JD5310 hydraulic motor hook up help

[nathansv6]

Hi,
I would like to hook up a rotavator to the JD5310. How is it possible. How much pressure availble and what motor and valve should use. Thank you

 

[J_J]

Well, just how big is the rototiller. Did it have a motor on it before. How wide is it. Is this something you are wanting to convert?

I have a 72 in hyd rototiller , and that 4 cu in motor uses about 12 GPM at 2750 psi, and develops about 20 HP . I don't know the exact rpm, but it turns at about 650 RPM.

A 10 GPM tractor pump turning at 2500 rpm requires about .9 cu in pump displacement. To pump 10 GPM at 2500 engine rpm, will take about 17 HP

At 85 % efficiency, a hyd motor with 10 GPM going to it, it will develop 15 hp , and it will turn at 544 rpm. This may not be enough torque, so you can increase the cu in displacement to get more torque, and of course the hyd motor will turn slower.

What you have to do, is to back track and work from some unknowns, such as, how much HP will it take to turn this mass of steel at a certain rpm to till the ground. The above data is just a sample of what you can expect. Some things you might know are, if it was a PTO tiller, then the input would have been 540. Then you know how much HP the tractor will develop at 540. Assume the PTO HP will be about 3 to 5 HP lower than the engine HP.


https://www.surpluscenter.com/item.asp?UID=2009112905234749&item=9-4124-04&catname=hydraulic.

 

[nathansv6]

Hi J J.
Thanks for the reply. The rototiller width of 60 inchs with 18 inches dia requiring RPM about 300.
Is it possible to hook the motor in the romote outlet which supplies power to the trailer single acting cylinder? Would be there enough power to support the motor...I am completely new hydraulics... I appreciate for your understanding.
yes its a PTO tiller, want to change to hydraulics...

 

[J_J]

It will depend on how many GPM you pump will supply. You tractor hyd pump was designed to develop so much hyd power, which has to run say, power steering, hydrostatic transmission, FEL, etc. You can run it with just about any hyd motor, but the ideal hyd motor will be one that can give you the rpm and torque that you need to work the tiller. I would suggest looking at some hyd tillers, and note the size of the hyd motor, and the required HP/GPM necessary to run it.

As far as the remote outlet, if it can supply the GPM, then it can run the motor assuming the hoses are correct. If you have a tractor manual, it will tell you the potential of your tractor.

 

[nathansv6]

Thank you J J

 

[dfkrug]

Hi J J.
Thanks for the reply. The rototiller width of 60 inchs with 18 inches dia requiring RPM about 300.
Is it possible to hook the motor in the romote outlet which supplies power to the trailer single acting cylinder? Would be there enough power to support the motor...I am completely new hydraulics... I appreciate for your understanding.
yes its a PTO tiller, want to change to hydraulics...

That's a big tiller. What do you gain by going to hyd drive from PTO drive?

If you do use your remote valve, it needs to be one that can be used for
double-acting cylinders, and have a detented lever so it stays in the 'ON'
position. You don't really need a motor control valve here. If it is a valve
for a single-acting cyl, then that won't work. It MAY be a DA valve, but
the return work port is teed into the out port for using your SA cyl.

When choosing a motor, don't forget that the PTO input shaft speed is
geared down inside the tiller. You don't want to be guessing at
what motor displacement to buy.

I do not know that tractor...what pressure is available at the remotes?
2000psi motors (e.g. Charlynn S) are much cheaper than 2500psi units.

 

[J_J]

dfkrug,

Quote:

When choosing a motor, don't forget that the PTO input shaft speed is
geared down inside the tiller. You don't want to be guessing at
what motor displacement to buy.


You still have to know the designed HP requirement for the tiller using the PTO. Say the tiller needs 20 HP to run it . You then have to find a hyd motor that will develop the 20 HP. If the pump on the tractor can put out that potential HP, then it should be OK. The pump will take so much HP to run it at maximum, and the motor using that fluid will develop slightly less HP, due to loss of efficiency, of about 85 %.

 

[dfkrug]

You still have to know the designed HP requirement for the tiller using the PTO. Say the tiller needs 20 HP to run it . You then have to find a hyd motor that will develop the 20 HP. If the pump on the tractor can put out that potential HP, then it should be OK. The pump will take so much HP to run it at maximum, and the motor using that fluid will develop slightly less HP, due to loss of efficiency, of about 85 %.

I would simply buy a motor that makes full use of the tractor's hyd system's
available pressure, having the displacement that will turn his input shaft
at the correct speed range. If that pressure/flow can deliver more power
than used by the tiller, then no problem. If less power, the tractor may
not be able to operate it in some soil conditions and ground speeds. I
would go hyd only if the tractor has power to spare, since using the PTO
will deliver more power to the tiller.

Clearly if the motor that makes max use of the JD's hydraulics can only
put out less power than required to make max use of the tiller, the OP
has a problem.

 

[HL649]

You need to find how many HP the tiller requires to run. Since the tiller is an old PTO design; you know that the shaft speed is 540. You then have to determine how much flow (i.e., GPM) you need to make that HP at 540 RPM.

Then take a look at the hydraulics on your tractor and see if the GPM output is equal to or greater than the tiller requirements. If the tractor doesn't pump as much oil as is required to run the tiller you might as well stop right there and abandon your project. If your tractor does pump enouigh then go for it!

Hope that helps.

 

[radman1]

According to my calculations, the 5310 has 11.4 gpm according to tractor data.com. To get 540 rpm, need a motor with a displacement of 4.9 cubic inches. At 11.4 gpm, 2500 psi and 4.9 cu in displacement motor, will give a torque of 1950 in/lbs. This coverts to 16.7 hp assuming 85% efficiency of the motor which I feel is a little optimal and 65% efficiency may be more realistic. 16.7 hp is not much power for the tiller.

Also remember, the pto hp of a tractor diesel engine will actually increase as the engine rpm gets pulled down when working. This is why torque and hp curves for engines have a sort of bell shapped curve. This is why motors power through tough working conditions without stalling. The hydraulic motor has max hp at max hydraulic flow for a given constant psi. Converely, as a hydraulic motor undergoes increasing loads, the hp output will simply continue to drop due to the reduced hydraulic flow because of the relief valve in the hydraulic system.

My Toolcat 5610 has nearly 28 gpm for its hydraulic pto at 3000 psi. This is a lot more flow and pressure than the JD 5310 has. I have used a 6' tiller on the TC and the tiller can easily overpower the hydraulic pto and stop the tiller quickly. My CUT on the same tiller can easily power through similar conditions.