Old Toro Reelmaster Project
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RJA.Ilex
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JJ.
I don't kow if your figures are correct but you are making the assumption that all pumps will be delivering max pressure at the same time. The cutter pumps will probably only run at max pressure on start up or stalling. The drive pump will depend on the gradient/terrain being climbed and the steering demand depends on the system used.
Robert128
The ransomes AR3 (triple rotary) uses a single 9.6 gpm pump working at upto 3626psi. Depending on the blade being used half of this may be used just to turn the blades at speed with no grass being cut. I think the max working pressure has been increased to increase the power available it used to be 3000psi on this circuit. This machine will strugle to cut long wet grass in the UK (mainly due to the volume of clippings created) but is remarkably capable
I don't kow if your figures are correct but you are making the assumption that all pumps will be delivering max pressure at the same time. The cutter pumps will probably only run at max pressure on start up or stalling. The drive pump will depend on the gradient/terrain being climbed and the steering demand depends on the system used.
Robert128
The ransomes AR3 (triple rotary) uses a single 9.6 gpm pump working at upto 3626psi. Depending on the blade being used half of this may be used just to turn the blades at speed with no grass being cut. I think the max working pressure has been increased to increase the power available it used to be 3000psi on this circuit. This machine will strugle to cut long wet grass in the UK (mainly due to the volume of clippings created) but is remarkably capable
J_J
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Yes, the pressure will change based on the resistance to the motors. and since you have three in series, or two, the pressure will vary. A pressure gage on the motors will tell the story better than we can only surmise. The cutting edge will also make a difference. He said the one motor stalled even with 3000 psi going to it, and those motors are not designed for that pressure. The pressure and the GPM will determine the torque available.
He will have to do some test, but I would not overpressure those motors . Actually, I think those DPRV will send everything above 1500 psi back to tank. That is all wasted energy.
He will have to do some test, but I would not overpressure those motors . Actually, I think those DPRV will send everything above 1500 psi back to tank. That is all wasted energy.
I ran a hydraulic line and combined the flow from both pumps. I could tell the difference right off the bat. Even with the machine idling, it could cut medium length grass. - I tested it at 3/4 throttle in high grass. It cut it but it got to the point where the blade started to slow down in the higher stuff. - If I can get all three turning like that I think I will be in good shape.
One question = All the plumbing is 1/2"/ Does the ransomes AR3 that you mentioned have 1/2 inch plumbing. - You said it uses a 9.6 gpm pump. Do you happen to know the Motor sizes. (GPM, RMP, Etc)
Thanks a bunch
One question = All the plumbing is 1/2"/ Does the ransomes AR3 that you mentioned have 1/2 inch plumbing. - You said it uses a 9.6 gpm pump. Do you happen to know the Motor sizes. (GPM, RMP, Etc)
Thanks a bunch
J_J
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How many motors did you power using the combined fluid from two pumps. Each pump can develop up to 3000 psi.
Something still doesn't make sense, because each motor has a 1500 psi relief valve on it.
By putting 14 GPM on a single motor, or was the two pumps powering 1,2,or 3 motors. How did you combine the two pumps.
I would think that a larger displacement hyd motor would use the pressure, and GPM, to develop more torque.
How many motors are you planning to use. If those other motors are still in the circuit, they are not offering much resistance, since there is not a blade on the other motors. They are just passing fluid in a free wheeling mode. Is the motor on the deck the first motor in the circuit, or the last.
Something still doesn't make sense, because each motor has a 1500 psi relief valve on it.
By putting 14 GPM on a single motor, or was the two pumps powering 1,2,or 3 motors. How did you combine the two pumps.
I would think that a larger displacement hyd motor would use the pressure, and GPM, to develop more torque.
How many motors are you planning to use. If those other motors are still in the circuit, they are not offering much resistance, since there is not a blade on the other motors. They are just passing fluid in a free wheeling mode. Is the motor on the deck the first motor in the circuit, or the last.
RJA.Ilex
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I can't remember the size of the hydrualic pipes on the AR3 but if you want more info then the tech manuals are available to download from their web site.Jacobsen and Ransomes Jacobsen - Renowned for Turf Maintenance Solutions
The tech manual gives pump and motor sizes and I think the hydraulic diagrams. The correct pipe size would be 5/8th from the link below based on 14 gpm at recommened velocityhttp://kuriyama.thomasnet.com/Asset/H%20SizingNomogram.pdf
1/2 inch will work but you will sacrifice some power.
The tech manual gives pump and motor sizes and I think the hydraulic diagrams. The correct pipe size would be 5/8th from the link below based on 14 gpm at recommened velocityhttp://kuriyama.thomasnet.com/Asset/H%20SizingNomogram.pdf
1/2 inch will work but you will sacrifice some power.
Tested it some more yesterday. It cuts good and about 1/3 power (blade tip speed apprears to be good. The only problem I have now is that when it gets into higher grass, the blade eventually stalls. So when it stalls, this is the relief valve opening up. When I run the machine at full throttle, it does not stall as quickly. With a relief valve set at 1500psi, why would it make a difference at how fast the motor is running?
Here is what I am wondering:
1. What exactly does the pilot line do (The third smaller line into each motor)
2. Does it act as a relief valve. What if I put a plug in each one?
3. I am having trouble finding these R3 relief valves. Is there one on the selonoid block or one for each motor. - Could they be inside the motor.
The engine is not working at all when those cutters are going. I am thinking if I can get the psi up higher, there will be more torque, (Will not stall the blades as quickly) Am i thinking right on this?
