HST/ PTO SPEED

[J_J]

This is what I found for the L3240 32 HP engine, and 26.5 HP PTO

Kubota L3240 - Specifications - Attachments

 

[Transit]

If your tractor is rated at 32hp (HST) and 25 hp at the pto is that all the time, even if the tractor is sitting still using ,like a winch? or is it diff. like running a mower with the tractor moving? By moving in the tractor does that change the pto hp or by keeping it at 540 gives you the 25hp?:confused2:
thanks Scott

Hp is a bit more complex than RPM alone, there is also the matter of torque.
Torque x rpm / 5252 = HP

You can see that if you keep hp constant, as the torque increases the rpm's will decrease.
Keep the revs constant and hp follows torque.

Another way to look at it, set the engine revs for 540 rpm at the PTO with no load. The hp developed is 0 because the torque is 0. As the PTO is loaded only the torque will change, increasing to meet the loading and hold the revs at 540.
At some point, the PTO revs will drop as the load is increased, this is the point that the engine can sustain the rpm's and torque that will produce maximum hp under those conditions. In your case 25 PTO hp @ 540 rpm.

 

[First one]

Thanks for the help:thumbsup:
Ok ,one more thing ,whats the deal with gross hp which is 34hp and net hp which is 32hp?

 

[J_J]

Net horsepower ratings is the measured output on an engine with all peripherals attached. Hyd pumps, alternator, water pump, etc.

Gross HP is measured at the engine flywheel..

 

[hawkeye08]

Thanks for the help:thumbsup:
Ok ,one more thing ,whats the deal with gross hp which is 34hp and net hp which is 32hp?

gross hp is what they charge you for and market the tractor with. Net hp is what you have available to do work with after you buy it.

 

[J_J]

Sort if like on your paycheck, first thing you see is gross, and at the bottom is the net after all the deductions are taken out for the government.

 

[First one]

Well, that cleared that up fast ,you never get all you pay for or work for I see even in the tractor world thanks again!!

 

[Soundguy]

I think with a hydro transmission the pto is independent.??

So, I think your pto will always be rated 25pto hp, though don't take my word for it.

Man, I wish I had 25ptohp. I got 20ptohp.

not how that works.. ind pto is just ind of the drivetrain or dt clutch.. engine rpm still dictates pto speed and hp..

soundguy

 

[dfkrug]

gross hp is what they charge you for and market the tractor with. Net hp is what you have available to do work with after you buy it.

Note that Kubota went to net hp marketing a while back. Your L3130
has 31 net hp, while gross is 32.1hp. Most tractor makers don't do
it that way....kudos to Kubota.

BTW, your tractor makes 25.5hp at the PTO, unless you have a HST;
then its only 24hp. 1.5hp is to run the charge pump.

 

[Ford tractor]

gross hp is what they charge you for and market the tractor with. Net hp is what you have available to do work with after you buy it.

Sadly, you are close but not all the way there.

Gross hp is how much the engine makes, typically with no alternator, intake filter or muffler. Just the engine, best case. Net hp is what the engine makes as it sits in the tractor. It's not useable as it has to go through a transmission/differential or hydraulic pump before it can be used. PTO hp is the amount you can use at the pto (obviously!). It's about 5-8hp less than the net and 7-10 less than the gross and is impacted by drive line losses. Drawbar hp is the amount of pulling work you can do. It's impacted by both driveline losses and geometry / traction. It may be a bit more or less than PTO hp depending on the machine. A heavier machine will have better traction and more drawbar hp than a lighter machine with the identical engine.

The real hp numbers you should compare are either drawbar or PTO hp depending on what you will be doing with the machine.

So the better statement is that Gross HP is what they charge you for, but PTO (or drawbar) hp is what you buy.