SnowRidge
Elite Member
There isn't any. That's why the engine stalls if the machine is pushing or pulling the immovable object and has good traction.
More torque for my Power trac?
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There isn't any. That's why the engine stalls if the machine is pushing or pulling the immovable object and has good traction.
J_J
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Please read my update in my previous post..
SnowRidge
Elite Member
Did you ask him about a high pressure relief valve? The relief valve in the Sauer Danfoss pump is for the charge pump.
If there was a relief valve for the wheel circuit, the engine wouldn't stall under an excessive load.
J_J
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If the relief is not set correctly, the HP suppled to the pump will deplete at max rpm, and the engine will stall. If the engine had enough HP, it would force the pump to relieve, or explode. That is written in stone.
J_J
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If I remember right, some of the 425 owners said that the engine stayed running, and it just grunted in a tough situation. To me that sounds like that some relief valves are working on the 425.
woodlandfarms
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There has to be a relieve valve. Reasoning is...
If the pump is built tight enough to create 2500 PSI, and is direct drive, then when the pump hits an imoveable object (ie oil with no place to go) the engine and pump stop dead. The oil has no place to go and that sudden shock will cause an explosion, not a bog.
If I am running my tractor and flip on the PTO with nothing attached, the engine will bog, and bog bad, maybe stall depending on variables. But still, there is a relief valve.
The only way I could see that the pump does not have a relieve valve is that the pressure relief is in the tram configuration. That the oil goes through the forward and reverse circuits when pressure is needed to be relieved.
But what do I know... I can get an actor to show up, and have the camera pointed the right way. End of high paid skill set.
If the pump is built tight enough to create 2500 PSI, and is direct drive, then when the pump hits an imoveable object (ie oil with no place to go) the engine and pump stop dead. The oil has no place to go and that sudden shock will cause an explosion, not a bog.
If I am running my tractor and flip on the PTO with nothing attached, the engine will bog, and bog bad, maybe stall depending on variables. But still, there is a relief valve.
The only way I could see that the pump does not have a relieve valve is that the pressure relief is in the tram configuration. That the oil goes through the forward and reverse circuits when pressure is needed to be relieved.
But what do I know... I can get an actor to show up, and have the camera pointed the right way. End of high paid skill set.
J_J
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Snowridge,
Do you have the Danfoss series 15 VSP pump?
Do you have the Danfoss series 15 VSP pump?
J_J
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Carl,
There is a good reason for the situation with the PTO pump. With the engine running and using tram pump and steering pump, there is some HP left to run the PTO pump under normal condition. But like you said you fail to plug the QD up. You are now asking that diesel to cough up some some extra HP to overcome the new imposed load, deadhead. If the PTO relief don't go off, the pump will blow, or the engine will die.
There is one small chance that I can think of that the system would have no relief valve. That is when there is not enough HP to power the pump to get it up to the test pressure, and what happens then, is the engine bogs down because it is trying to make pressure and but just don't have the guts to do it. If other things were stopped like steering, or lift, PTO, some more HP would be available to unbog the engine. Several of the owners have mentioned about cutting off the PTO just to get up the hill.
There are some Danfoss pumps that do not have relief valves, because the end receiver will install their own. They are an option, and in my opinion, necessary. There is also some logic to the fact that if you have a habit at bogging the motor out a lot, The life cycle of the pump and engine will diminish.
There is a good reason for the situation with the PTO pump. With the engine running and using tram pump and steering pump, there is some HP left to run the PTO pump under normal condition. But like you said you fail to plug the QD up. You are now asking that diesel to cough up some some extra HP to overcome the new imposed load, deadhead. If the PTO relief don't go off, the pump will blow, or the engine will die.
There is one small chance that I can think of that the system would have no relief valve. That is when there is not enough HP to power the pump to get it up to the test pressure, and what happens then, is the engine bogs down because it is trying to make pressure and but just don't have the guts to do it. If other things were stopped like steering, or lift, PTO, some more HP would be available to unbog the engine. Several of the owners have mentioned about cutting off the PTO just to get up the hill.
There are some Danfoss pumps that do not have relief valves, because the end receiver will install their own. They are an option, and in my opinion, necessary. There is also some logic to the fact that if you have a habit at bogging the motor out a lot, The life cycle of the pump and engine will diminish.
MossRoad
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My PTO circuit has reliefs. I know that as I can see them and, if you have the PTO hoses disconnected and accidentally hit the PTO switch, you hear the engine growl and the relief open and you shut everything down quick.
My drive circuit, I have no idea if there are reliefs or not. As I've stated in other posts, I've never heard a relief open in the drive circuit. A few times I have slammed into immovable objects such as hidden tree stumps under a sand pile and it will instantly kill the engine.
If I push up against an immovable object on purpose and step on the go pedal the tires will break lose and spin most of the time as I have turf tires. If, however, I have incredible traction, the engine will bog down to the point that it will kill it. If there are reliefs in the drive circuit, they are set higher than the point that the engine can provide enough power to push the fluid past the reliefs.
BTW, this is a 2001 model PT425 with the Kohler Command 25HP engine.
My drive circuit, I have no idea if there are reliefs or not. As I've stated in other posts, I've never heard a relief open in the drive circuit. A few times I have slammed into immovable objects such as hidden tree stumps under a sand pile and it will instantly kill the engine.
If I push up against an immovable object on purpose and step on the go pedal the tires will break lose and spin most of the time as I have turf tires. If, however, I have incredible traction, the engine will bog down to the point that it will kill it. If there are reliefs in the drive circuit, they are set higher than the point that the engine can provide enough power to push the fluid past the reliefs.
BTW, this is a 2001 model PT425 with the Kohler Command 25HP engine.
