Rip - Your Chipper

[J_J]

Rip,

The free wheeling motor that you mentioned in an earlier post, would have to have a motor spool valve in the circuit to allow it to coast to a stop. If not, the motor would destroy it self if you stopped it all of a sudden. I am guessing that the PTO operated instant on valve is that kind of valve. My PTO valve is manually operated, and can operate at any speed. When I shut down the stump grinder, the blade is still spinning for a couple of minutes. The same with all the other motor driven attachments.

 

[Rip]

Yeah....that's why I suggested checking with Terry to see if the electric solenoid PTO valve had such a bypass feature built-in. It may be that some motors have an internal bypass, if so I have not heard of it.

Something does need to allow the fluid flow, induced when the high-inertia spinning load causes the motor to act like a pump, to recirculate. So if the PT system does not already provide for this, my external oneway-check valve does.

 

[ponytug]

On my 1445, the PTO definitely freewheels, when off. It takes quite some time for the mower to spin down.

Like other have suggested, I engage the PTO at idle and then slowly power up, but I turn the PTO off at speed, otherwise, you can hear the mower pushing the engine, which can't be as good as just letting it freewheel.

All the best,

Peter

Yeah....that's why I suggested checking with Terry to see if the electric solenoid PTO valve had such a bypass feature built-in. It may be that some motors have an internal bypass, if so I have not heard of it.

Something does need to allow the fluid flow, induced when the high-inertia spinning load causes the motor to act like a pump, to recirculate. So if the PT system does not already provide for this, my external oneway-check valve does.

 

[MossRoad]

Have you thought about just getting a hydraulic motor with a standard 6 spline pto shaft on it and driving the chipper with a short drive shaft?

Something like the three motors listed in this link at Surplus Center?

 

[woodlandfarms]

So, yes, I was initially looking at those PTO motors. But then JJ put up that other pump and now I am confused. In Hydraulics, what is the difference between a pump and a motor.

The one JJ showed would be quite cool and easy to use on multiple devices. The PTO Motors as Moss recommended would need some finagling.

That all said, Rip suggests direct connection but I do need to check the Hydraulic feeders situation first...

 

[J_J]

So, yes, I was initially looking at those PTO motors. But then JJ put up that other pump and now I am confused. In Hydraulics, what is the difference between a pump and a motor.

The one JJ showed would be quite cool and easy to use on multiple devices. The PTO Motors as Moss recommended would need some finagling.


Carl,

If you are trying to power a chipper on the front of your machine, the PTO motors would be the way to go. I thought you mentioned about putting something on a PTO shaft, I was thinking about the PTO shaft on the back of a tractor, as an extra source of hydraulic power. Someone makes a unit that is mounted on a frame hooked up to a skid steer to power 3pt implements. It could easily be adapted to the QA on the PT.


A hydraulic pump is used to generate the pressure and flow for use in a hydraulic system. A hydraulic motor uses that pressure and flow to develop HP . Some hydraulic motors can be used as pumps. You have an 18 gpm pump just for the PTO application. That pump runs all the time. If the PTO fluid is not being used by the hydraulic motors, it goes back to tank. A lot of wear and tear on the pump, but that is the way PT built the PTO system. You have the potential of 38 HP being produced by the PTO pump. All you have to do is find a hydraulic motor and a chipper that will use that HP, and you have a hydraulic powered chipper. Some of those chipper wheels weigh 30 or 40 lbs. You need the velocity, torque and HP to have a workable chipper.

 

[Rip]

From what Peter says, it sounds like the PTO valve does allow for the motor-generated flow to not be dead-headed, so my bypass check-valve was probably not needed.

In brief, there are many many types of hydraulic pumps and motors all designed to be better for certain applications than other types. Some motors can and will "act" as a pump when driven by their load such as a hoist with a suspended load or a heavy spinning chipper flywheel (which in the case of the Betst WC-6 chipper may well be 150 lbs).

That said, pumps are designed to be pumps, and motors to be motors. I doubt you will ever see a single item listed as both a pump and a motor.


Whenever power is run through a speed-up or step down system of belts, gears, or such, there is power loss. This can easily be 20 to 30%. While it would be possible to set up a hydraulic motor to power the PTO input of the chipper at 540 Rpm, it would not be efficient. I've seen the units JJ is refering to above, and it would cost more than the chipper you are looking at, but would power many other 3 pt tractor PTO attachments if that is of interest to you.

Direct-driving the chipper disc at nominal 2000 RPM via a flex coupling would be the best method and is how any Skid Steer chipper is powered.

I did look up the model you are looking at Carl, and did not see one already set up for hyd drive. The power feed also looks like it is mechanically driven rather than hyd, so that would be one less thing to have to modify. This would be a pretty good project and involve some engineering, welding and machining. To the extent you could do it all yourself, it may take a week or so and $650.

 

[woodlandfarms]

JJ. thanks for the clarification. I was all excited about an easy fix but this can work....

I have been looking at teardowns of the Jinma and it looks like hooking a motor up directly like Rip did will not be that hard. I am wondering should some sort of meshing block be used or just a hard coupler... Here are some pix....

http://www.ranchhandsupply.com/woodchipper/woodchippertipspictures.html

If I do go with a direct connect going at around 2000 RPM...

Anyone have a suggestion on a motor that is 2000 RPM and rated for my system?

 

[Rip]

Carl, Yes it is pretty straight forward, but the motor mount will have to be welded (can still just bolt to the chipper housing though) and machined as it must be perfectly lined up with the disc shaft.

You have to use a LoveJoy or other brand of flex coupling between the hyd motor and disc shaft to allow for the slight missalignment and vibration that will occur. This coupler will also allow for different shaft diameters between the chipper disc and the motor. The type and brand is not important, just that it is rated for more than the HP & torque being put through it.

I'de have to do some research on the motor, although there are quite a few that would work.

By the way.....there are a few "pump/motors" out there where the same iten is rated as either a pump or a motor. The rare exception, but they do exist.

 

[ldabe]

...lovejoy, spool, deadhead, etc., etc., etc., ....WOW!

No matter what it is called, it's all "overmyhead"! (LOL)

But, it is interesting to read, and who knows, an old dog may learn a few new tricks ;~)