PTO step up: 540 to 3600 RPM

[davel8257]

Generators, power washers, car alternators, hydraulic pumps, air compressors typically do not operate at 540 RPM -- they are designed to attach to a 4-cycle engine. I'd like to build a multi-purpose, 3pt platform with a step-up system that provides a 4-bolt interface and an output shaft turning at around 3000 - 3600 RPM.

I think I'd choose belt drive (for some 'give'). I think I'd choose a 1:10 ratio -- my Kioti's PTO hits 540 RPM at 2500 RPM (engine tach). I'd rather 'idle' down to around 1500 RPM, consume less fuel, less noise (& less power -- all I want is 'lawn mower' engine output). At 1500 RPM, the PTO is turning around 300 RPM (5:1 ratio). I'd want to step the 300 RPM up to 3,000 RPM or so. A 1:10 ratio step-up (like a 12" pulley driving into a 2" pulley). Pillow block bearings, 1" shaft stock, milled key-ways....

Has anyone tried something like this?

I've seen posts that comment on fuel consumption (higher on a 45 HP tractor than a 5HP lawn mower engine), etc... but I think I'd rather not have the extra engine sitting around requiring maintenance, not starting when you need it, etc...

 

[CalG]

Do it in two hitches, that is a 3:1 and then a 3.3:1. With some engine-uity the shafts can run concentric.

Had a pull behind snow blower done up that way. Chain drive... the drive worked fine, the blower...? Not so well ;-)

 

[BeezFun]

If all you really want is lawn mower engine output, you could use step down pulleys like they have on large drill presses and other shop machinery. That would give you a wide range of output rpms in case you run into some other requirement down the road.

 

[davel8257]

That's a good idea. I like the idea doing two stages. Still not seeing the time in my schedule to work on it yet...

 

[buickanddeere]

How much are you trying to save? If this equipment is running 24/7 then sure the investment will eventually pay off. For a few dozen or even a few hundred hours a year. The pto and stepup drive is a curiosity and hobby project rather than being practical.
eBay lists 540 to 1800 gear boxes. Odds are the same manufacture makes 540 to 3600.
Safety is another factor as 99% of these projects have exposed whirling belts, pulleys and shafts that are obvious and nobody should get maimed or killed with. Yet hospital ERs do a brisk business with mangled and missing limbs.

 

[buickanddeere]

I was just thinking of all those noisy low end pto powered standby generators with a 540/3600 gearbox. Could probably find a used generator , remove the gearbox and sell the gen head to somebody wanting to direct couple it to a 3600rpm small engine.
Odds are that would be cheaper than the parts alone to cobble together a 1 to 8 drive.

 

[BBoudreaux]

PTO turns opposite direction of engine, does that matter to you?

 

[xzcVAbc5]

How about a hydraulic motor?

 

[davel8257]

How about a hydraulic motor?

I thought about that, but they seem to be offered in low rpm high torque situations. I'd still be looking at pulleys & belts.

 

[Tractor Seabee]

Stay away from small pulleys. A 2" is hard on belts and has a lot of loss as you are only contacting a small segment of the circle. Start with at least a 4" on the higher speed shaft and work up. hat is where a 2 step arrangement pays off on keeping the profile down. In all not very practical. Look in the Surplus Center Catalog on page 71; they have a hyd motor that does 3000 RPM for $178-$220 depending on HP output. I doubt you cold gather all the materials for your pulley arrangement for that.

Ron