converting a 3 point hitch Auger to Hydraulic pump motor

[daddygoose]

what would be the required rpm and torque for a hydraulic motor run by a 9 GPM 2100 psi system. it has a 12 inch bit on it. im figuring the torque is more important than speed on this piece of equipment.

 

[Tazza]

You will need a converter to work it out:
https://www.surpluscenter.com/techhelp/speedtorque.htm
Hopefully that will give you some ideas of what you will need.

 

[daddygoose]

You will need a converter to work it out:
https://www.surpluscenter.com/techhelp/speedtorque.htm
Hopefully that will give you some ideas of what you will need.

i found a PTO drive motor on Surplus Center with the spline drive i need. but my question is the flow rate is 17.1 GPM cont and 21.0 int. Pressure 2576 PSI cont and 3091 int. turning 800 to 990 RPM,s with a torque of 1682 in-lbs.cont. my machine only puts out 9 GPM with 2150 PSI. i dont want that type of RPM's but could use the torque. with my low flow rate would this motor still work on my machine to turn the auger. the auger has a gear reduction so that helps a little wiht torque i would think. this motor runs around $ 274.

 

[Tazza]

i found a PTO drive motor on Surplus Center with the spline drive i need. but my question is the flow rate is 17.1 GPM cont and 21.0 int. Pressure 2576 PSI cont and 3091 int. turning 800 to 990 RPM,s with a torque of 1682 in-lbs.cont. my machine only puts out 9 GPM with 2150 PSI. i dont want that type of RPM's but could use the torque. with my low flow rate would this motor still work on my machine to turn the auger. the auger has a gear reduction so that helps a little wiht torque i would think. this motor runs around $ 274.

It will still turn, but the speed will be almst half of what they state as your flow is 9gpm, so 400-450 rpm at a guess. The other thing is, your hydraulic pressure is lower, so it won't get as much torque as is stated.
With that said, to gain torque you need more displacement in the motor, this one has essentially twice the displacement of the motor that would ideally match your machine, so it will have more power.
Being an auger, you don't really need the speed, you just need the torque to pull through the ground. I believe the motor would do it, but it will not do it as fast. With your lower flow rate, you will have this limiting factor anyway.
You do know they also sell splined PTO adaptors right? you can get a motor with a standard keyed shaft and get an adaptor to suit, i have bought one off them in the past.

 

[skidsteer.ca]

It will still turn, but the speed will be almst half of what they state as your flow is 9gpm, so 400-450 rpm at a guess. The other thing is, your hydraulic pressure is lower, so it won't get as much torque as is stated.
With that said, to gain torque you need more displacement in the motor, this one has essentially twice the displacement of the motor that would ideally match your machine, so it will have more power.
Being an auger, you don't really need the speed, you just need the torque to pull through the ground. I believe the motor would do it, but it will not do it as fast. With your lower flow rate, you will have this limiting factor anyway.
You do know they also sell splined PTO adaptors right? you can get a motor with a standard keyed shaft and get an adaptor to suit, i have bought one off them in the past.

You need to calculate your gear reduction of the drive.
Say it put 2 turns in to put one turn of the bit then that is a 2 to 1 ratio. It is 1/2 your rpm and doubling the torque.
Once you have this you need to use a hydraulic calculator to figure what volume of motor will give you the torque you need with your pressure. After you figure that torque required and have picked out a motor with a corect displacement then you can figure the rpm 9gpm of flow will give you through that displacement of motor.
Hydraulic skidsteer augers typically have 1500 ft lbs or torque (not inch lbs because that is 1/12 as much) at 3000 psi and can turn up to a 30" dia bit.
Since you only have a bit over 2000 psi the output of that "factory built" auger would be 2000 ft lbs on your machine. So instead of a 30" bit your down to say 22 or 24"
Using this info you can decide on how much torque to shoot for based on the bit size you want to use, Then try to figure what motor volume will produce the torque you need based on your loader pressure. Then you can see what rpm your flow will spin that motor at and decide if that will be fast enough for you to live with.
We sell Premier Augers http://premieraugers.com and their 10PD model drive puts out 1274 ft lbs at 2500psi or 1529 ft lbs at 3000 psi and 60 rpm at 10 gpm of flow and is rated up to 24" bit.
Hopefully this project comes in well under $1000 because not too much more then that will buy you a 10PD
They also make a smaller 5pd as well for up to a 12" bit.
Hope that helps.
Ken