JJ and others - Post Hole Digger

[J_J]

Hey JJ,

Quick Q. On the product description of this valve it says that there is no neutral position, which confuses me and makes me think if I use this valve it's either forward or reverse, with no off setting.

I'm thinking of using a PTO driven system, and I'd like to leave the PTO on all the time and just use a 3 position toggle for forward/off/reverse as you describe.

Thanks,

-Jer.

In a motor spool valve, the off position is a freewheel position where the fluid is allowed to circulate until the motor energy is expended. If you closed off the fluid from a hydraulic motor turning at high speed, the total energy in that motor would either burst the motor, blow a line, or valve, assuming that a relief valve of some kind is not installed. I have seem a double relief valve on one of the TBN members hydraulic setup.

You mention leaving the PTO on, I don't believe that is a good idea because the hydraulic motor would start turning as soon as you started the tractor.

On the electric valve, you would only need a two position switch, position 1 would operate the solenoid to allow FWD motor speed, With no power applied, the spool is in a neutral position and fluid is at rest or slowing down. At position 2, the motor turns in REV flow, which might be used in an auger back-out situation.

Below is a manual motor spool valve that will allow you the same FWD, and REV setup.

Burden Sales Surplus Center Item Detail

You probably would want one with detent.

 

[jgrreed]

In a motor spool valve, the off position is a freewheel position where the fluid is allowed to circulate until the motor energy is expended. If you closed off the fluid from a hydraulic motor turning at high speed, the total energy in that motor would either burst the motor, blow a line, or valve, assuming that a relief valve of some kind is not installed. I have seem a double relief valve on one of the TBN members hydraulic setup.

You mention leaving the PTO on, I don't believe that is a good idea because the hydraulic motor would start turning as soon as you started the tractor.

On the electric valve, you would only need a two position switch, position 1 would operate the solenoid to allow FWD motor speed, With no power applied, the spool is in a neutral position and fluid is at rest or slowing down. At position 2, the motor turns in REV flow, which might be used in an auger back-out situation.

Below is a manual motor spool valve that will allow you the same FWD, and REV setup.

Burden Sales Surplus Center Item Detail

You probably would want one with detent.

That's what I thought too. Would it be reasonable to add a simple on/off valve upstream from the reverser valve to allow for on/off, or is there such a thing as a combined electrovalve that has ff/off/rr all in one unit?? The reason I'm pushing for it is that I'm brainstorming/planning for an electrohydro system all controlled from grip mounted rockers and pushbuttons.

My PTO is on a safety system that turns off when I get off the seat, or turn the tractor off, so that's not a concern.

Thanks for the response, appreciate it.

-Jer.

 

[jgrreed]

In a motor spool valve, the off position is a freewheel position where the fluid is allowed to circulate until the motor energy is expended. If you closed off the fluid from a hydraulic motor turning at high speed, the total energy in that motor would either burst the motor, blow a line, or valve, assuming that a relief valve of some kind is not installed. I have seem a double relief valve on one of the TBN members hydraulic setup.

You mention leaving the PTO on, I don't believe that is a good idea because the hydraulic motor would start turning as soon as you started the tractor.

On the electric valve, you would only need a two position switch, position 1 would operate the solenoid to allow FWD motor speed, With no power applied, the spool is in a neutral position and fluid is at rest or slowing down. At position 2, the motor turns in REV flow, which might be used in an auger back-out situation.

Below is a manual motor spool valve that will allow you the same FWD, and REV setup.

Burden Sales Surplus Center Item Detail

You probably would want one with detent.

That's what I thought too. Would it be reasonable to add a simple on/off valve upstream from the reverser valve to allow for on/off, or is there such a thing as a combined electrovalve that has ff/off/rr all in one unit?? The reason I'm pushing for it is that I'm brainstorming/planning for an electrohydro system all controlled from grip mounted rockers and pushbuttons.

My PTO is on a safety system that turns off when I get off the seat, or turn the tractor off, so that's not a concern.

Thanks for the response, appreciate it.

-Jer.

 

[J_J]

That's what I thought too. Would it be reasonable to add a simple on/off valve upstream from the reverser valve to allow for on/off, or is there such a thing as a combined electrovalve that has ff/off/rr all in one unit?? The reason I'm pushing for it is that I'm brainstorming/planning for an electrohydro system all controlled from grip mounted rockers and pushbuttons.

My PTO is on a safety system that turns off when I get off the seat, or turn the tractor off, so that's not a concern.

Thanks for the response, appreciate it.

-Jer.

You do not need another valve to shut things off, as the fluid in the neutral position is going back to tank, otherwise, the gear pump is pumping, and the fluid has to go somewhere, and when not used, it returns to tank. As soon as you throw the switch of shift the lever, you put some resistance in the hydraulic circuit and pressure builds up and things start to work as advertise. In my PTO circuit, I have a mechanical lever that regulates speed of the hyd motor, and the left over fluid goes back to tank. Other people have a solenoid valve in their PTO circuit, and when switched on, the motor is up and running at max speed. There is some speed control by varying the speed of the engine.

 

[jgrreed]

You do not need another valve to shut things off, as the fluid in the neutral position is going back to tank, otherwise, the gear pump is pumping, and the fluid has to go somewhere, and when not used, it returns to tank. As soon as you throw the switch of shift the lever, you put some resistance in the hydraulic circuit and pressure builds up and things start to work as advertise. In my PTO circuit, I have a mechanical lever that regulates speed of the hyd motor, and the left over fluid goes back to tank. Other people have a solenoid valve in their PTO circuit, and when switched on, the motor is up and running at max speed. There is some speed control by varying the speed of the engine.

Sorry for the double post.....

OK, I think I understand. So there is no 'neutral', but off is basically the same thing, because in the 'off' position, all flow cycles straight back to the reservoir.

So with that set up I could have a 3 position rocker with forward/off/reverse??

-Jer.

 

[J_J]

Sorry for the double post.....

OK, I think I understand. So there is no 'neutral', but off is basically the same thing, because in the 'off' position, all flow cycles straight back to the reservoir.

So with that set up I could have a 3 position rocker with forward/off/reverse??

-Jer.

Yes to the switch, but it should lock in all three positions. and I would still add a relief valve for the motor, in case you inadvertently flipped the switch to reverse while the motor is winding down. In that situation, the motor would act like a pump, and when you flipped the switch, you would apply full hydraulic pressure to fluid coming from the motor, causing problems.

 

[jgrreed]

You do not need another valve to shut things off, as the fluid in the neutral position is going back to tank, otherwise, the gear pump is pumping, and the fluid has to go somewhere, and when not used, it returns to tank. As soon as you throw the switch of shift the lever, you put some resistance in the hydraulic circuit and pressure builds up and things start to work as advertise. In my PTO circuit, I have a mechanical lever that regulates speed of the hyd motor, and the left over fluid goes back to tank. Other people have a solenoid valve in their PTO circuit, and when switched on, the motor is up and running at max speed. There is some speed control by varying the speed of the engine.

Sorry for the double post.....

OK, I think I understand. So there is no 'neutral', but off is basically the same thing, because in the 'off' position, all flow cycles straight back to the reservoir.

So with that set up I could have a 3 position rocker with forward/off/reverse??

-Jer.

 

[J_J]

Jgrreed,

Check out these pictures from some of our members, concerning relief valves.

Post #6, and #9

http://www.tractorbynet.com/forums/hydraulics/129185-what-happens-fluid-neutral-position.html

 

[jgrreed]

Really sorry for the repeat posts. I'm at my in laws and their dialup keeps cutting out.....

We're signing them up for high-speed, they just don't know it yet!!!

-Jer.