hydraulic motor hookup

[cowsrus]

Just wanted to check with someone who knows more about hydraulics than i do. I bought the digger part off of an old trencher at an auction and its powered by a hydraluic motor and i want to put a 3 pt hitch on it and use it behind my tractor.It's got two hydraulic connections on it. I'm thinking that you only have to hook up one of the hoses to the tractor and run the other hose into the tractors hydraulic reservior. Thats the way a post driver that i rented worked. Am i correct in my thinking?

 

[kennyd]

That will work for turning the motor only one-way. If you need to reverse the motor for any reason you can hook up both hoses to the rear remote-that is the best option IMHO.

 

[cowsrus]

What i was thinking that if you hooked up both hoses to the rear outlets on the tractor you wouldn't have a continuous flow through the pump and that it wouldn't turn unless you did.

 

[SPYDERLK]

That will work for turning the motor only one-way. If you need to reverse the motor for any reason you can hook up both hoses to the rear remote-that is the best option IMHO.

If you do hook up both hoses you will run some risk of motor damage when you stop the motor with the valve. This is because the valve ports will be blocked suddenly when the valve closes. The motor lines become isolated and the motor must stop instantly. If the motor is driving any significant inertial mass that inertia will try to keep the motor spinning as a deadheaded pump. Tremendous pressure will result causing damage. Special motor control valves, that allow flow in the motor lines to continue as the motor stops, are sold for this purpose. There are also relief valve sets that can be put in the motor lines to allow use of the std remote valves safely. Possibly, if your remotes have a float function you could just always switch to float when stopping to allow a graceful stop.
larry

 

[kennyd]

Not sure what "outlets" you have...Is there a lever that controls them? Are the "outlets" coupled together?

If it's a "rear remote", then there is a lever that sends fluid to the QD's (quick disconnects) with this lever you would have directional control of the motor.

If the two "outlets" are coupled together, then what you have is called a "power beyond" loop that has a continuous supply of oil in them whenever the tractor is running-it's used for implements like backhoes and logsplitters that have their own valves.

If you have the power beyond setup-then you will need a valve to control the motor anyway...

 

[kennyd]

If you do hook up both hoses you will run some risk of motor damage when you stop the motor with the valve. This is because the valve ports will be blocked suddenly when the valve closes. The motor lines become isolated and the motor must stop instantly. If the motor is driving any significant inertial mass that inertia will try to keep the motor spinning as a deadheaded pump. Tremendous pressure will result causing damage. Special motor control valves, that allow flow in the motor lines to continue as the motor stops, are sold for this purpose. There are also relief valve sets that can be put in the motor lines to allow use of the std remote valves safely. Possibly, if your remotes have a float function you could just always switch to float when stopping to allow a graceful stop.
larry

Yes, well aware of all that...he asked about a auger-they run slow so feathering the valve to off would suffice. But we are not even sure what setup he has just yet anyway.

 

[cowsrus]

I would be hooking to a standard rear hydraulic outlet used to power implements where the control levers operate one or the other outlet. I have a John Deere 4230 tractor or a International 886. Both are about 100 hp tractors

 

[cowsrus]

BTW-Its a trencher for digging a ditch i'm going to hook up.

 

[SPYDERLK]

Yes, well aware of all that...he asked about a auger-they run slow so feathering the valve to off would suffice. But we are not even sure what setup he has just yet anyway.

???
larry

 

[cowsrus]

To help clarify what i'm trying to do: The hyd motor has two hose connections on it and i was thinking that the fluid had to run through the motor in order to make it turn. If i hooked the two motor connectors to the two tractor remotes, i didn't think it would work that way. Will the motor turn if only hooked up to one of the outlets? I only need it to turn one way.

 

[kennyd]

???
larry

OK , trencher-not auger. Same difference.

 

[kennyd]

I would be hooking to a standard rear hydraulic outlet used to power implements where the control levers operate one or the other outlet. I have a John Deere 4230 tractor or a International 886. Both are about 100 hp tractors

Then you have no problem. One hose to each QD, and operate the lever for control.

Be sure to let the handle back to neutral (center) slowly to alleviate the problem that Spyder mentioned.

What i was thinking that if you hooked up both hoses to the rear outlets on the tractor you wouldn't have a continuous flow through the pump and that it wouldn't turn unless you did.

You will have flow when the lever is moved from neutral. If the attachment has it's own valve (I am a bit unclear what you have exactly) then you can just bungie the handle open after the connections are made BUT you must make sure it has a OC (open center) valve on it so the fluid can freely flow through the valve when it's in neutral. You can verify that with air pressure.

 

[cowsrus]

The trencher attachment does not have its own valve, it will be totally operated by the tractor remote levers.

 

[J_J]

I believe a PB addition using a motor spool valve with detent, would be the best way to go. That way, yo;u will probably have some relief protection, and the ability to reverse if you ever use an auger. You could also use one of these.

Motor spool valve with detent and relief. Controls both directions

https://www.surpluscenter.com/item.asp?UID=2009100506094663&item=9-7497-30&catname=hydraulic

Variable speed valve. One way.

https://www.surpluscenter.com/item.asp?UID=2009100506094663&item=9-4169-10&catname=hydraulic