Fantastic explanation. Had never heard pressure expressed as "the amount of resistance being overcome by the pump". Thank you for clearing up this concept.
Dude, trump said the shit about pets, if he is that predictable and easy to manipulate…. I’m not saying to vote for Harris but I mean. How would this help trump
Helou i have mini digger libra 216S.. it loses presure slowly... When i lift boom it wil came to ground slowly when engine is running or not.. What do you think problem is ??? Thanks..
Great video , i would like to know , Can i deadhang the pump from the system if from the pump discharge it goes not only to a relief valve but a control block that contains a relief valve, a main spool etc, thanks.
Thank you very much for recording this video. I’ve found very few others that are actually helpful. I have a bobcat 863 that the auxiliary hydraulics lose pressure as the machine warms up. Any specific recommendations for this problem? Greatly appreciate your time.
Did you find answer to your problem, a have similar .. lose power - pressure slowly... If engine is running or not... Boom will come to ground slowly...
There is "no difference". You cannot seperate pressure and flow. Each one is the result of the other. A pump adds energy into the system. Hydraulic Energy is pressure x flow. How much of each one results is determined by how efficiently a pump can convert Energy to the pressure component of Energy, ie potential energy, and flow energy, ie kinetic energy. The pump's efficiency is strongly related to how much flow is running through it at any given time. At BEP, you get the best efficiency and the highest value of pressure x flow for the electric energy being supplied to the pump. At off BEP flows, low flows produce high pressures and high flows produce low pressures. Adding pipe and equipment into the system changes the resistance to flow and that causes the pump to change its efficiency, which causes a new Pressure x Flow output combination from the pump. You cannot seperate pressure, from flow, or resistance. Look at the hydraulic and electrical analogy. You will see that you are trying to separate amps and resistor and voltage. Electrical engineers do not ever try to separate them. Why bother, the result is the result of all three. Set any two Volts, Amps and you know the last, Ohms, one. Same for pressure, flow and resistance from pipe/valve/equipment. BTW, electrical valves are called transistors.
Great video, but I don't believe my pump has a compensator. I have a Roper Log Splitter that won't split anymore. The cylinder goes out, but will not push into the wood anymore. No leaks. So either its the pump, the actuator valve or the cylinder? Normally the actuator valve handle would self return to the neutral position when the cylinder fully retracts. It will not do that anymore either. When trying to push into the wood, the engine bogs down. It normally would bog down if it encountered a very hard piece of wood or at the end of cylinder stroke. Any thoughts or help would be much appreciated. I still have a lot of wood to split before winter.
Thanks for your question! You are correct, your pump has no compensator. Your pump is likely a gear pump. I'd be interested to know if your pressure is low, but I'm guessing you have no pressure gauge on your splitter, so you would not know if it was above or below normal even if you measured it, correct? I'm thinking your pressure is fine, though, because you say it is bogging down the engine. It wouldn't do that if your pressure was low, it would simply stall. First thing I would check is your relief valve. Probably you have no separate relief valve, but there would be one integral to the directional valve. Since you say that the valve handle no longer springs back, the relief valve sounds like the most likely culprit. You probably only need to clean it out. It is probably the only adjustment on the valve. WITH NO PRESSURE IN THE SYSTEM AT ALL, remove the components of the relief valve and clean everything, Put it all back together and test it. If that doesn't work, you may have to replace the whole valve assembly. Hope this helps!
@@JackWeeksThank you so much for your answer & insight. I'm not sure if it even has a relief valve. I wish I could post some pictures here. I'm gonna start by simply changing the filter to see if that helps. I'll look for a relief valve on the directional valve. The splitter is at my brother's right now. I'm gonna head over there shortly. What would be safe to use to clean the relief valve? Ether maybe? Or just some cloth?
@@JackWeeks also no guage. But I pulled a guage off of a different hydraulic unit. I have see if I can adapt it on with some fittings on hand. But yeah, I have no clue what the pressure should be.
@@Happy_Harry Definitely start by removing the directional valve, taking it apart and cleaning everything. Look for a built in relief valve and see if it is stuck open. Carburetor cleaner is good for cleaning these valves, just be sure to remove the cleaner with new hydraulic oil afterward. Good luck to you!
What type of accumulator do you have - bladder or piston? If it is a bladder accumulator, the bladder must be ruptured. If it is a piston accumulator, your piston seals may need replacing.
@@JackWeeks I had an argument about this, well, discussion really, with a guy who was supposed to be the supervisor. He didn't get that pumps that "do" high pressure, are simply capable of producing flow against a higher resistance than a low-pressure pump.
Jack i know this is a big ask so i understand if your not able. I have a hydraulic system (for you extremely basic) but would love to understand how the whole system works, not only for troubleshooting but also just to understand how it works. Would i be able to email you pictures/info and you could explain the operation. Again i know its a big ask so i understand if your unable but it never hurts to ask and i love understanding how a system actually works. Thanks in advance whichever your response is, im hooked on your teaching videos. Brian
Thank you for your kind comments! Yes, I would be glad to help. Email me any time at jack@fluidpowerlearning.com (GPM Hydraulic Consulting is no longer in business, so I am on my own now).
