Bob, here's the speed control I'm using;
http://www.astroflight.com/index.php...products_id=93
The motor is rated at 12 volts, typical, but will tolerate more according to Bob Boucher. I am never at full throttle at the start of a run. The combo has been working well for the past ten years with no signs of wear although they get pretty hot. I'm going to look in to a muffin fan like Tom uses to cool things off. Dan.