The 30 kW machine can be either Grid connected or Stand Alone, which means it can sit in the suburbs and supply somewhere between 20 and 40 houses, delivering 240 volts AC or 400 volts 3 phase, or it can be out in the bush connected to batteries, generators, etc, where it's Inverter draws from battery, wind or both and puts out a combined 30 kW max. continuous.
At 40% output, the Pitchwind will generate 288 kW per day. If an average house uses 10-15 kW a day, this will power 20 houses. However, if solar hot water and energy-efficient lighting and appliances are used, the Pitchwind will power 30-40 houses.
The Wind Generator achieves its maximum output of 30kw at a wind speed of 9.5 - 10 metres per second (20 knots / 34.2 km/hr) (see Power Output vs Wind Speed Graph) and has a survival wind speed of 70m/sec, (252 km/hr). It continues to generate power up to 35 m/sec. (See Beaufort scale).
What makes the Pitchwind turbine particularly special is the blade. With the Pitchwind, the blade controls the speed. In other turbines the speed is controlled by power consumption, tail direction or a computer. In the Pitchwind, the outer half of the blade changes its pitch in relation to the wind speed and rate of revolution. This means that the blade cannot overspeed either from lack of load or from windspeed.
This PITCHWIND speed-control solution (see last paragraph) is unique and allows for convenient integration in weak grids and wind-diesel systems. A two-bladed turbine is also more cost-efficient than the familiar three-bladed turbine (except on very small wind turbines).This allows for survival in windspeeds up to 75 metres per second or 270 km/hour.
PITCHWIND is a variable-speed turbine, extracting more energy as the wind speed increases. When the rated windspeed of 9.5 metres per second is reached, the blade pitches to hold the speed constant up to a windspeed of 30 metres per second. From 30 to 40 metres per second, the blades speed drops, with the blade coming to a halt at 40 metres per second.
The blade is coupled directly to the permanent magnet ring generator eliminating the need for a gearbox, effectively reducing noise, maintainence and cost. The variable AC/DC/AC inversion system controls the electrical output and is available as 240 volt 50 cycle or 400 volt 3 phase supply. The IGBT inverter can also draw from batteries connected directly to the DC rail.
The use of windwheels is innovative though based on centuries of application in traditional windmills. The windwheels "yaw" the turbine around to face the wind and are more reliable thanwind direction sensors and computer-controlled motors. As the turbine lines up with the wind, the main blade starts to turn. This design uses the laws of nature to steer it in the right direction.
Installation and erection of the PITCHWIND is relatively inexpensive. The tubular tower and turbine are assembled on the ground. The whole structure is assembled as a complete unit, and is then ready for commissioning. The process can be completed using a relatively small crane.
Because of the size of the turbine, foundation engineering and soil type requirements are relatively modest. Foundations for soil and sand locations require excavation. Setting of concrete footings is completed with an easily assembled base structure.
Rock locations are also suitable for tower sites. These require circular drilling and blasting, and concrete requirements are minimal.
Lattice Tower for Remote Locations
The lattice tower is cheaper to purchase and install than the tubular tower and is often used in remote locations. The lattice tower does not need a mobile crane. All that is needed is a large tractor to position a climbing crane. This device raises itself up by its own bootstraps and is used to build the tower. The crane is assembled on location and lifted into position. The lattice tower components and the climbing crane fit into the same shipping container as the PITCHWIND turbine.
The PITCHWIND turbine is suitable for remote resorts and communities, islands, cattle stations, working properties and developing countries for water pumping and electricity generation. The unit can run in tandem with a diesel generator which it can control. It can be with or without batteries and can accept solar input. As well, it can be connected to a grid situation. This inherent flexibility and economy of the PITCHWIND turbine makes it suitable for a wide range of applications.
Technical Information
Direct-driven generator
The generator is direct-driven and permanently magnetised, eliminating the need for a clutch and transmission and thus improving the unit's efficiency rating. The generator features a three-point mounting so it does not affect the machine bed in the event of temperature fluctuations.Generator maintenance is minimal-virtually non-existent- which is naturally a major benefit. The absence of clutch and transmission frees plenty of space in the nacelle for service operations.
The machine bed consists of a fully-welded, torsionally rigid box-section construction which stretches forwards from the tower towards the wind direction . This construction reduces the load on both the tower and the turbine blades, not least because the blades are routed far ahead of the tower to avoid "impacts" caused by the cushion of air which is always found in front of the tower.
In the machine bed's front end-panel, the generator is installed with three cylindrical studs in such way that the generator's thermal expansion does not apply a load on the machine bed with any resulting constriction forces. The nacelle has two fold-down side-hatches which, when opened, extend the machine bed's floor surface during service operations. This device has been patented.
The yaw control system consists of two fan wheels that drive a worm gear via a chain, in turn driving the toothed wheel rim on the yaw bearing via a gear wheel. The entire system is regulated by the laws of nature, and has shown itself to be the most reliable in operation and guarantees that the turbine always faces the wind as long as there is any wind to generate movement.
