An Idea Whose Time Has Come

[David Devuono]

Heck I just mow twice as fast. If its a light cut I move to a higher gear. Neigbour (real farmer) must have had a chuckle as I bounced across the field at 20MPH. Got the job done though.

 

[wcampbell47]

Recently I used my PTO tiller to make a new garden in extremely hard dry soil. I needed the power delivered at full rpm's to get the job done.

My own garden has multiple truck loads of bank sand that I have tilled into the south texas gumbo. I run the engine at something between 1600 and 2000 rpms which delivers more than enough power to turn the tiller.

Mowing ... obviously I get a better cut when the blades are spinning at the rated rpms. I could see the benefits of a multi speed PTO.

Now comes the kicker. On my B7510 shifting the PTO into 540 turns the rear pto shaft. It has a mid pto that runs at 9600. When shifted into the 9600 both shafts (rear and mid) turn. Just for grins I have shifted into the 9600 while attached to my land pride finish mower. The engine lugged and strained when I tried to mow. I stick to the 540 shaft speed and run at about 2000 rpms for light duty mowing.

 

[Redneck in training]

You don't save half fuel running on half throttle while moving. In fact you might use more fuel. There is a balance between engine power and power required to turn your mower. If you look at the power, torque and efficiency curves for your particular engine you will see that most engines are geared such a way that they deliver maximum torque and have the lowest specific fuel consumption (oz/HP) at or in vicinity of the PTO speed.
If your mover requires 15 HP to cut your grass the speed governor will adjust the fuel delivery so the engine will deliver exactly the power required.
Running at too low speed while the engine is loaded might be bad for bearing. There is certain minimum linear speed of the shaft relative to bearing that will provide separation of the shaft and the bearing by oil film. The higher speed the higher is the load the bearing can handle. Think about aquaplaning. At low speed and high load the oil film might be penetrated and the shaft touches the bearing causing wear. Think about lugging the engine.

The conclusion is that the fuel delivery is proportional to the power required to run your load (mower) adjusted for efficiency at particular speed. I would bet that you will use less fuel at normal PTO speed.

 

[CalG]

I can see some reasoning behind a variable output speed PTO.

'Would be handi for the "suburbanite".to run things at a "comfortable pace".

But many owners look at the PTO Horse Power as a means of assessing the unit's potential to do the task required.
A Variable speed drive, Especially a Hydro Static unit SUCKS HP and turns it in to heat. I'm not paying a premium for that! What would you say if you bought a 100 HP tractor that only put 55 HP to the PTO? Not much I bet.

A multi SPEED gearbox for the PTO might be a good deal. (Some makers offer at least three) But then, would some fool blow up his baler or throw a blade into the next county??

The 540 and 1000 "standards" ( I know, there is everything between) seem to answer most needs.

You could whip up your own if you really needed too. Vickers makes some nice units.

 

[blueriver]

If that is the case with your mule you should have a set engine speed marker on the dash boards tachometer that gives you the proper engine speed setting for the conversion speed for the towed implement

Thus therefore my confussion. I have one tach mark at the 2600 rpm for the 540 ... nothing for the 1000. This thread is bothering me so last evening I went and visited my old retired neighbor farmer and we talked about this.

He stated that equipment has been designed for either 540 or 1000 not both ... he had a no-till drill that was 1000 and on his JD tractor his pto shaft was 2 shafts ... one for 6 spline 540 and the other for the 1000 ... a 1000 gearbox is geared to match the equipment and the tractor to run at rated rpm ... thus you run a 1000 at the same engine rpm to avoid lugging the engine and run the gearbox ... also stated if you like go ahead and just run your 540 equipment at 1000 with half throttle and lug the engine and burn up bearings.

Just saying what he was saying ... and sometimes we can learn from the old timers. So ... I' think I'll run 540 at 2600 for the equipment I have ... If I ever get a 1000 piece I'll use that.

 

[Mark Page]

Sounds like a good idea if you have sufficient power. I'm pretty sure my 45 horse Massey would do it if all I'm doing is mowing with a 7ft finish mower.
The old farmers say gear up and throttle down.

 

[oldnslo]

Thus therefore my confussion. I have one tach mark at the 2600 rpm for the 540 ... nothing for the 1000. This thread is bothering me so last evening I went and visited my old retired neighbor farmer and we talked about this.

He stated that equipment has been designed for either 540 or 1000 not both ... he had a no-till drill that was 1000 and on his JD tractor his pto shaft was 2 shafts ... one for 6 spline 540 and the other for the 1000 ... a 1000 gearbox is geared to match the equipment and the tractor to run at rated rpm ... thus you run a 1000 at the same engine rpm to avoid lugging the engine and run the gearbox ... also stated if you like go ahead and just run your 540 equipment at 1000 with half throttle and lug the engine and burn up bearings.

Just saying what he was saying ... and sometimes we can learn from the old timers. So ... I' think I'll run 540 at 2600 for the equipment I have ... If I ever get a 1000 piece I'll use that.

The Old Timer is correct. All Ag equipment I have seen and used is either 540 or 1000 RPM. On every tractor I have driven the Engine RPM to achieve these speeds was the same position on the tach. Some equipment like a hay elevator I never ran at rated speed while a forage harvestor/chopper I ran the engine full throttle since I wanted max power to the PTO.

Yes IF you have enough HP you can buy shaft adapters to convert from 1000 RPM spline down to 540 RPM spline and run your engine at half throttle to obtain the 540 RPM on your PTO.

Example: 200 HP tractor running a conventional small square baler that a 50 HP tractor could operate.

Roy