Controlling Hydraulic Motors With a 3rd Function Valve

[dfkrug]

Adding a crossover relief valve, similar to yours, is what I am planning to do. I'm looking at this Prince model:

Prince DRV Relief Valve DRV-4HH - Dalton Hydraulic

The implements I have and plan to build have no momentum issues so the valve should protect the hyd. motor and circuit. For any furure implements that have heavy spinning iron, I'll run a separate set of hoses and use a rear remote.

That Prince valve should work fine, and it has adjustable relief pressure. It serves to limit the pressure to your
hyd motor while driving it and kill pressure spikes when stopping it. It is also a large valve that allows flow-
thru for the work ports at high volume (30GPM).

The reason I went the direction I did with the Hydraforce valve is that it is considerably smaller and does
not have to be mounted anywhere. It also was less than 1/2 the price of the Prince. It has fixed RV
and no flow-thru.

Note that when making custom implements that use hyd motors, the most economical motors
for sale will usually be design-limited to 2000 psi (e.g. Charlynn S). To get motors that can
handle the full pressure of your tractor (usually 2500psi for the latest iron), you will need RV
protection like this. Hyd motors that can handle 2500psi and more will be a lot more expensive.

I ran my hyd PHDs slow, as I said, but I waited a while to get a good large hi-pressure motor at
a decent price (7ci White 255). I loved the instant-stop and reversible features.

 

[David_Kb7uns]

Although I have W&R Long 3rd function valves on both my tractors, I'm by no means experienced with their use. I have read that these valves are designed mainly for use with hyd. cylinders, not motors. Holding the valves open for extended periods of time can cause overheating both from oil flow and the electric coils that hold the valve open. The manual warns against this but doesn't give specifics.

I plan to build or buy a few implements that use hyd. motors like a sweeper, post hole digger, brush cutter and a cement mixer. Has anyone here had any experience with extended 3rd function hyd. motor use?

From Everything Attachments web site regarding the WR Long 3rd function valve.

"Our valve is made for momentary use like open / close or left / right operation. It is not made for rotary implements like augers. The valve has a extremely tight tolerance and if held down to use a rotary attachment it will heat up and swell causing the valve to seize. Thanks!

-Josh Nabb, W R Long, Inc. "



David

 

[bdhsfz6]

From Everything Attachments web site regarding the WR Long 3rd function valve.

"Our valve is made for momentary use like open / close or left / right operation. It is not made for rotary implements like augers. The valve has a extremely tight tolerance and if held down to use a rotary attachment it will heat up and swell causing the valve to seize. Thanks!

-Josh Nabb, W R Long, Inc. "



David

Thanks for posting this.

My W&R Long manual says pretty much the same thing. It doesn't give use limits though, it simply warns against using it for "Continuous duty". This raises the question of how long is too long. The hyd. motor applications I have in mind, like a winch or mixer, have duty cycle times of less than 5 minutes. Would the valve overheat when using it to control a large hyd. cylinder with a long cycle time? $800 was a lot of money to spend for a valve which is limited to controlling only small cylinders on implements like a grapple, plow or 4 in one bucket.

In any case, I appreciate all the comments. I do plan on running a second set of hoses to bulkhead fittings on the FEL which will connect to a rear remote. Had I known what I do now, I would have saved the $800 and done this in the first place.