Power Beyond - Operation Question

[Spudland_Dave]

With all this talk about power beyond it brought up a question I have...

Is it possible to utililize the PB while the tractor is in motion? I'm guessing on a PR equipped machine its no problem but how about a eHydro?

For the sake of arguement I'll use this example.....I install a valve bank with a few sections in it in the PB loop....couple go to cylinders and on one spool I have a small hydraulic motor which turns a small conveyor belt......all of which I would be using while the tractor is in motion. Is that a possibility?

 

[CinderSchnauzer]

I's say yes - at least on my JD 3320 eHydro - AFAIK the PB lines simply provide uncontrolled access to the basic hydraulic flow and then the tool(s) need their own control valves.

 

[beenthere]

The hyd. pump is pumping all the time when the engine is running. Standing still or when in motion, pump is running and Hyd's is working.
I'm thinking your question may have another side to it.

 

[Rob-D]

Generally the PB is used to run rear implements. Log splitters, back hoes, etc. You could for instance, run a shute diverter on a rear snow blower with it and in this case you could change the direction of the shute as the tractor is moving.
So the answer is yes, in fact, I have reached around while going forward to raise the bucket on my BH.
Rob

 

[kennyd]

The hyd. pump is pumping all the time when the engine is running. Standing still or when in motion, pump is running and Hyd's is working.
I'm thinking your question may have another side to it.

Right...Remember Dave that the hydrostatic transmission has it's own pump driven from the crankshaft on the engine. The power steering and implement pump is a separate system. The only thing "common" is the sump.

So the short answer to your question is Yes, absolutely.

 

[AKfish]

I have reservations about the actual "capabilities" of such a configuration.

I do not disagree that it would NOT work - I think that yes; you would have hyd flow and function.

However, I do not believe that you would have sufficient flow (while the tractor is moving to effectively power very much).

Much depends upon 1.) How fast the tractor is moving (hyd demand) 2.) The dimensions of the valve body and the total hyd demand.

Whenever, I attempt to do any "intensive work" with my 110 when moving at a significant speed i.e. heavy loader work or run the hoe circuits - the tractor will drop speed - markedly! I have to back off the direction pedal in order to maintain hyd function to either the loader or the hoe.

I can nearly stall the machine by pulling the stabilizers or dipper, etc. when the tractor is in motion. When a cylinder ends travel and it goes to bypass - the hyd motor - will drop speed dramatically.

So, I would question how much "actual work" might be functionally possible with a tractor that has half the gpm flow rate of a 110? I can readily envision the moment you pull the PB circuit open (with the tractor in motion) and the hyd motor going to bypass.

AKfish

 

[Rob-D]

I'm not sure Fish. I think there's a difference between the 110 and the compacts.
Also flow rate is not power. I learned that when I went to more flow rate with the same implements. Power = pressure and as long as the pressure is up the power is up, things just move slower at less flow rate.
On the compacts there is very little if any change in rpms. I've raised a full bucket while going down the road at a good clip.
Rob

 

[Spudland_Dave]

Right...Remember Dave that the hydrostatic transmission has it's own pump driven from the crankshaft on the engine. The power steering and implement pump is a separate system. The only thing "common" is the sump.

So the short answer to your question is Yes, absolutely.

Thats the piece I was not thinking about...I knew there were 2 "zones" in the hyd. system, but I didnt know where the line was drawn...so other then the excess HP requirements if I were to use both the tranny & PS/Implement side at 100% both.. I'm good to go.
Awesome...

I was thinking for some reason that ground speed & force would suffer if I were to utilize the PB to its full extent in a worst case senario..In the senario in my head, the "rolling force" is minimal and I could substitue the hydraulic motor for a monkey turning a crank if I could get a monkey cheaper then a hyd. motor...:laughing:

Power = pressure and as long as the pressure is up the power is up, things just move slower at less flow rate.

Rob is 100% correct...College was good to me :drink:, but I do remember my fluid power course...

Pressure = Force
Flow = Speed

 

[AKfish]

I'm not disagreeing or stating that there is a loss of pressure or power - not at all.

The loss would be sufficient flow and the speed at which any real work could be done by the circuit.

Therefore, the practicality of the theroetical hyd function that "inches along" is....

So, my question remains unanswered - in a real world application - what work would/could be accomplished...?

AKfish

 

[jenkinsph]

I'm not disagreeing or stating that there is a loss of pressure or power - not at all.

The loss would be sufficient flow and the speed at which any real work could be done by the circuit.

Therefore, the practicality of the theroetical hyd function that "inches along" is....

So, my question remains unanswered - in a real world application - what work would/could be accomplished...?

AKfish

AKfish,
The difference is the 110tlb has a much larger hydraulic system about 30 gpm at a maximum pressure of 3000 psi while having a relatively small engine at 43hp. So the hydraulic system is a major load on the 110. My 4520 with 60 hp has a 17 gpm pump running at a maximum pressure of 2500psi. This is what makes the difference in your case.

 

[jenkinsph]

I should point out that using the hydraulics with heavy loads while driving on grades is a good reason to have the higher horsepower tractor models. For example a 4720 will do a better job of maintaining its speed under travel with a high hydraulic load than a 4120 will.

 

[AKfish]

AKfish,
The difference is the 110tlb has a much larger hydraulic system about 30 gpm at a maximum pressure of 3000 psi while having a relatively small engine at 43hp. So the hydraulic system is a major load on the 110. My 4520 with 60 hp has a 17 gpm pump running at a maximum pressure of 2500psi. This is what makes the difference in your case.

Steve, I can appreciate the power requirement's necessary to drive a 24gpm system @ 3000psi versus a 17gpm system @ 2500psi.

Most definitely, a 43hp tractor is going to labor to maintain that flow level versus a 60hp machine having to maintain a lesser flow level.

However, the real basis for my pessimism with Dave's idea is pretty simple and it's based upon the "open system" sump of these machines.

Try this on your 110 -- lower the stabilizers, move the tractor forward @ 1,300-1,400rpm and retract both stabilizers. What happens?

Dave's tractor is a 3720... with approx. 8.6 gpm implement pump capacity @ 2500psi.

AKfish

 

[Spudland_Dave]

So, my question remains unanswered - in a real world application - what work would/could be accomplished...?

AKfish

I concur.....

About the only thing I can say is this real world example. The chute rotator hyd motor on my snowblower is of similar size & type I would need to run what I have envisioned...currently Its plumbed into the 3rd SCV and I can use the motor no problem while using the blower & tractor in motion... Now of course I only use it momentarily...so like you said..in the real world, what would sustained use do?
I also got 2 roads I can go with this project..
A) Mechanical drive...I hate to do this because I prefer to have the variable speed of hydaulic drive.
B) Self contained hydraulic system, PTO drive...

I'm in no rush to find out...with a family addition scheduled for delivery mid July, fab time will be virtually Zero i'm sure. This was more a theory of operation question, and It looks like I'm not the only one wondering!