Help in designing a simple transmission system for a wind turbine

[nmenon]

I am considering the idea of making a small scale wind turbine for my final year B.Tech project. I have run into a roadblock, I have to maintain the generator at a relatively constant speed. I was thinking of 2 parallel shafts one from the Turbine blades coupled via a CVT to the shaft to the generator, esplecially when the blades spin slowly. I would like to know whether such a transmission is feasible . It has to be simple and need not be very accurate but it has to maintain the speed of the generator shaft. Other sugestions are welcome. An idea of how to go about it is enough.

Thanks in advance for your help!

 

[BrockLee]

If you take a look at these new bicycles coming out that have a very small means of trans"missioning" the rpm's to torque you can see how easy the designs can be.
My God Its small
/me holds fingers together.
and It looks like it couldn't fit more than two Sprockets inside. well not very big sprockets anyway.

 

[coreyh]

This is a great site for learning about how commercial wind turbines work:
http://www.windpower.org/en/tour/wtrb/electric.htm
I would recommend spending some hours reading on this site before deciding on how to build your turbine.
I think just hooking up a DC motor with and integrated planetary gearhead directly to your turbine (ok, maybe with a small rotary shaft coupling) should work pretty well. You just need to pick the motor and gears so that at the average (or median?) wind speed in your area causes the turbine to spin the motor/generator (when hooked up to it's load, car battery for example) near the peek efficiency of the motor. Using a CVT (or even a multi stage transmission) will just allow you to spend more time spinning your motor near it's peak efficiency. Also, i wouldn't worry too much about trying to optimize your generator's operating condition for low wind speeds because there isn't much energy there. I would use the variable gear ratio's for the higher wind speeds, which contain much more energy. Remember, the power a wind turbine can capture increases with the cube of the wind speed!