PTO Wood Chipper Hp ratings

[David_]

Hi all,

Might be a silly question but looking at PTO powered wood chippers and the ones I'm looking at all seem to be rated at ~30Hp. If I put bigger Hp tractors on will it just damage the machine/constantly break shearbolts? Most of my tractors are ~100Hp, I do have a MF 165 at ~60Hp but less keen on using that if I can avoid it! I've been advised by a friend my tractors are too big for the chippers I'm looking at, but my thinking is if it takes 30Hp to chip a 6" log then the machine will only ever load the tractor to 30Hp (as long as you don't put anything bigger than 6" into it!). Thoughts?

Cheers,
Dave

 

[Dave W]

A sub 30hp rated chipper won’t like being on 100hp very long. It should have a slip clutch rather than shear bolt so if it’s overloaded shouldn’t do it harm in theory.
Also a 30hp chipper in all honestly is going to be painful to use. It will struggle to take 2” of timber

 

[pycoed]

100hp tractor will be rated at 2500 odd revs. Surely if you run it at say 1300 revs it'll be down to 40ish hp. If you have a multi speed PTO just find one that'll give 540 rpm at the reduced engine revs.
e.g. I have a Japa circular saw that only needs 20hp to run. My mighty Zetor is 70hp, but if I run the PTO at the "1000" setting not 540 & set the engine to 1300 all seems OK.
(Which has just reminded me that I need to change the belts which I chewed up behind a 20hp Kubota engined Truckster!)

re 30hp chipper capacity:- My Titan chipper powered by a 13hp petrol engine has chipped a LOT of 3" branches over the last 12 years

 

[Foxcover]

100hp tractor will be rated at 2500 odd revs. Surely if you run it at say 1300 revs it'll be down to 40ish hp. If you have a multi speed PTO just find one that'll give 540 rpm at the reduced engine revs.
e.g. I have a Japa circular saw that only needs 20hp to run. My mighty Zetor is 70hp, but if I run the PTO at the "1000" setting not 540 & set the engine to 1300 all seems OK.
(Which has just reminded me that I need to change the belts which I chewed up behind a 20hp Kubota engined Truckster!)

re 30hp chipper capacity:- My Titan chipper powered by a 13hp petrol engine has chipped a LOT of 3" branches over the last 12 years

It will be the torque that will wreck the chipper, at 1300rpm a tractor will produce more torque than at 2500.

 

[suffolksmallholder]

If I was looking for a tractor powered chipper I would be looking at 8” minimum. That will need that 100 HP and then you can chip properly.
SS