Implements and Horsepower ratings

[Porkie]

I have a New Holland TC40D tractor that I believe puts about 35 HP into the PTO and it powers a 72" Squealer Bush hog, an 84" finish mower and a 72" rototiller, all successfully.

I will probably replace it soon with a 55 to 75 HP geared tractor and I need to know if the additional HP and torque will work okay or will it ruin the implements?

If the pto is engaged slowly and the speed is at 540 rpm then shouldn't the stuff work fine?

I know that the mfg's show the HP requirements for their stuff but is that minimum or maximum?

Thanks for your answers!

Sam

 

[yooper1]

Hello there.

I do not have a definite answer for you only this...

I have seen some MFG'rs rate their implements at max (allowed?) PTO HP and some rate the min PTO HP.

Then some have a range of acceptable PTO HP's

not confusing at all :mur:

Someone should know a bit more

 

[TripleR]

While it is "best" to use the proper rated equipment, we have exceeded the HP recommendations on a finish mower and bush hog. If you are careful the worse you will probably do is burn your slip clutches or belts out quicker.

A real concern will be bending something due to the added weight of the tractor if you catch it on something.

 

[RoyJackson]

With an implement such as a finishing mower or rotary cutter, the gearboxes are rated at the maximum recommended PTO HP.
Chippers (in my limited experience) are rated by a minimum and maximum PTO HP.

As TripleR implied, use care and you should be OK...but when using a tractor with HP and weight greatly exceeding an earlier machine, it's going to be hard to use that care...
So, a matter of discipline (and common sense) on your part, or trade up to larger implements.

I'm not sure why you think you'd need more then 35 HP, but I'd suggest you stay closer to 55 PTO HP unless you want to upgrade those implements.

 

[twarr1]

This is an interesting thread. I would think that if the implement has a shear pin or slip clutch, then the only thing to really worry about with higher HP would be the driveline ahead of the shear pin/slip clutch.
Ground engaging equipment is a different matter of course.

 

[tractorworks]

"Ground engaging equipment is a different matter of course."
Sometomes mowers and brush cutters engage the ground, trees and buildings more than we would like.

 

[Ford tractor]

I have a New Holland TC40D tractor that I believe puts about 35 HP into the PTO and it powers a 72" Squealer Bush hog, an 84" finish mower and a 72" rototiller, all successfully.

I will probably replace it soon with a 55 to 75 HP geared tractor and I need to know if the additional HP and torque will work okay or will it ruin the implements?

If the pto is engaged slowly and the speed is at 540 rpm then shouldn't the stuff work fine?

I know that the mfg's show the HP requirements for their stuff but is that minimum or maximum?

Thanks for your answers!

Sam

The equipment typically has 2 ratings. A minimum to get it to work "satisfactorily" and a maximum that might damage it. Rotary cutters have the rule of thumb of 5hp per cutting ft. That is often based more on the weight of the implement related to the weight of the tractor than the power to run it. Depending on the cutter and the stuff being cut, it may require 3-7hp to operate satisfactorily. The gear boxes are often rated at 40, 60, 80, etc hp. That is the amount of power they can continuously transmit at 540 PTO rpm. The real limit is the amount of torque they can transfer before something twists off in 2 pieces, but HP is listed for convenience. For the stuff you list, the drive train protection needs to be up to snuff. If you have slip clutch on them, be sure to loosen them and actually slip the clutch every 2-4 weeks. 4 weeks if it has been dry, 2 weeks if it has been humid or Before every use if stored outside. Slip clutches are really only meant for those that will maintain them as they WILL rust up solid and allow damaging torque to be transmitted. Even your current machine is at risk if a slip clutch rusts up solid.

Even if you up to a 75 hp tractor you will be fine as long as your maintenance, technique for engaging and operating is sound. (Unless you bought the very bottom level equipment with 40hp gear boxes. They are typically junk and often damaged even when operated with under rated hp) Always engage the PTO at an idle and feather in the clutch to start massive things like a heavy stump jumper. Then slowly increase rpm to 540 PTO before beginning. Always operate at full 540 rpm. Oddly enough, there is MORE stress at lower rpms. HP ratings will often be much higher at greater operating rpms.