Hey guys, I'm working on a project involving a DC motor. I'm in school for mechanical engineering.. Electrical problems haven't really interested me so this is the first I've ever really looked into it apart from studying basic circuits in a physics course last year. Anywho, the project: I want to power and control a 2.5 HP, 120 volt GS Electric DC motor (part number 119022 if it makes a difference). The motor was taken from a treadmill along with anything else of electrical importance. However, I don't want to use the old circuit boards because they're probably damaged and they do several other things besides power the motor. The motor says its speed is 5600 rpm and I want an rpm adjustable from the range of 80 to 250 rpm. I don't know how the powerband of electric motors works, but if it's anything like a combustion engine, it won't perform well that far below 5600 rpm. I may have to gear things differently as opposed to using the shaft directly from the motor if that's the case. How are DC motors generally powered? Could a lamp dimmer be used in this to navigate to different rpm's?