JD 3720 Hydraulics

[Chris P]

I have a JD3720, awesome little tractor, does what it says on the box, but now I want to do a bit more....
I want to upgrade the hydraulics so that I can fit a trencher onto it, does anyone out there know if this is possible? Or is it going to have to be a PTO drive HPU unit?

 

[J_J]

You have this, so if you build or purchase one, it should work.

Hydraulics:
Type: open center
Capacity: 6.8 gal [25.7 L]
Valves: 5
Pump flow: 8.6 gpm [32.6 lpm]
Total flow: 13.9 gpm [52.6 lpm]


You could also install a PTO pump and run the trencher.

A hyd motor will run on just about any flow. The GPM's will determine the trencher rpm.

Hyd pressure determines the force applied.

 

[buickanddeere]

Tractor hydraulics should run up to a 10HP hydraulic motor.

 

[Chris P]

You have this, so if you build or purchase one, it should work.

Hydraulics:
Type: open center
Capacity: 6.8 gal [25.7 L]
Valves: 5
Pump flow: 8.6 gpm [32.6 lpm]
Total flow: 13.9 gpm [52.6 lpm]


You could also install a PTO pump and run the trencher.

A hyd motor will run on just about any flow. The GPM's will determine the trencher rpm.

Hyd pressure determines the force applied.

Thanks JJ
I am being a bit lazy here for a change and have found a trencher at a reasonable price, but with everything comes compromise.
So the trencher that I found requires between 45 and 80lpm @ between 180 to 240bar, the JD supplies as you have pointed out 32,6lpm @176bar. I had a look at the drawings and see that this is supplied by a geared pump that is what i was trying to find out if it was possible to upgrade. But found out this afternoon, for this flow, I would require a tank of aproximately 200l, so that I don't cook the oil.
So the notion of replacing the pump has gone out the window. So now I will see if I can find a PTO pump that will run the trencher, while still staying within my budget, or I must see if I can replace the motor on the trencher so that it is within the supply spec. but at the same time not compromise the trencher.....

 

[J_J]

200L is 54 gal

I am not so sure you need that kind of volume as most mobile tanks are about 1 to 1.5 of flow to volume, so as to save space and weight.

My machine is all hydraulic with three pumps and 4 wheel motors. My PTO drives hyd motors.

My tank is 20 gal and there is a hyd radiator with a fan.

My engine has the capacity for a 22 GPM pump at 3000 psi.

However, I don't usually use each pumps full potential at the same time, so the load is even less.