540 or 1000 pto

[cowski]

i have a 70 pto horsepower tractor.i am buying a new bush hog for it.it has both pto's.which way should i go 540 or 1000 ? thanks

 

[Happypappy50]

540 is the way to go ....stronger driveline and less wear & tear.

 

[Brad_Blazer]

A 1000RPM PTO transmits power at a lower torque than a 540. If you are getting a large bush hog that will use all of your tractor's available power 1000RPM should give better service. If you don't need to transmit so much power, a 540 RPM implement is more universal as in any tractor can run it.

 

[LD1]

If you plan on buying new and keeping the bushhog forever, then it is really a matter of personal preference.

But if you are shopping for a used hog, OR dont plan on keeping it forever, stick to 540 because they are ALOT more common. You'd have a hard time trying to find or even re-sell 1000rpm implements. But 540 ones are everywhere.

 

[Barry Bowen]

540's are for lower power applications, and 1000's are for higher power applications. Look at the larger tractors, over 150 HP, and you will find most only have the 1000 RPM.

At only 70 HP you do not warrant using the1000 just for power, and the size of the mower will matter. Most batwing type mowers are 1000 rpm do to power requirements, but single spindles and most twins are only 540.

It is stricktly a question of power requirements.

 

[LD1]

540's are for lower power applications, and 1000's are for higher power applications. Look at the larger tractors, over 150 HP, and you will find most only have the 1000 RPM.

At only 70 HP you do not warrant using the1000 just for power, and the size of the mower will matter. Most batwing type mowers are 1000 rpm do to power requirements, but single spindles and most twins are only 540.

It is stricktly a question of power requirements.

Could you please explain what you mean by "540's are for lower power"

I think you understand it, but the way you worded it makes one think that the 1000rpm pto will deliver more power to the implement, and that is not correct.:thumbsup:

On the same tractor, they can deliver exactally the SAME amount of HP, whatever your PTO rating is.

But since HP is a function of torque and RPM's, the torque is NOT the same. The 540 (since it is "geared" lower will dilever more torque than the 1000). But all of that is irrelevent because the implements have their own gearbos to achieve the RPM they want.

So for a rotary cutter, lets say the MFG wants 800RPM output ot the blades. It doesnt matter weather it is a 540 or 1000 PTO because they are going to adjust the gearbox accordingley to get that 800RPM out.

But the differences is where the gear reduction AKA torque multiplication takes place. On the 1000PTO, more of the gear reduction takes place at the gearbox, so not as much torque gets transmitted through the PTO shaft. On the 540, more gear reduction takes place BEFORE the PTO, so a 540 has to transmit almost twice as much torque as the 1000, that is why they are built so much bigger and heavier.

But to just say that 540's are for low power and 1000's are for high power is incorrect. But the 1000's have the ability to transmit equal power as a 540, but with a smaller and less cumbersome shaft

 

[LD1]

540 is the way to go ....stronger driveline and less wear & tear.

This is only half right.

Yes the drivelines are stronger, BECAUSE they have to carry about twice the torque. So they are sized accordingly.

The wear and tear is debatable. Again, the 540 has about twice the torque load, but the 1000 spins faster.

 

[Brad_Blazer]

I would say Barry is 100% correct. Another way to put it is that the same shaft can safely transmit more power at 1000RPM.

Here's an excerpt from a shaft specification:

"M6 shafts are generally used on large logging winches, medium wood chippers, mowers, snow blowers, and roto tillers. Transmittable horse power at 540 rpm is 62hp, @ 1000 rpm 98hp."
shafts for Pete chipper

 

[LD1]

I would say Barry is 100% correct. Another way to put it is that the same shaft can safely transmit more power at 1000RPM.

Here's an excerpt from a shaft specification:

"M6 shafts are generally used on large logging winches, medium wood chippers, mowers, snow blowers, and roto tillers. Transmittable horse power at 540 rpm is 62hp, @ 1000 rpm 98hp."
shafts for Pete chipper

That is correct. The SAME shaft can transmit more power @ 1000rpm because the torque is less. That is why they are sized accordingly.

The OP is asking about a 70HP tractor with dual PTO's. So The MOST his tractor can transmit is 70HP. All that means is that the 540PTO has to be built heavier to take the added torque. Thats all. The gearing on the implement will make it operate where it needs to. But the 540 gearbox will be geared different to get the same end result.

So basically, a 1000rpm PTO can be built smaller to transmit the same amount of power out of a tractor. So I suppose there comes a point when a 540PTO will be just TOO big, but 70HP certainly isnt the limit of a 540.

And the formula for torque is.....Torque= HPx5252 divided by RPM

So that shaft you listed, using the 62HP and 540rpm is good to ~600ft-lbs
Using the 98HP and 1000rpm puts it at a tad over 500ft-lbs.

If someone were to make a 1500rpm PTO, the HP rating could be even higher:thumbsup:

 

[Reg]

WOW !!!
Such a short thread and so much nonsense (-:

It does not matter !
The tractor has 2 speeds for matching to different implements.
SOME implements are available with input gearing to match different PTO speeds.
What speed the shaft turns at is irrelevant, as long as you don't buy a 540 implement and run it at 1,000 - though it is OK to run it on the 1,000 gear at reduced revs if you are not loading it to its full power capacity (engine revs at 54%, etc.).

With a rotary mower blade (tip) speed matters, that will be achieved with a different ratio in the right angle drive on the top of the mower.

There might be VERY SLIGHT additional power losses involved in using a 1,000 RPM shaft speed - and of course any entanglement accident would pull things in quicker, may even tear clothing off instead of pulling it in - (speculative).

Me ?
I would buy the 540 version;
a) It can be run on the 1,000 output shaft at reduced revs (54%) and I like to do that for tasks that are "light" relative to the capacity of the tractor and implement.
This is a bit like running a truck in a very high overdrive, FINE on flat land with the option to switch to regular drive when the grade increases.
b) Re-sale value / ease of re-selling ? I try to not think about it, i.e. my plan is to keep it for the rest of my life, but who knows ?
c) Parts on the 1,000 version may be special order - not that blowing up the gear box is likely.