Here is what I am wondering:
1. What exactly does the pilot line do (The third smaller line into each motor)
2. Does it act as a relief valve. What if I put a plug in each one?
3. I am having trouble finding these R3 relief valves. Is there one on the selonoid block or one for each motor. - Could they be inside the motor.
The engine is not working at all when those cutters are going. I am thinking if I can get the psi up higher, there will be more torque, (Will not stall the blades as quickly) Am i thinking right on this?
J_J
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No, you are not thinking right. That third line is a case drain, and if you will look at the schematic, you will see this. The fluid going through the motor, also lubricates and helps to cool the motor somewhat. If you plug it I think you will destroy the motor. You say it stalls at slow speed, but how many GPM do you think you are giving the motor?
The GPM's that your machine is pumping, is dependent on engine rpm. If you run is low rpm, you may not be giving the motor enough fluid to develop the torque. If you go to the Surplus Hydraulics website, then go to tech help, and select the pump and HP calculator, and then go back and select motor speed and torque.
As designed, the 3000 psi capability is developed by the load. Before when the 7 GPM pump was pumping 7 GPM through the three motors, and each motor could develop up to a 1500 psi load on the pump. Those 1500 psi relief valves is designed to protect the motor, so any time you force the blades to work hard, the blade and motor is putting a load on the pump, and if the pressure builds up to 1500, and if you continue to work it harder than designed, the relief will go off, dumping pressure and fluid until the pressure is below 1500. You are defeating the purpose of your mower is you try and force it to do more. If you put a gage on the motor or relief valve, you can see about when you are using the motor at full potential.
One of those hyd pumps will operate up to 3000 psi, and put out up to 7 GPM's. You are going far and above the designed limit by doing what you are doing.
In designing something, you have to set your expectations, and when those are achieved, and nothing has broken and it has been road tested, then you can say I have achieved my goal.
I think you should rethink about what you have and what it can do, and what you want to do with out anything breaking.
Right now on just the one motor, I think you are heating up the fluid by the relief valve, relieving above 1500 psi, and by running the motor at way above designed rpm, I think you will damage the motor. I have already said what the torque is on one motor running in the normal mode, and it did not seem enough.
The GPM's that your machine is pumping, is dependent on engine rpm. If you run is low rpm, you may not be giving the motor enough fluid to develop the torque. If you go to the Surplus Hydraulics website, then go to tech help, and select the pump and HP calculator, and then go back and select motor speed and torque.
As designed, the 3000 psi capability is developed by the load. Before when the 7 GPM pump was pumping 7 GPM through the three motors, and each motor could develop up to a 1500 psi load on the pump. Those 1500 psi relief valves is designed to protect the motor, so any time you force the blades to work hard, the blade and motor is putting a load on the pump, and if the pressure builds up to 1500, and if you continue to work it harder than designed, the relief will go off, dumping pressure and fluid until the pressure is below 1500. You are defeating the purpose of your mower is you try and force it to do more. If you put a gage on the motor or relief valve, you can see about when you are using the motor at full potential.
One of those hyd pumps will operate up to 3000 psi, and put out up to 7 GPM's. You are going far and above the designed limit by doing what you are doing.
In designing something, you have to set your expectations, and when those are achieved, and nothing has broken and it has been road tested, then you can say I have achieved my goal.
I think you should rethink about what you have and what it can do, and what you want to do with out anything breaking.
Right now on just the one motor, I think you are heating up the fluid by the relief valve, relieving above 1500 psi, and by running the motor at way above designed rpm, I think you will damage the motor. I have already said what the torque is on one motor running in the normal mode, and it did not seem enough.
RJA.Ilex
New member
Robert128
Can you please post a higher resolution copy of the hydraulic diagram.
If I am reading it right then R1A and R1B are the motor relief valves and as they are set to 3000psi that is what you are stalling on the single deck. Can you measure the blade speed at all? if you can then please check this as below a tip speed of ~60m/s (65m/s is ~13000ft/min) the cutting action of a rotary mower changes and requires more energy.
The blades are stalling sooner at at lower revs due to them having less inertia.
Can you make a smaller cutting blade (flat mild steel bar will do for prototyping work) and try cutting with this?
I think R3 is to prevent the motor destoying its seals when the cutters are turned off it allows them to free wheel. I am not clear on how they work but I have seen 3000psi when stalling 1 similar motor on an ar3. J.J. any views on this.
Can you please post a higher resolution copy of the hydraulic diagram.
If I am reading it right then R1A and R1B are the motor relief valves and as they are set to 3000psi that is what you are stalling on the single deck. Can you measure the blade speed at all? if you can then please check this as below a tip speed of ~60m/s (65m/s is ~13000ft/min) the cutting action of a rotary mower changes and requires more energy.
The blades are stalling sooner at at lower revs due to them having less inertia.
Can you make a smaller cutting blade (flat mild steel bar will do for prototyping work) and try cutting with this?
I think R3 is to prevent the motor destoying its seals when the cutters are turned off it allows them to free wheel. I am not clear on how they work but I have seen 3000psi when stalling 1 similar motor on an ar3. J.J. any views on this.
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RJA.Ilex
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I have done some number crunching and assuming you still have all the flow from both pumps running to the 3 motors in series then you should have enough flow for 20 inch blades staying above 13000ft/min (65m/s). this should give reasonable cutting performance while redusing the chance of stalling the motors when cutting. allowing a 2 inch overlap on the decks this gives a cutting width of 4.5 feet. I don't know I this is wide enough for you Robert128. How wide is the base machine?
