pto

unclehan · Jul 17, 2005

I've read that the PTO in the US are either 540rpm or 1000 rpm. Does this mean the speed of the PTO is always either 540 or 1000, regardless of application or engine speed?

How does the PTO speed stays constant when the engine speed and ground speed can vary?

Thanks

Keith_B · Jul 17, 2005

( I've read that the PTO in the US are either 540rpm or 1000 rpm. Does this mean the speed of the PTO is always either 540 or 1000, regardless of application or engine speed?

How does the PTO speed stays constant when the engine speed and ground speed can vary?

Thanks )

The PTO speed will vary according to the engine RPMs. Normally on your tach there will be an indicator of how many RPMs you need to run at 540 or 1000.

Not all applications require running at the full 540 or 1000. Running a posthole digger is a low RPM application, running a rotary mower will run at a mid speed or higher and other applications (such as a hay baler) will require running the full 540.

Most category 1 attachments will require the 540.

fire72 · Jul 17, 2005

In general, tractors in the compact utility range (the main focus of this board) are Category 1 tractors with 540 PTO. The 1000 PTO tractors are generally the larger agricultural tractors. Some Category 2 tractors (the utility/smaller ag tractor range) will have a selectable 540/1000 PTO.

Note that this applies to rear PTO. Tractors with a mid PTO for a belly mower or other mid/front mount PTO implement have a much higher RPM on the mid PTO.

PTO speeds vary with engine RPM. Your tractor will have a mark on the tachometer that indicates what engine speed will yield 540 RPM on the PTO.

Some older tractors, and a few new ones, will also have a ground speed PTO in which the PTO shaft runs off the movement of the tractor wheels across the ground, rather than from the engine RPM. This is used for spreaders or other implements where it is desireable for the action of the implement to be proportional to the speed of the tractor across the ground.

unclehan · Jul 17, 2005

but is it always necessary to run exactly at the engine rpm so that the PTO is 540 for a job? or can 530 be okay too?

Are there any jobs where a very precise PTO speed is required?

TractorLegend · Jul 18, 2005

Only when you're working gov'ment contracts...lol /forums/images/graemlins/grin.gif

MicroPilot · Jul 18, 2005

The only application that "requires" a specific PTO RPM that I can think of is when running a PTO powered generator. You "tune" the PTO speed so that the genny is outputting at 60 hz. This is not necessarilly exactly 540 RPM, but will probably be close.

On most tractors the engine RPMs that are required for the PTO to run at 540 RPM is just past past the peak torque RPMs of the engine. This allows the engine to have some "reserve" torque if the the implement starts to bog down.

unclehan · Jul 18, 2005

(

Some older tractors, and a few new ones, will also have a ground speed PTO in which the PTO shaft runs off the movement of the tractor wheels across the ground, rather than from the engine RPM. This is used for spreaders or other implements where it is desireable for the action of the implement to be proportional to the speed of the tractor across the ground.

)

can you please list some implements where its desirable for the action of the implement to be proportional to the speed of the tractor? (and if any of them requires precise speed ratio between the ground speed and the pto speed)
Thanks

txdon · Jul 18, 2005

unclehan, I'll get kind of specific on the PTO question and explain how the KUBOTA GRAND L series tractors with HST operate.

First of all lets pretend we are going to mow and the recommended speed, which is very common, is 540 RPM. On these models only the 540 is offered for the rear PTO.

The engine speed to obtain the specific 540 rpm on the PTO shaft will vary between the models but it will be between 2440 and 2680 engine RPM.

Here is the neat part: there is a display on the dash that digitally tells you how fast your PTO is going so instead of trying to remember the the required engine RPM for your model you can just look at the dash.

Now your Engine speed will vary and consequently your PTO speed will vary also when you go up hill or run through a thick area of grass but you can let off of your HST pedal (like down shifting) to slow the speed of the tractor down without touching the throttle lever to maintain the 540 PTO rpm.

The 540 is the recommend speed of the PTO shaft to operate the mower at the blade speed it was designed for, it will still mow above or below the exact 540. When mowing my PTO speed varies up to 50 rpms depending on the height of the grass (sometimes as high as the tractor).

I hope this has helped. I don't have any attachment that require an exact PTO speed.

What part of the world are you located in?

Soundguy · Jul 19, 2005

( can you please list some implements where its desirable for the action of the implement to be proportional to the speed of the tractor? (and if any of them requires precise speed ratio between the ground speed and the pto speed)
Vertain types of drop seeders or planters can be ground pto driven. this way a measured amount of seed per distance traveled is applied.. etc.

soundguy

TaterBug · Jul 19, 2005

Okay so you guys are talking about American made tractors right. What about a yanmar 1600 with 3 speed pto? I've read to be carefull and not run US implements in 3rd gear because they are not designed to run at such high rpm's. Does anyone have experience with this that can be shared? Thanks