Patent CA-2477595-A1 (CA)
Title: An auxiliary propeller rotor for horizontal wind turbine generators
Inventor: MATHIEU ALFRED L
IPC: F03D9/34
Filed: 2004-08-23
Abstract: 1. The Auxiliary Propeller Rotor for Horizontal Wind Turbine Generators, "Booster/ Stabilizer Props" technology applies to up-wind, and downwind turbine generators. The invention consists of adding an auxiliary rotor having two or more propellers on the extended shaft or axle of the turbine, with the main rotor having two or more propellers, having an allocated space between the two rotors.   2. The space between auxiliary rotor and the main rotor on the extended shaft or axle of the wind turbine generator is 12-18 inches/30-45 cm, more or less.   3. The auxiliary propeller rotor and the main propeller rotor are secured on the same shaft or axle of the wind turbine generator and rotate together, from the energy of the wind, either clockwise or anti-clockwise.   4. The extended shaft or axle of the turbine generator is shaped multi-sided, such as hexagonally, to allow easy adjustment of the most advantageous circumferential arrangement between the auxiliary and the main rotor propellers. Essentially, there are 6 settings between the two so that the propellers are not necessarily in line with each other but can be offset so as to achieve maximum power output from the wind energy.   5. The auxiliary rotor with its two or three propeller blades, more or less, synchronized with the main rotor with its two or three propeller blades, more or less, results in significantly greater output, with its lesser blade diameter than the standard one rotor with two or three propeller blades on high tower wind generator turbines.   6. The auxiliary rotor propellers and the main rotor propellers that are on the same extended shaft or axle of the wind turbine generator, permit many variations of the propellers such as each having the same or different length of blades, widths of blades, and number of blades, (3 to 5, more or less). This plurality of propeller blades on two adjoining rotors with one half the blade length has the same power output, more or less, as a standard rotor with two or three blades with twice the diameter on a high tower supporting the wind turbine 7. The logic is that the blade length of propellers on two spaced rotors on the same shaft or axle is doubled, more or less, and is equivalent to one rotor with twice the diameter of the propeller blade. For example, a high output turbine wind generator with a tower height of 50 meters has a one rotor 3 propeller blade diameter of 30 meters, it can be substituted with two propeller rotors each being 15 meters in diameter and the height of the tower can be reduced by one half, to 25 meters more or less.   8. The auxiliary propeller rotor allows a lower tower height resulting in lower costs tower construction, and easier to do repairs when needed. The fabrication cost of the shorter blade propeller is also much less than the longer blade that requires special alloys to withstand the additional stress.   9. The invention of the "Auxiliary Propeller Rotor" has the following objectives: - to significantly reduce the height of the wind turbine tower, - to increase the effectiveness of capturing the thrust of the wind energy, - to increase greater electrical output at low wind speed, hence lower startup speed, and ideal for low wind velocity sites.   10. The technology to slow down the rotation of the propeller blades of wind turbine generators during high winds are varied. Several high output turbine generators have a feathering mechanism on the single propeller rotor, similar to an airplane propeller rotor, that rotates the blade of the propeller to have a lesser resistance to air.      The old fashioned wind vane which swivels the propellers and turbine obliquely to high winds is still an effective and simple way to decrease the speed of rotation during high winds and is the recommended feature for the "auxiliary rotor" on a wind generator turbine. It is simple, easy to repair, and will not unduly delay electrical output.