different fluid effect on hydraulic motor

[J_J]

bdog ,

How about a video of the auger in operation?

Are you putting a lot of down pressure on the auger?

 

[bdog]

Sorry I have not got back to this thread. I have been busy and have not done any more testing until now. I bought some more pressure gauges and did some tests.

I also removed the motor, sent it to the factory to have it tested and they said it was good as new.

I did try brand new augers and bits and it helped some but not a lot.

Hoses are 3/4" and I was wrong on my GPM. It is 19 not 24. I was looking at the wrong specs.

I am reading the pressures on T's installed in the lines that run between the spool valve that controls the auger motor and the motor.

For whatever reason I have 600 psi on both sides - the pressure and return when the skid steer is on but I am not operating any levers.

When drilling and not having a huge load it is about 2000 psi on the pressure side and 3-400 psi on the return. When the auger stalls I have 3300 psi on the pressure side and 2-300 psi on the return side.

As far as down pressure I use whatever is appropriate for the conditions. Sometimes more sometimes less. When I get in areas where the auger does not want to turn it will stall with very little down pressure.

 

[J_J]

Here is something you might try.

Run the return hose directly to tank, because any back pressure affects the overall pressure.

If the motor is developing 3000 psi, that says the pump is good and the motor is operating normally.

If the pump is putting out 19 GPM at 3000 psi, that is about 39 HP out to the motor, and given the efficiency of the hyd motor, @85 %, that would have the motor developing about 33.15 HP.

If the auger is stalling, either the ground is very hard, or the auger teeth need replacing, or the auger is to big for the hyd motor.

I have this hyd auger setup for my Power-Trac, and it also stalls if driven hard.

You should not have any pressure on the eauger motor with the spools in neutral.

Try this, remove the hoses from the motor, and hang them vertical, and with the auger control in neutral, no fluid should come out of the hoses, and if it does, the spools are leaking.

Did you have the hyd gages in series in a tee going to the hyd motor?

Your motor is supposed to develop 870 ft lbs, or 1180 Nm.

 

[bdog]

Thanks for the reply. I am not sure where exactly I could connect the return hose at tank. I was looking at it a bit today because I bought an auxillary cooler and I was going to install it on the return line from the auger before the quick connect but with 600 psi there at times this is a no go so I need to attach it to the tank as well. These dang skid steers are so compact and other than the quick connects on the front all the hydraulic stuff is pretty buried.

It is just dirt not hard ground. Auger is pretty much new as is the bit. Auger is 3.25" in diameter and bit is 3.5". My auger is about the size of the center shaft of the one you have pictured.

My motor has three hyrdaulic hoses going to it. two larger ones for the pressure and return and then one small one that is a case drain. It runs from the motor and t's into the return line coming from the valve block going to the quick connect on the skid steer. I am not exactly sure what this is for but it came that way from the manufacturer.

The auger functions like it should in that it never rotates unless you move the control lever and it seems to work smoothly in forward and reverse it just does not develop the power I think it should. I will do the leak test you mentioned tomorrow.

The T's with gauges were installed directly on the back of the spool valve and the the hoses were connected to the t's and running up to the motor.

 

[aczlan]

This is from your highflow ports? They should not (AFAIK) have anything coming out of the pressure/return ports when the valve is closed. Case drain, maybe depending on what else is hooked up, but probbaly not.
Is there a way to put a gauge on your "Pressure" port to see what the pressure goes to when the valve is closed?
If you have a couple of quick couplers and a pressure rated Tee, I might put it so that you can put it inline on the pressure of return side...
Is there a way for you to try the auger on another skidsteer? Sounds like you many need a new valve.

Aaron Z

 

[bdog]

This skid steer does not have highflow, Just regular. It is a JD 322. It definitely has flow to the aux quick connects even if I don't activate the lever that turns them on. I found this out by mistake by having the skid steer idling with aux hydraulics off and plugging a quick coupler into the skid steer with no hose attached and getting covered in oil. It must be a small amount of pressure or equal on both sides or something with out the lever engaged because I can't operate the auger without engaging the lever but it will definitely pump oil out of them.

I have not put a a gauge directly on the pressure side coming off the skid steer but I put one on the return side and get 600 psi there with the skid steer hydraulic lever off.

I will have another skid steer here to try this weekend but have not yet tried the auger on another one.

 

[aczlan]

I would try the open quick connect on the other skidsteer. I know that on our tractors, there is NO flow unless the valve is activated and no pressure (other than residual pressure).

Aaron Z

 

[bdog]

Try this, remove the hoses from the motor, and hang them vertical, and with the auger control in neutral, no fluid should come out of the hoses, and if it does, the spools are leaking.

I tried this and it does leak out. I did however talk to the manufacturer today and he said it is supposed to. The spool valve for the motor he said does not stop the flow when you put it in the neutral position rather it allows the pressure to equalize on both ports of the motor so that it doesn't suddenly stop when you let off of it. He said if it shut off the flow it would be like driving your car down the road and throwing it in park.

I will add that it is not like this auger does not work at all. I have drilled a lot of holes with it but it just does not have the power I think it should.

Still have not really figured anything out yet but I am going to have a different skid steer here tomorrow to try it out on. If it performs the same on the other skid steer I am going to look at upgrading to a bigger motor. Mine is the 400 CC and they offer a 500 and 630cc that will fit. I know this will slow down the rotation but the 630 will have about 50% more torque than my 400.

This leads to another question I have. I have been thinking all along that torque is what I need or the metric I should be looking at but you calculated the horsepower. From what I understand the torque on a hydraulic motor is determined by the PSI and volume of the pump and GPM does not have anything to do with it but the GPM does factor into the HP calculation.

For purposes of being able to spin this auger / prevent it from stalling while digging would increased GPM help since that increases HP or would it not since the torque is the same?

Reason I ask this is the skid steer that will be here tomorrow has more GPM but the same PSI.

 

[J_J]

The torque is dictated by cu in of the motor and pressure.

The speed of the auger is determined by the GPM and cu in displacement of the hyd motor.

Using the higher GPM skidsteer, will make the auger turn faster.

 

[aczlan]

I tried this and it does leak out. I did however talk to the manufacturer today and he said it is supposed to. The spool valve for the motor he said does not stop the flow when you put it in the neutral position rather it allows the pressure to equalize on both ports of the motor so that it doesn't suddenly stop when you let off of it. He said if it shut off the flow it would be like driving your car down the road and throwing it in park.

True, but that should stop or just drip after a few seconds rather than continuing to spray out. If it continues to spray out with the valve off, the valve has issues.

Aaron Z