I watched some windmills (in Pennsylvania) on a windy day and noticed that they only turned about 40 to 60 times a minute. I know that the speed of the tips of the blades is very fast, but the rpm is still quite low. And yet we know that wind turbines are capable of generating large amounts of power. The generator on my car turns hundreds (or maybe thousands) of times per minute to generate electricity. What is it about the design of wind turbines that lets them generate lots of power at such low speeds? Any recommendations for web sites that describe their design?
