Where to source a front PTO

[r8f1k]

Looking for a front PTO that will run a finish mower. I have an output shaft on my crankshaft that is 18 spline - 1" (25mm) and a straight shot to the middle of my current 3 point hitch. I see that Zuidberg has them, but they won't sell you a box unless you bought the 3 point from them. Looking for a unit that can handle 40HP, 540 output, electric clutch to turn on and off. Thoughts?

 

[KWentling]

I had looked at Zuidberg for a 3-point and pto for Kubota M7060. About $10,000. Couldn't justify that so built my own with an under the tractor PTO shaft, which I know you wan't to avoid.
You're going to need to determine a gear ratio to reduce the RPM to 540 or 1000 depending on the mower requirements and also the direction of rotation. Going to take a healthy electric clutch for that much torque. Maybe you should consider a hydrostatic drive arrangement. You might call Surplus Center. They carry hydrostatic components as well as gearboxes. They might be able to recommend something.

 

[r8f1k]

Hydrostatic, can you elaborate? The reason I am against an under the tractor drive shaft is that I will still need a rear PTO

 

[CoyPatton]

Looking for a front PTO that will run a finish mower. I have an output shaft on my crankshaft that is 18 spline - 1" (25mm) and a straight shot to the middle of my current 3 point hitch. I see that Zuidberg has them, but they won't sell you a box unless you bought the 3 point from them. Looking for a unit that can handle 40HP, 540 output, electric clutch to turn on and off. Thoughts?

Might be simpler to go with a hydraulic drive mower and source a hydraulic pump and reservoir to run off the front PTO. Skid steer mowers would fall into this category, but probably require more flow than a single pump would generate.

 

[KWentling]

Understanding hydrostatic transmissions | Hydraulics & Pneumatics
It's basically a closed system. A pump (probably a variable flow piston pump) would mount to the engine shaft and drive a fixed displacement motor for the PTO shaft. There would also be a small charge pump to keep the main pump from cavatating. Some of these setups are all in one assemblies and others are separated connected with hoses or steel lines. Finding something suitable would be the trick. I thing newer ag combines use these drives on rotors and fans.
I have seen components at Surplus center before but all they show at this time is hydrostatic axles. This may be too expensive, complicated, and bulky for the front of a small tractor. It would take some investigating.
QUOTE=r8f1k;5767407]Hydrostatic, can you elaborate? The reason I am against an under the tractor drive shaft is that I will still need a rear PTO[/QUOTE]

 

[KWentling]

http://www.metaris.com/pdfs/HG_Sundstrand_20Series_Catalog_2013_web.pdf
Heres the components it would consist of. Would take some studying to see if there is a combination here that would work for you. The pump would be
"destroked" when in neutral and then in forward (or reverse depending on the rotation you would need) to mow.

 

[r8f1k]

Call me hydraulic dumb.....I think I understand the diagram, but do you have a list of what I would need? Based on what Metaris has to offer, I would not know where to start with what to buy.

 

[KWentling]

You have to know the rpm of the engine for the start point and the needed output rpm for the mower, engine hp and mower required hp. The formulas for flow are pretty easy to grasp. I'm pretty well versed in cu.in. Not so much dealing with metric volumes, so lots of converting to be done. I suggest you get all your information together and call them. I'm not pushing you towards Metaris, it was just the first supplier I clicked on.

Call me hydraulic dumb.....I think I understand the diagram, but do you have a list of what I would need? Based on what Metaris has to offer, I would not know where to start with what to buy.

 

[r8f1k]

You have to know the rpm of the engine for the start point and the needed output rpm for the mower, engine hp and mower required hp. The formulas for flow are pretty easy to grasp. I'm pretty well versed in cu.in. Not so much dealing with metric volumes, so lots of converting to be done. I suggest you get all your information together and call them. I'm not pushing you towards Metaris, it was just the first supplier I clicked on.

Engine working RPM = 2,000-2,200. Even with the mower running and AC on, it mows with no problem at 2,000 RPM
Mower requires = 540 RPM
Engine HP = 45
Mower required HP = 32

 

[ericm979]

You'll need 26 gpm @ 2100 psi for 32hp. (the calculator is on metarsis's web site). While you can drive a lot of power through a belt (see for example dragster superchargers which eat hundreds of HP), you'll need more than 1 standard v belt for that. Like 3 B/BX series belts according to Baldor's engineering specs. I'm dubious that the engine is designed to deliver most of its power through the front end of the crank.

The Matarsis PTO thing has a fixed displacement pump and a variable displacement motor... otherwise known as a HST. That's not perfectly efficient. The drive itself will be consuming ~15% of the power. So to get 32hp at the mower you'd be taking 36.8 hp from the engine. That's not leaving much to move the tractor. Of course the mower probably does not need 32hp most of the time, just in the worst conditions. You'd have to slow down then, or more likely the mower will struggle more in thick grass than it does now.

Of course even the 3pt hydraulic power pack and motor on the mower that I'm suggesting is not perfectly efficient. Having a fixed displacement motor may be no better than an HST, or it may be somewhat better but not as efficient at a PTO shaft.

You have two threads about this. It'd probably be more useful to you to have them merged. In the other one you said that you won't be running the sprayer and mower at the same time. So I'm puzzled why you'd be going through all this work to make the mower not run off the rear PTO.