My father in law pulled one out of someone's house (hes and electrician) and asked me if I wanted it. It appears to be a 3 phase voltage regulator like an alternator would have since there are three inputs from the wind turbine. It has a knob that goes from 27 to 37 volts. So, I'm guessing it can be used on a 24/36V setup, although 37V is too low a charge voltage for a 36V system. The top vented part is filled with a few very large resistors. It also has a switch that reads "brake on" / "brake off". It appears to be made by Southwest Windpower.
Other than that, I haven't been able to find much info online about it. Is anyone familiar with this charge controller?
Here is a googled image: