Using a Car Alternator for Your Wind Turbine

For today's wind turbine enthusiast, the core of the turbine is the alternator itself. This component is often the most difficult to construct, and therefore the easiest to decide to purchase. The problem comes when you want to actually utilize the power from your alternator.

Typically car alternators are made to run from about 800 RPM to 7000 RPM or more. Typical wind turbine installations don't reach high into the hundreds of RPM. To bridge this gap, you need to use a pulley or gear system to step the rpm up. But remember, as you go to a higher RPM, the torque you produce goes down. From engineering parlance:

power = torque (times) speed

The power generated at any given time is constant, and the torque si not easily modified, so all you can change is the speed. Using a reduction pulley or gear reduction system is the way to do this. There will be some losses in such a system however and you need to be aware of this. Ideally, you should think about building your own alternator rather than using one from a car. Remember, always use the right tool for the job.