Anyone know of a good way to reduce the rpms on a motor (exploring both gas and electric options) down to about 200 rpm with some degree of speed control say between 150-250rpm?
The end application will be used to wind up electric fence wire back onto spools. So the motor needs enough power to pull about 1/2 mile of light gauge wire with 10 lb weight tied to the end to keep the wire straight.
If I did the math right 200 rpm should be a good speed to turn the spool. I think a 1hp electric motor would have plenty of power (actually a 1/2hp would probably do it) with the needed rpm reduction. So right now I'm considering 3 different approaches: a small gas engine (have an old 5hp briggs) with a reduction gear box. (new gearbox is about $150), an electric motor with reduction gearbox (would need both motor and gearbox ~$200-250) would have to drag around a generator to use and speed control on single phase motors could get complicated, and last a gas over hydraulic setup (small gas engine running a hydraulic pump).
The hydraulic setup would be the easiest to use and also the most expensive (unless I can find the pumps and hoses on some old equipment somewhere). So I think my best route would be the gas engine with a gearbox of some kind. Any suggestions on where to find a gearbox or transmission with a ratio between 10:1 and 20:1? I've been looking at go cart torque converters but I don't think they have the needed ratio. What else would use a ratio like I need?
Does anyone make a gearbox that would bolt up to a 5hp engine (seems like most engines this size use a 3 5/8" bolt circle)?
What ideas do you guys have?