I would like to know more ???

[oldnslo]

What type of spool does the FEL valve have? If it is the series type fluid from the FEL cylinders will also be sent downstream via the power beyond port. I believe Kubota used this on some models so that you can raise the FEL at full flow and still dump the bucket.

This would explain the slowing down while raising and speeding up while lowering do to the area differences in the FEL cylinders.

 

[ns_in_tex]

About 10 years ago, we converted a 30" mower deck to be powered by this hydraulic motor, so we could mount it on our FEL & mow places we could not otherwise reach. It worked great, but as you know, we sometimes, (no always) will push something that is working good, beyond it's limits. SO, nearly every year, we do upgrades to make it do a little more. It no longer has anything original except the motor. This year is no different, we decided we wanted to replace the bush hog type blade with a 29" saw blade which we had on hand.

We tried it out the other day, not knowing what to expect, but it was amazing what it would do, trimming limbs off the side of trees.

Night put a stop to that testing and we had a oil leak at a fitting, so we took it to the shop to repair the leak.
After sleeping on my situation, we have decided our spindle, shaft and blade mounting is unsafe. I think we need a heavier spindle & blade mount. I don't think we will use the saw blade as mounted now. The spindle is one we removed from a discarded Woods RM306-1 finish mower.

I am now trying to come up with a heavier spindle. Will welcome any suggestions.

Back to the hyd flow. I remember when we bought this tractor, one of the reasons we chose it was because it was a new model that had been optimized for FEL use. Our unit will dump while lifting and would bet a 5.00 bill that the motor speeds up while the FEL is lowering. I just don't understand why, or how much. In my opinion, this is a good thing for my situation. Cutting limbs from top = lowering loader = more GPM = more RPM = run the engine slower while working.

Our tractor pump is 9 GPM at full throttle, but we like to run it from 1300 to 1800 rpm. Relief valve is 2550 psi on tractor and we have an adjustable plumbed in the motor lines and is set something less than 1800 psi.

I expect to be out of operation for a while, as we come up with parts for our next upgrade.
Wish me luck, I may need it.

 

[teg]

Neal, Got Photos???

 

[oldnslo]

Back to the hyd flow. I remember when we bought this tractor, one of the reasons we chose it was because it was a new model that had been optimized for FEL use. Our unit will dump while lifting and would bet a 5.00 bill that the motor speeds up while the FEL is lowering. I just don't understand why, or how much. In my opinion, this is a good thing for my situation. Cutting limbs from top = lowering loader = more GPM = more RPM = run the engine slower while working.

Our tractor pump is 9 GPM at full throttle, but we like to run it from 1300 to 1800 rpm. Relief valve is 2550 psi on tractor and we have an adjustable plumbed in the motor lines and is set something less than 1800 psi.

I expect to be out of operation for a while, as we come up with parts for our next upgrade.
Wish me luck, I may need it.

If your tractor was supplied wit ha valve "optimized" for FEL use you probably have a series spool like I stated earlier. This spool directs the flow returning from your lift cylinders downstream into the power beyond port.

Example: If your cylinder ration is 1.25:1 and your tractor puts out 10 GPM while raising you would only get 8 GPM flow in the power beyond circuit. While lowering you would get 12.5 GPM flow in the power beyond port.

 

[J_J]

I sure thought that most FEL valves were parallel based on the fact that you can do both lift and dump at the sane time.

I also thought that when you pushed the lever to max, the full pump flow is applied to the cyl until the cyl is maxed out and nothing goes downstream through the PB until the lever is released to neutral.

If you only use half lever, then some of the pump flow goes through the PB port.

If you keep the lever at max, the pump flow is diverted by the relief valve.

 

[oldnslo]

JJ,
Husco & probably other valve manufacturers offer a FEL control where the lift lower spool return flow is directed into the pressure / power beyond. I don't remember who but some one posted a schematic for Kubota with this option.

You are correct in that most FEL valves are parallel where you must feather the lift to get any flow for dump.

 

[ns_in_tex]

Thanks for the explanation. Now, at least there may be a reason for my thinking on the way it works.

We did order a new spindle, yesterday, which we hope will be more sturdy, and maybe a little safer to use with the saw blade. Should get it by Monday. Then we can get back to our next modification.
Does anyone know if there is a normal operating saw blade tip speed and also a speed which should not be crossed?
This is an old 29" steel blade, no added on cutting tips.

If your tractor was supplied wit ha valve "optimized" for FEL use you probably have a series spool like I stated earlier. This spool directs the flow returning from your lift cylinders downstream into the power beyond port.

Example: If your cylinder ration is 1.25:1 and your tractor puts out 10 GPM while raising you would only get 8 GPM flow in the power beyond circuit. While lowering you would get 12.5 GPM flow in the power beyond port.

 

[oldnslo]

Old buzz saw on the front of our 520 JD ran off the flywheel pulley. I believe the 520 ran around 1400 RPM but could be wrong. From memory the pulleys were very similar in size and the blade was at least 36" dia.

Don't know what the safety specs says on tip speed.

 

[dfkrug]

What type of spool does the FEL valve have? If it is the series type fluid from the FEL cylinders
will also be sent downstream via the power beyond port. I believe Kubota used this on some models so that you can raise
the FEL at full flow and still dump the bucket.

This would explain the slowing down while raising and speeding up while lowering do to the area differences in the FEL
cylinders.

I have never had that kind of valve, but it DOES explain what the OP saw, and I can see it's value on
a FEL. So, this valve has only one output port (power beyond), and no output to tank?

 

[oldnslo]

I have never had that kind of valve, but it DOES explain what the OP saw, and I can see it's value on
a FEL. So, this valve has only one output port (power beyond), and no output to tank?

No the curl dump circuit goes to tank and not the PB port & the raise lower connects both work ports to tank in the float position. I am going to try and attach a Husco valve document that shows this schematic. Ports 1A & 1B are the lift lower.