All right here is what this thread is good for. Good old solid truth.
I've been looking at a little military surplus induction generator. It was probably used in air craft or something. I'll try to explain it the best I can.
The thing is very simple. It has a stator just like a motor, looks like two phase. The interesting part is the rotor. It looks like a little copper cup or perhaps a thimble. It's about 3/4" diameter, 1" long. Has no electrical connections to it.
What happens is a signal or AC power is fed into the stator and the copper thimble rotates within the magnetic field. The field rotates at certain RPM. The thimble must rotate faster than the field. The effect is that the AC power is amplified.
It looks like these special type of generators are used in power plants, wind turbines, etc. They take the electricity from the power grid and amplify it. This is the simplest way to feed the power grid I have ever seen.
I think of it as a rotating amplifier.
Here's the wiki (sparse as it is)
http://en.wikipedia.org/wiki/Induction_generator (http://en.wikipedia.org/wiki/Induction_generator)