PTO Info Needed

[jtcweb]

OK, this computer geek is somewhat of a newbie when it comes to tractors. I have been lurking for some time but want to make sure I understand PTO's. Can someone confirm/correct my statements below?

"Live" PTO: The PTO can be turning without the wheels going arround. Needed for something like a 3 pt chipper/shreader.

540/1000: Two common RPM's for PTO's. Orginal (old standard?) was 540, now some tractors come with PTO's that can shift up to 1000 RPM as well.

Two Stage Clutch: Not sure but some people say it is nice when mowing.

 

[ICGREEN]

Live PTO is a direct connection from the engine to the PTO. Push the clutch, wheels moving or not it doesn't matter. The PTO runs until you shut it off. This is the preferable PTO dirive. 540 rpm is still the standard rear PTO speed. Most 3ph or rear attach implements are geared to run with the 540 rpm pto. A few tractors have 1000 rpm available on the rear PTO but I personally have never ran across an implement that ran on 1000 rpm. Most of the time the 1000 rpm is used on a mid PTO. Front mount snow blowers, mmm are usually geared for the 1000 rpm. The two stage clutch is only an issue if you do not have live PTO. The theory is that pushing the clutch part way stops the tractor and pushing the clutch all the way stops the tractor and PTO. I don't know how the new generation of tractors work but with the older farm tractors it worked ok if the PTO wasn't under a heavy load but if it was the tractor and the PTO came to a grinding halt even if the clutch was pushed only part way. If you're looking to get a tractor I highly recommend a live PTO.

 

[rf33]

1000 RPM PTO is the standard for larger tractors and implements. Most anything over 100HP has a 1000 RPM PTO. Larger mowers, balers, etc are often available in either speed.

 

[chim]

My B7500 has a selectable (540 / 960) PTO RPM. I sometimes use the side discharge RFM as a blower when the grass is growing faster than I get around to mowing it. I mow (too high) grass one day, then go back a day or so later and blow some out into the bordering fields/ fencerows. For areas too distant from the borders, it gets blown into a windrow for quick pickup and disposal.

Anyhow, when doing this, the tractor needs to go slow with the mower going fast. I borrowed a mechanical tach at work, and checked the PTO at various engine RPM's and HI/LO PTO gears. I discovered that with the PTO in the 960 position and the engine at 1500 RPM, the measured PTO RPM was 540. As long as the tractor is on flat land so it doesn't lug the engine, this is the combo I've been using. When I removed a tree Friday, this is how I got rid of the leaves and twigs instead of raking them up. I NEVER rake leaves in the Fall. This will be the third tractor that has helped me avoid that job.

Mowing grass is a different story, especially with hills. The tractor will bog down...............chim

 

[EdKing]

There are two styles of PTO, live and non live. Non live, the wheels need to be turning for the PTO to turn, mostly found on older tractors. There are 2 styles of live PTO, normal or manual and independant. Manual operates with the 2 stage clutch, push the clutch half way, the wheels stop, the PTO turns. Push the clutch all the way, the PTO stops as well. Independant turns whether the clucth is engaged or not.

 

[Slamfire]

So what would I call the one on my Mitsubishi that runs only when the clutch is engaged through a seperate 4 speed transmission?

 

[Inspector507]

Non-live

 

[Kelvin]

I've always called my Kubota B7100's PTO "non-live", but it will turn as long as the PTO gear lever is engaged and the clutch is not depressed. It doesn't matter whether the transmission is in gear or neutral, the PTO will spin.

Kelvin

 

[Kelvin]

jtcweb,

I hear a lot of different definitions for the various PTO types (live, continuous live, live independent, transmission driven, etc.).

Regardless of what name you apply to the PTO, I think that the main desired feature of the PTO is to be able to conveniently change from forward to reverse as well as change ground speed without stopping the PTO driven equipment (especially the mower). Hydrostatic transmissions offer great versatility with PTO operations; all of the variations on synchronized manual transmissions are acceptable as well. Non-synchronized manual transmissions can be a real hassle.

You will want the PTO to spin clockwise as you look at it from the rear.

Unless you look at a really old tractor (or possibly a grey tractor [another definition that you need to know]), you probably won't have to worry about the PTO not spinning on a stationairy tractor nor will you have to worry about the lack of an overrunning clutch on the PTO.

Kelvin

 

[GlennT]

If at all possible, you want a live PTO. You can get by without one, but it's a pain at times. I don't have a live PTO in my JD 670. When I shred my pasture or mow my yard, the shredder or mower operates only when the PTO lever is moved to the on position and THE CLUTCH IS ENGAGED (clutch pedal out). That means that the shredder or mower will only operate in two situations: (1) the tractor is in gear, the clutch pedal is out and the tractor is moving, or (2) the tractor is in neutral and the clutch pedal is out. Situation (2) is how I use my chipper. Again, you really do want a live PTO. If I have to stop when shredding or mowing, I usually back up several feet before starting again. If I don't do this there is a patch of unmowed grass where the shredder or mower was picking up speed and wasn't turning fast enough to cut the grass. You would certainly have to do this in heavy grass or the implement would plug up before the blade(s) were turning fast enough to cut and expel the clippings. Without a live PTO you can't stop and run the shredder or mower for a bit to allow it to purge itself if you run into an extra thick or high patch of grass and the implement starts to plug up.