PTO rpm independent from engine rpm?

[Foozle]

Hi,

I have an L5740 and was wondering whether there was anyway to run the PTO at a higher rpm independent of revving up the engine. I seem to recall certain other tractors being able to do this. The application I have in mind is for my flail mower. When I'm cutting my lawn it doesn't require a lot of strength to cut it, so I'd like to use less fuel by reducing the engine RPM but keeping the PTO rpm high.

Anyone know if this is possible with the L grand series?

Thanks

 

[Bird]

According to the specifications listed on Kubota's website, it is not possible. The rear PTO is a single speed -540 RPM, while the optional mid-PTO is a single speed - 2000 RPM.

 

[Harvest Moon]

I don't know if this will help but the subject has come up before:

http://www.tractorbynet.com/forums/kubota-owning-operating/5244-power-take-off-speed-increaser.html

I'm sure I've seen a shaft mounted PTO speed changer but I'm not sure where. Here is one designed for a hydraulic pump, with the right adapters something like this may get the job done.

http://www.bareco.com.au/files/pto2002/pto100.htm

 

[rbargeron]

Harvest Moon's first link above is to a question I posted in 2001 - it later turned into this thread about converting my tractor's pto gearbox to have two speeds. The Australian version of my L5450 tractor has a 2-speed rear pto gearbox - so I bought the necessary pieces to add the higher speed myself. I recently acquired another L5450 and I've converted that one too.

But for the L5740 model Bird is right, the U.S. version is offered with 540 rear pto and 2000 mid-pto - both single speed setups. The Kubota Australia website also lists the L5740's rear pto as 540 rpm only. So unless there's another version for some other country that has 2 speeds, the shaft-mounted increaser may be the only answer. The Bareco increaser ratio of 1 : 3.75 is way more than needed. Something between 50% and 75% increase is what you're after.

 

[Foozle]

I appreciate the input. I figured there probably wasn't a way but thought I would inquire.

Thanks again to all who responded.

Dave

 

[rbargeron]

I'm assuming that you may not want a higher pto speed for either the tiller or the chipper - so maybe you could just increase the speed of the Caroni flail. Since it has belts in the drive, some pulley swapping would speed it up.

In this parts diagram pulleys 50 and 52 set the speed. They are keyed to their shafts. A good machinist could make new pulleys, one larger than 50 and one smaller than 52, for reasonable money. The tension idler 2 might still work as-is.

This may be a reasonably priced way to get what you're after. Might even be able to use the same belts. A bigger cover/guard would be needed for the top pulley, and you'd want to counsel anybody using it not to run the engine flat out at the new speed. Also keep the old parts in case you ever sell it.

As always, prompt cheerful refund if idea is bogus. Dick B

 

[oldgeezer]

Most implements I've seen which were designed to run at speeds higher that 540 had different spline patterns on the drive shaft. If you gear that thing up & hook some implement having the same spline pattern,to it that is designed to operate at 540 rpm, you're going to tear something up or hurt sombody. Some tractors have 2 rear shafts, one 540, one faster but shafts & splines are different on each one to keep someone from getting hurt or spending some big repair bucks. So BE CAREFUL.

 

[rbargeron]

I'm not proposing to run the flail any faster than it does now - with different pulleys the cutter head will still go the same speed as it did with a 540 pto input. The pto shaft will be able to turn at a lower rpm and still get the same cutting results.