3-Point Hitch PTO Output for wood chipper

   / PTO Output for wood chipper #1  

robstaples

Gold Member
Joined
Oct 13, 2013
Messages
355
Location
Near Ann Abor, Michigan
Tractor
kubota / L39 TLB, BX2680
I was wondering about the PTO power out rating on tractors. To use my tractor as an example, it's rated at 39 hp gross and 37.4 hp net with a max pto at 30.5 hp. It makes sense that the sum of the power users can't exceed the source. And I would expect some mechanical losses in the drive train and then there is power steering pump and hydraulic pump losses with just circulating fluid.
My question is: if the tractor is parked with a PTO chipper attached, what is the maximum hp to expect at the rear pto? This is more a theoretical question seeing I doubt I could tell the difference in performance between 30 and 35 ish hp. But it seems reasonable to expect more than 30hp.
Thoughts?
ps my chipper isn't here yet but has a recommended 35-65 hp.
 
   / PTO Output for wood chipper #2  
I would think that parked you would get the full 30.5, nothing more. While driving and running the PTO that dips into the 20's and if you are driving uphill and turning for example the PTO power could drop into the teens. Just a guess.

What chipper did you go with?
 
   / PTO Output for wood chipper
  • Thread Starter
#3  
My limited experience has been with a pto hydraulic pump powering a front snow blower. When I was going along in 8-10 inches , full width of blower into snow, the pump started to slow the engine down, so I slowed down and the engine speed returned. The pump was rated at greater than my max pto ( on my B3350).
So I conclude ( maybe wrong) that the PTO will take more than the engine has and slow it down and in my case self limiting the snow into the auger. Pure conjecture but seems reasonable.
I'm getting a bearcat pto as I have a BC self powered 4" with gravity feed and have been very happy with it except when I self load buckthorn tops.
 
   / PTO Output for wood chipper #4  
I was wondering about the PTO power out rating on tractors. To use my tractor as an example, it's rated at 39 hp gross and 37.4 hp net with a max pto at 30.5 hp. It makes sense that the sum of the power users can't exceed the source. And I would expect some mechanical losses in the drive train and then there is power steering pump and hydraulic pump losses with just circulating fluid.
My question is: if the tractor is parked with a PTO chipper attached, what is the maximum hp to expect at the rear pto? This is more a theoretical question seeing I doubt I could tell the difference in performance between 30 and 35 ish hp. But it seems reasonable to expect more than 30hp.
Thoughts?
ps my chipper isn't here yet but has a recommended 35-65 hp.

Check on the Nebraska trials rating for ending PTO and draw bar horse power. Compare similar specifications to your engine/tractor

30 HP is "light duty" chipping. I would go with 100 hp for commercial applications. half that for domestic uses. I get along with a largish garden chipper shredder and 30 HP at the PTO, but it bogs when fed big wood.
 
   / PTO Output for wood chipper #5  
Nice. I have a bearcat 5" chipper shredder with a blower and I run it with a Farmall Super M that has somewhere in the neighborhood of 40 HP. I have more HP than the machine can handle and occasionally burn up belts when the chipper slows down and the tractor doesn't.

I suspect your setup will work alright as long as the hydraulic feed will slow down to allow the tractor to get back up to RPM as it will likely bog down when you run bigger material. I would think on smaller material it will do fine. Let us know how it works.
 
 
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