I have limited time to access the inter-web these days but do know there are CNC routers and mills that have been built using these, running on 12V or 24V. Basicly controlled as a BIG stepper motor. I believe original Voltage was 55V,(what the motor saw). Just thought I'd ask as I see little point re-inventing the wheel unless I'm going to go sideways.
Place up the road from me has been turning them into generators for years http://www.ecoinnovation.co.nz/

Just went for a look, see sites changed a lot since last visit, will leave till I get time .