PTO from hydraulic motor

   / PTO from hydraulic motor #1  

BrisMatt

Member
Joined
Oct 30, 2010
Messages
45
Location
Australia
Tractor
JD 455
I have a JD with auxillery hydraulic ports but without a rear PTO. You can buy a rear PTO kit for this machine but they are no longer sold in Australia and are very expensive. I was thinking about using the machines aux hydraulic port and control valve to run a hydraulic motor that acts as a rear PTO. I have found a few motors at surplus centre that run about 500-600 rpm and provide the adequate torque for my purposes. A link to a motor I had in mind is here.

I was just wondering has anyone attempted this before?

And what coupler is required to fit the pump shaft to a PTO shaft.

Thanks
Matt
 
   / PTO from hydraulic motor #2  
What is the hyd pressure on your pump? Do you have enough hyd flow to run that motor efficiently?

* Dynamic Model Number JPPS-125 H4-K-P
* Displacement 7.7 cu.-in./rev.
* Pressure
1400 PSI Cont.
2000 PSI Int.
* Torque
1354 Cont. in.-lbs.
* Speed
512 RPM Cont.

* Flow
18 GPM Cont.

I believe Surplus Hyd also has the splined coupler
 
   / PTO from hydraulic motor #3  
5 GPM and 7.7 cu in, speed of hyd motor would be about 150 rpm
 
   / PTO from hydraulic motor
  • Thread Starter
#4  
Looks like I have mixed up my l/min with gpm.

The manual states the charge pump flow is 17.0 L/min (4.5gpm) observed
and the relief valve 1066 psi

its a JD 455. They operate FEL's from these ports usually.
 
   / PTO from hydraulic motor
  • Thread Starter
#5  
Are these numbers too low to have a rear PTO with an rpm close to 540rpm.
 
   / PTO from hydraulic motor #6  
Are these numbers too low to have a rear PTO with an rpm close to 540rpm.
No - but they are too low to have a rear PTO with any kind of power behind it at that speed.

4.5 GPM of flow run thru a motor with a displacement of 1.92 cu. in. yields 541 rpm

but .... a motor with a displacement of 1.92 cu. in. ..... running at a pressure of 1066 ..... only yields 326 in lbs of torque (which is a little over 27 foot lbs, or almost 37 newton-meters, of torque :()

A larger displacement motor will get you more torque (some) at the same pressure .... but that will result in a slower speed, given your flow (gpm)

I think you really need more flow and pressure to do any substantive work :eek:(as in a rear PTO)
 
   / PTO from hydraulic motor
  • Thread Starter
#7  
Yes that equates to about 3hp.

I do have a mid PTO which I dont require. It spins at 2000 rpm to run a mower deck. Perhaps a new pump hooked up to that to run a bigger motor. I see surplus centre has PTO motors that require about 20gpm.
 
   / PTO from hydraulic motor #8  
Yes that equates to about 3hp.
Yup :(

I do have a mid PTO which I dont require. It spins at 2000 rpm to run a mower deck. Perhaps a new pump hooked up to that to run a bigger motor.
I'm actually looking at doing that very thing myself - to drive a hydraulic pump to power a hydraulic motor to run a snowblower - see my thread here:

Convert Rear PTO Snowblower to Front Hydraulic

I see surplus centre has PTO motors that require about 20gpm.
It's not that they necessarily require it, it's that they are capable of using it ....

Think about it this way:

A particular flow (in GPM) thru a hydraulic motor (under no load) of a particular displacement will determine the speed of rotation.

When the motor (and as a consequence, the hydraulic pump) encounters resistance, pressure builds - which provides the force/torque/power to accomplish work.
 
   / PTO from hydraulic motor
  • Thread Starter
#9  
Where can I find a coupling to connect a hydraulic motor to the flywheel of my Yanmar Diesel engine out of my JD 455?
Thanks
Matt
 
 
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