Hydraulic vs PTO Horsepower?

[QwikDraw]

Is hydraulic HP on a skid steer equal to PTO HP on a tractor?

I guess the real queston is can a 85 HP tractor with a mulch head out preform an ASV RC 100 @ 67 hyd HP?

 

[radman1]

If the 85 hp is pto hp, then yes the tractor will outperform the ASV hydraulic hp of 65. There is a lot in inefficiency with a hydraulic pump although the ASV has 100 engine hp.

If the 85 hp is engine hp, then expect about 15-20 hp loss (closer to 15hp loss) by the time it reaches the pto. The two would then be closer. The tractor pto can run sustained hp at pto speed. Is the hydraulic motor of 65 hp constant or transient on the ASV? One other factor, a tractor pto is measure at pto speed. However, the maximum pto hp will increase as the rpms decrease. Most mid sized tractor pto speeds are around 2000-2200 rpm. However, the max pto hp will generally be around 1800-1900 rpm, thus the pto hp actually increases for some decrease in the rpm.I didn't realize this until I looked at the NEBR. test lab results for tractors. It is a common finding with every tractor due to higher torque and engine hp at these rpms.

 

[Robbie Hegwood]

If you were starting and the engine on both. You have about 20% lose in h.p. when comverting to hyd. On a pto you will have lose thru the drive line and transmission also, but I don't know how much. My personally opinion it's easier to relieve hyd pressure than it is to relieve stress in the clutch arrangement on a pto driven unit.
But on the other hand I have run a pto driven tractor and mulcher and it wasn't bad. It was significantly more expensive per h.p..

 

[duane]

An important factor is torque. A hydraulic motor develops more torque as the RPMs decrease, to a maximum torque at 1 RPM. The following was taken out of a hydraulic motor catalog:


10 HP electric=15 HP hydraulic=19 HP diesel liquid cooled=22 HP liquid cooled gas=25 HP gas air cooled


FWIW