hydraulic question

[trapper2]

Newbie here.

I bought a used sweepster broom to use on the front end loader of tractor. I never thought about the GPM and Pressure needs. My tractor puts out 9 GPM and 2400 PSI. The broom turns slow because of GPM, which I am ok with for what I am going to use it for. But the broom will stop if the bristles are in contact with the ground. My question is, isn't GPM determine the RPM's and Pressure determines Torque? Maybe the relief valve is faulty? Can I replace the Hydraulic motor with one that would work for my tractor? If so any ideas on what Motor I would need.

 

[Dave M7040]

Newbie here.

I bought a used sweepster broom to use on the front end loader of tractor. I never thought about the GPM and Pressure needs. My tractor puts out 9 GPM and 2400 PSI. The broom turns slow because of GPM, which I am ok with for what I am going to use it for. But the broom will stop if the bristles are in contact with the ground. My question is, isn't GPM determine the RPM's and Pressure determines Torque? Maybe the relief valve is faulty? Can I replace the Hydraulic motor with one that would work for my tractor? If so any ideas on what Motor I would need.

First describe how you have the hydraulics on the tractor connected to the sweeper. Does your tractor have a loader, power steering, does the 3 pt hitch work when you are running the sweeper.

Exactly what model of Sweepster? What was it connect to before you bought it. If a skidsteer, then it will have a motor requiring much higher gpm than you have. Sweepster has lower gpm motors for their sweepers.

Dave M7040

 

[trapper2]

I had the sweeper connected using rear remotes and ran hoses to the front to connect to sweeper. I also tried connecting it to the PB off the loader valve. No difference either way. Tractor does have power steering and I did not try the 3 point while the sweeper was rotating. The sweepster model is S32C6 and I believe it was connected to a john deere tractor not a skidsteer. I have called the company and found out that the motor is 18 cubic inch/Rev. My tractor is about 49 hp.

 

[Dave M7040]

I had the sweeper connected using rear remotes and ran hoses to the front to connect to sweeper. I also tried connecting it to the PB off the loader valve. No difference either way. Tractor does have power steering and I did not try the 3 point while the sweeper was rotating. The sweepster model is S32C6 and I believe it was connected to a john deere tractor not a skidsteer. I have called the company and found out that the motor is 18 cubic inch/Rev. My tractor is about 49 hp.

Some John Deere tractors were built using a "Closed Center," hydraulic system whereas yours is almost certainly an "Open Center," design.

Is there a hydraulic valve that come with the sweeper that you are using?

18 cubic inches per revolution..... what rpm should the sweeper rotate at?

If the motor you have is directly connected to the broom and is rotating at 100 rpm, it will consume 8 gpm

Do they have a smaller cubic inch motor for your sweeper?

Is the sweeper in the link below what yours looks like?

http://www.sweepsterbrooms.com/manuals/S26 S30 MRHL & CTC 51-4179.pdf


Dave M7040

 

[trapper2]

There is no valve that came with the sweeper, I was just using valve for rear remote to control it.
Sweeper should rotate around 160-200 rpm.
The sweeper is very similar to the one in your link. I think that is the newer model.
I guess that is my question...can I put a smaller cubic inch motor on it to match what my tractor hydraulics puts out?

 

[ericm979]

you can but the smaller motor at the same pressure will produce less power.

Your tractor has 8.7. gpm per tractordata. The motor you're trying to drive would take 12.5 gpm at 160 rpm. At 2100 psi and 12.5 gpm the standard motor makes 15.3 hp. At 8.7 gpm and 2100 psi it'd be 10 hp. You're probably not getting all of that 8.7 gpm out the remotes. If the speed of the broom is assumed to be fixed, torque is directly proportional to HP- 2/3 the HP means 2/3 the torque.

If you're willing to take less rpm at the broom you could use a motor that would turn a lower rpm at your gpm, which I think means a larger displacement (think of it like a cylinder: larger means more power but takes longer to fill). But I think right now you're coming up against friction in the broom and possibly in the motor as well. Or just being out of it's operating range.

 

[trapper2]

sounds like I am stuck with what I got. Thanks for the replies

 

[ericm979]

You could buy or make a hydraulic power pack with a pump driven off the PTO and it's own tank.

 

[Dave M7040]

sounds like I am stuck with what I got. Thanks for the replies

Since you got the info on the existing motor from I assume Sweepster, talk to them about a motor which they suggest will work with the hydraulic flow your tractor produces.

Their advertising says 8 gpm is the low end. If you were in the initial ordering process of buying a sweeper, they claim they will supply a motor to match your tractor.

They may also suggest replacing the broom with a smaller diameter one which would lower the torque needs of the sweeper.

Dave M7040

 

[grsthegreat]

yup. the only way around that is with a 3 point mounted hydraulic tank and pto pump. expensive for a broom. I have one for my front snow blower, and can adapt it to run front equipment like brooms and post hole diggers. Mine puts out 15 GPM at 3,000 psi. It mimics a skid steer performance.

 

[ptsg]

Wondering if it is a mechanical issue and not an hydraulic issue. Maybe there is a shear bolt or broken key in the motor shaft.

It should still have the power with your tractor, it would turn slower due to less GPM available. Have you used your remotes with another attachment? Is the relief valve for the remotes set at the right pressure?

 

[trapper2]

Those are valid points. I will look at mechanical issues to see if anything looks wrong.
I have used the remotes for top and tilt. I will have to figure out how to check the relief setting of the remotes. I'm an electrical guy not a hydraulic guy so I am still learning. Thanks

 

[Dave M7040]

Those are valid points. I will look at mechanical issues to see if anything looks wrong.
I have used the remotes for top and tilt. I will have to figure out how to check the relief setting of the remotes. I'm an electrical guy not a hydraulic guy so I am still learning. Thanks

.

Testing the pressure available at the remotes is simple.

Buy a pressure gauge and 1/2 a quick coupler fitting . Around $30.

Plug the test gauge into a rear remote. With tractor at max rpms, move rear remote lever to direct flow to your gauge. Read immediately and stop test.

Finished. In 5 seconds you have your answer. Do not continue test for any longer as you will overheat hydraulic system.

You could also connect the same gauge, using a Tee, into the supply line to the sweeper motor so you can see what is happening as you try and operate it.

Dave M7040