enables the turbine to start producing at low wind speeds, and continue through to very high wind speeds by changing blade pitch to maintain optimal machine speed. This is not achievable with a stall controlled machine where the blades are intentionally operated in a stalled condition, resulting in fatigue, noise and poor performance. The active blade pitch system achieves optimal efficiency and results in very quiet operation. In addition, the pitching system serves as an emergency brake, rapidly stopping the turbine in the case of an emergency. The pitch control actuator is of a roller screw design. Extensive testing has identified this device as the only suitable component for this arduous application. In fact, this device is so robust that it used in many military applications. Although expensive, extensive field experience has proven the reliability of this the roller screw in the wind turbine pitching application.
Active Yaw Control
A purpose built microprocessor monitors the wind vane and the anemometer on all C&F turbines. This directs the yaw or slew motor, allowing the turbine to be optimally aligned to the wind. Not only does this improve efficiency and reduce noise but it also reduces fatigue loading on the turbine. Yaw brakes are employed to provide sufficient damping to prevent knocking of the nacelle gearing which can arise from non-identical loads on the blades thus protecting the yaw gearing system. The 24V slew motor is connected to a long life gearbox to drive a spur gear on the nacelle yaw system. This system affords significant advantages over a worm drive which is more commonly used in turbines of this size.
C&F Green Energy work with a leading blade design company in Europe to design and build blades in-house. The large selection of aerodynamic blades within the product range allows each turbine to optimise the swept area, efficiencies and output. Larger blade shells are made from structural glass fibre and epoxy resin and are joined using a central shear web and epoxy glue and finished with a two pack durable paint with provides excellent environmental protection. Smaller blades are manufactured from structural glass fibre and vinyl-ester resin using a unique fabrication method whereby the outer shell fibre structure is wrapped around the blade without any split. Hence, structural integrity and strength are greatly increased.
All turbines are fitted with a fail-safe brake mechanism to ensure controlled shut down in the case of an unforeseen event. This is a secondary braking system in addition to the primary blade pitching method of braking. Three spring loaded callipers operate on the rotor brake disk to achieve a controlled shut down of the turbine. In the unlikely event of a total systems failure, the brakes automatically engage and furthermore, prevent the turbine from restarting until so instructed by the controller.
The failsafe rotor brake system is opened using a hydraulic system where an accumulator is employed to prevent cyclical pump operation. In the case of an emergency braking situation, the accumulator charge is instantly dumped to allow the brakes to activate.
Yaw brakes are designed to provide sufficient damping to prevent the knocking of the nacelle from non-identical loads on the blades thus protecting the yaw gearing system.
The microprocessor on each machine is GSM linked, so that data is continuously relayed back to the Galway based monitoring centre. In the event of a fault, it will be immediately and automatically diagnosed at our control centre which operates on a 24 x 7 x 365 basis. During extreme weather, the turbine can be remotely shut down.
Low Carbon Concrete
where available, particularly in the case of foundation installations for our 50kW to 100kW range, C&F Green Energy use Low Carbon GGBS Concrete (GGBS: Ground Granulated Blast furnace Slag). this cement is a recycled product. It is more environmentally friendly and has a much lower CO2 footprint than CEM II or CEM I cements..
The hyper efficient generator is manufactured in-house using a permanent magnet, radial flux design. This type of generator has several advantages including its compactness and its suitability to air cooling. Each coil is sealed in epoxy and can be individually replaced.
Grid Spring Coupling
The generator is connected to the rotor shaft by means of a flexible coupling. This helps protect the generator from the inevitable torque fluctuations which occur in wind turbine applications. Through extensive testing, an optimal coupling design has been identified. The grid spring coupling was originally developed for the demanding steam locative application and it has proven uniquely suitable and reliable for the modern direct drive wind turbine configuration.
When required, a variable speed fan is engaged at high ambient temperatures to ensure optimal generator operating temperature.
Every component in a C&F Green Energy wind turbine is either manufactured in-house in Ireland or sourced from best-of-breed suppliers.
All masts up to and including the CF25 can be raised and lowered hydraulically, which greatly simplifies installation and service.
Marine grade corrosion protection as standard.
This combination of features, coupled with superior build quality, allows C&F Green Energy to produce some of the most efficient and cost effective turbines in the industry.