Hydraulic Motors

[tessiers]

I am looking for some information on hydraulic motors

My tractor supplys 9 gpm at 2050 psi

If I have a motor that uses 12 gpm at 2000 psi to produce 800 rpm's do I loose torque or rpm's because of the reduced gpm's.

I am trying to get a motor to run at 540 RPM's to run pto equipment. I can get a motor that runs at 550 RPM's but it requires 15 gpm. at 2200 psi

Any help would be appreciated.

 

[radman1]

I am no hydraulic expert, but if your psi remains the same, but you have less flow, the rpms will be less. If the relationship is linear (this is an assumption), then the decrease from 12 gpm to 9 gpm is a decrease of 25%. 800 rpm @ 12 gpm should yeild about 600 rpms @ 9 gpm. This is close enough to the ideal 540 rpm that most mowers utilize. You could also slow down the tractor a little (decreasing flow) to obtain the 540 rpm. The motor you have should work.

 

[Farmerford]

tessiers:

Radman is right.

But have you considered the horsepower you need at the implement?

You 9gpm/2050psi tractor is probably in the 35hp range, with a pto hp of around 30.

I have not done the exact calculations, and to some extent the result depends on motor design, hose sizes, etc., but 9gpm of flow at 2050 psi will produce roughly 8 to 10 hp at the motor shaft. If the implements required most of the 30 hp available when direct coupled to the pto, they may not work as well at the reduced power.

If the motor will work at substantial loads for extended periods of time, you may find that the hydraulic fluid temperature will rise above the recommended maximum for your tractor. A typical maximum temperature is in the 170 to 190 def F range. An additional fluid cooler and/or reservoir will solve that problem.

 

[tessiers]

What I would like to do is make a loader attachment for my 3 point snow blower with a hydraulic motor and short drive shaft, keeping the whole blower original 3 point hookup. I now plow the snow all to one side of my driveway and then blow it all at once which only moderately works the tractor. I would like to be able to blow each storm as it falls with 2 or three passes while looking forward. If the snow is too heavy I would be able to switch back to the rear mount.

 

[Eagleview]

Ever thought of mounting a 25hp twin cylinder engine to the snow blower ? It would be self powered and as the tractor would only need to be run at high idle would also be economical . It would have sufficient power , useable on both ends of the tractor and i think cheaper than buying a hydraulic motor , oil cooler and plumbing and i do'nt think your tractor has enough flow or pressure for the hydraulic idea to work .

 

[radman1]

If you use the hydraulic motor for the FEL mounted snowblower, you will probably not have enough power for blowing snow with your flow and psi. May work in the light stuff but probably not well for the wet, heavy stuff. If you already have the motor, it would be relatively easy to run hoses from the back and give it a try. I will probably try a similar method next year but my motor will handle 18-20 gpm at 3000 psi. Not as powerful as rear pto but will probably work for me with most snows.