Kioti may have a different way of doing things.
When stall guard kicks in on my tractor the hydro sounds different.
My NX6010
- Thread starter MinnesotaEric
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Kioti may have a different way of doing things.
When stall guard kicks in on my tractor the hydro sounds different.
OP
MinnesotaEric
Super Member
My tractor goes VVVVVVVVVvvvvvvvvrrrr stop.
<stick it in neutral, press the brake down, turn the key>
VVVVVVVVVVVVVVVVVV
:laughing:
ishiboo
Platinum Member
It's interesting how many different ideas on how hydraulic systems work there are.
Not true at all. Volume (GPM = flow) does not matter. The lifting capability of the ram, and the functionality of the relief are governed solely by the pressure. But the lower the flow, the slower it will be. To have the relief open, the set pressure of the relief has to be met... if it's capable of getting there, it's capable of moving the load.
This is one of the most basic concepts of physics.
A .05GPM source of 3000PSI will lift the same load with the same cylinder as a 30GPM source at 3000PSI. It will just take MUCH longer. This is pretty simple, and compares via the law of the conservation of energy of RPM vs torque, volts vs amps, etc.
A certain input RPM does not guarantee the pump will be able to build that pressure though, depending on the pump design... but for our purposes...
Pump GPM is proportionate to input RPM, it won't produce the rated flow at a lower RPM than designed. At X GPM and Y PSI, you can find a specific horsepower number required for the input to maintain that output.
A 1/2HP 12vdc hydraulic pump is capable of lifting the same thing as your tractor. It will just take much longer.
Physics come into play. A loader on your example 25hp tractor will flip the tractor over before it lifts 4000 lbs, so it is designed to lift what it can lift efficiently, and not for the maximum lift.
The HST is a variable displacement pump type, there is not a relief that regulates pressure like the pump for the loader/3 point/remotes/etc... at least not in the circuit with the motor/pump, and at least not before it consumes all available power. That's why it can stall the engine. Don't think of it as a simple open center hydraulic system like used for the loader, where you could direct 100% of the flow through a hydraulic motor, lock it up and have the pressure hit the relief and everything goes on as planned Think of it more as a closed center pump connected directly to a motor - the input to the pump is directly the output of the motor and vice versa. Lock up the motor and the pump will stop (unless something gives first!)
The working HP of the system does not mean it cannot produce a load on the engine greater than that and stall the engine. The HST can and will take up 100% of the power the engine puts out.
The control for a Kubota or Kioti HST is the same - the swash plates, whether that is done mechanically or electronically to accomplish the goal and features, it doesn't much matter.
EricTheOracle said:
Not true at all. Volume (GPM = flow) does not matter. The lifting capability of the ram, and the functionality of the relief are governed solely by the pressure. But the lower the flow, the slower it will be. To have the relief open, the set pressure of the relief has to be met... if it's capable of getting there, it's capable of moving the load.
This is one of the most basic concepts of physics.
A .05GPM source of 3000PSI will lift the same load with the same cylinder as a 30GPM source at 3000PSI. It will just take MUCH longer. This is pretty simple, and compares via the law of the conservation of energy of RPM vs torque, volts vs amps, etc.
A certain input RPM does not guarantee the pump will be able to build that pressure though, depending on the pump design... but for our purposes...
EricTheOracle said:
Pump GPM is proportionate to input RPM, it won't produce the rated flow at a lower RPM than designed. At X GPM and Y PSI, you can find a specific horsepower number required for the input to maintain that output.
A 1/2HP 12vdc hydraulic pump is capable of lifting the same thing as your tractor. It will just take much longer.
Physics come into play. A loader on your example 25hp tractor will flip the tractor over before it lifts 4000 lbs, so it is designed to lift what it can lift efficiently, and not for the maximum lift.
The HST is a variable displacement pump type, there is not a relief that regulates pressure like the pump for the loader/3 point/remotes/etc... at least not in the circuit with the motor/pump, and at least not before it consumes all available power. That's why it can stall the engine. Don't think of it as a simple open center hydraulic system like used for the loader, where you could direct 100% of the flow through a hydraulic motor, lock it up and have the pressure hit the relief and everything goes on as planned Think of it more as a closed center pump connected directly to a motor - the input to the pump is directly the output of the motor and vice versa. Lock up the motor and the pump will stop (unless something gives first!)
The working HP of the system does not mean it cannot produce a load on the engine greater than that and stall the engine. The HST can and will take up 100% of the power the engine puts out.
The control for a Kubota or Kioti HST is the same - the swash plates, whether that is done mechanically or electronically to accomplish the goal and features, it doesn't much matter.
ishiboo
Platinum Member
That's not simply the swash plates then. Your foot on the pedal directly (or indirectly if electronic) controls them, "opening" them would be equivalent to you letting off the pedal.
OP
MinnesotaEric
Super Member
Please be forgiving of me for not presenting things clearly. Fluid moving has lower pressure than static fluid. We know that our arms can slowly pump a 40 ton bottle jack. The issue then is higher horsepower allows more fluid to flow thereby allowing the operator to work faster.
I can certainly understand how you understood that I was speaking about relief on the HST side from my remark, "The basic take-away is that higher flowing fluid has lower pressure than slower moving pressure and so more work can be done before going to relief." Although I was not clear the relief I'm speaking about is on the hydro side, not on the HST side. The context here is the video I made and posted where the wheels are still spinning and the loader has sent the hydro system to relief.
Thank you for your remarks as they serve to clarify since I did not make myself clear.
OP
MinnesotaEric
Super Member
Eric, I made a quick video so you can see how a compact with 44hp works
I had to be careful about lifting the rear end off of the ground when I drove into the material in the video I made. And then, if I didn't throttle up and I left the throttle matching feature on (which I always do), the tractor would bog down or conk out when I drove into my pile of sphagnum top soil I scraped off of my clearing. As you can see, the material doesn't even want to fall out of my dump trailer, let alone allow itself to get scooped up.
My tractor also bogs down while pushing a blade unless I throttle it up too.
Maybe Kapper can share his thoughts on a comparison between his 66hp John Deere 4720 and his NX6010 since he uses both?
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OP
MinnesotaEric
Super Member
OP
MinnesotaEric
Super Member
I did an ad hoc 200 hour review of my NX6010.
