Tire clutch ratio question

[Stormcrow]

The cousin who put together the forging press for me is now working on a power hammer for me. It's a modified Appalachian (Rusty) hammer but using a tire clutch. The ram is 75-100 lbs, with a 3 hp 3 phase motor running it.

Our tire for the clutch is a 19.5" diameter. What should the diameter of the contact wheel on the motor be for an appropriate number of beats per minute for this size hammer?

Much appreciated.

[Mark Wargo New2bs]

pulley ratio calculator at this site:

ratio calculator

hope that helps. That is where I figured mine at.

Mark

[arftist]

From the Little Giant website I know that a hammer that size whants to hit about 200 times per minute. What I don't know is the speed of your motor. Most motors spin at either 1750 rpm or 3600 rpm, roughly. If your motor is 1750, the solution is both easy and simple.
If it is 3600, the difficulty becomes great enough to suggesty finding a slower motor.

Here is how it works. I don't have a calculator so I will round things up or down a bit, but you will understand. The speed of your idler pully (motor pully) will be the motor speed, let's start with 1750 (1800 for easy figuring). Your target speed is 200. Dividing 200 into 1800, we arive at a 9-1 ratio.

Your tire is 19.5" (20) diameter. Dividing 20 into 9 parts gives about 2 1/8". Compensating slightly for working load speed of the motor means a 2 1/4" pulley would be ideal for the lower rpm motor.

At 3600 rpm, the ratio becomes 18-1, Hence the difficulty in application of the fast motor. To use the fast motor, with the 19.5" tire, your idler pulley must be just about an inch in diameter, simply too small to provide sufficient traction to start moving the unbalanced weight of a hundred pound hammer. Of course you could use a jackshaft to effect the greater required gear ratio, however, the added mechanical complexity likely outweighs the difficulty of finding a slower motor.

[Stormcrow]

That was very helpful. Thank y'all!