@Jack Weeks Jack you made my day more than you know. So i give as much info as possible i will email you tomorrow so i can get pictures together and as much info to give you as possible to try and save you as much back and forth as possible. I will include in the subject line pretty obvious its coming from me. You have me excited like a little kid Jack so thank you so much.
Quick question. So if you would open the flow control after the system checks out would the pressure now drop because of the load? My system reads 2600 psi with no load but when hooked up to the cylinder for an 4 post auto lift it falls to 800 psi. Cylinder has been rebuilt so that isn’t the cause. Just wondering why the lift seems to be running slower. Thank you for your help. Dan
Hi Dan. Thanks for your question. Yes, the pressure would drop once you open the flow control, assuming there are no other flow controls in the system. If the only resistance downstream is the load, then the pressure would drop to load pressure. However, if there are any flow controls limiting speed, the pressure would stay at the pump compensator setting since the stroke of the pump would be limited by the flow controls on the actuator. Hope this helps!
hello, I have the problem with my pump, every time I turn it on, it cant build up pressure but when I open the valve all the way open after 10 seconds it grabs hard and after that it works fine, like nothing ever happen. Can you help me solve the problem? I had this problem before I put new oil and new oil filter.
It's definitely caused by trash somewhere. Possibly the system relief valve not seating at first, or if you have a variable displacement pump, it could be the compensator valve. Try disassembling the relief and cleaning it. Same with the compensator valve if it exists in the circuit.
@@JackWeeks thanks for answering my question, here is a video from my channel if you want to take a better look on what the problem looks like ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-v-YKsQYDAq0.html
@@TrailMaker2 Yes, you definitely have some trash keeping either a relief valve or the compensator from seating properly. The trash is getting blown out and all is working properly in just a few seconds, then when it is shut down, lodging again and keeping pressure from building. The ideal thing would be to flush the system, but second best would be to remove and manually clean the compensator, relief valve, and even the directional valve (sometimes directional valves will have a built-in relief). Hope this helps!
I’ve got a 755 jd tractor I’m looking to buy a backhoe with a recommended psi of 300 more than my tractor says it will produce. Can I still use the attachment with 300psi less than it says it needs?
Probably not. If you are unable to build the necessary pressure, the backhoe may not move. And if it DOES move, it will certainly stall under heavy load.
Yes, if the flow drops significantly (more than 10% on most industrial machines) when the pressure is increased to normal system pressure, the pump is bad and must be replaced.
Thank you for your response! The pressure didn't drop because the directional valve downstream was closed. In this particular case, a closed center directional valve was used, so strictly speaking, the compensator and relief could have been set without closing the needle valve. We recommend that it be closed because so many different configurations are out there and someone may be using this video who has, for instance, a tandem center valve rather than the closed center valve in the demo system shown.
@Jack Weeks Thank you for the reply! So I have a vickers p.c pump and have it set to 1k psi. Relief is at 1300 or so. Are vickers pumps always noisy? If I dial the pump down to say 500psi it's a lot less noisy. Also, prime mover is maxed out at 50 amps when I have it set to 1000psi. Can that attribute to pump noise? 3 phase motor, data plate says 50 amps max. It's on a bagging machine, feeds product into bag, then presses it down, seals it etc. When the comp pump hits set pressure, it's maintaining set pressure so should the motor always pull x amount of amps? Thanks so much again.
@@bucksnortbumblefuk6872 A higher pressure will indeed contribute to noise, but it shouldn't be excessive. There may be some other issue as well, such as an air leak or blockage in the suction line, or worn bearings, depending on the sound it is making. The current draw of the drive motor will not be constant even though the pressure is maintained. Current will also change based on speed and load resistance as those change.
@Jack Weeks pump is new, but guy before me was cavitating it bad as i started my repairs with fixing the inlet/supply. Several fittings loose. Also there is a 90* bend in front of the pump I don't really like. Thanks again for the reply.
Very useful! I keep this video on a 'rewatch' playlist that I revisit every time I need to dig up some lost knowledge , and I've come to this one many times over the years but never commented. Thanks a lot Jack!!
Hi sir Jack thanks for teaching me something i didn't know about torque horsepower controller it amazing because didn't know where to start to set or increase flow as the system relief valve is settled 120 on kawasaki axial piston pump and the roller screen the rollers are running fast and oil is very hot you can cook meat with this hydraulic oil and just touching the tank your hands are burning also electric motor and pump they hot and tripping
Hi Charles. You didn't mention before that the oil was overheating. That may be a separate issue from the breakers tripping, Check to be sure that your pump compensator is set below your system relief. The relief valve in such a system should never open because it is usually only a backup in case the pump compensator fails to limit pressure. Make sure the relief valve is set high enough above the compensator that it does not dump. Your oil should cool down then.
Actually, upon rereading your original question, you clearly DID mention that the oil was hot, but apparently I chose to ignore that for some reason. Your whole problem is likely to be that someone turned the pressure up on the pump and got it set above the relief valve. See this video on setting them: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-jYPSwhAgvBM.html
How to set a kawasaki axial piston pump K3vg280 with torque horsepower on the hpu because it is the system trips while operating and where should I decrease flow or increase it on the controller
Hi Charles, thanks for your question! That pump should have a volume stop (manual volume limiter) on it. This is simply a screw that limits the travel of the swash plate. Turn it clockwise and that should make the system stop tripping.
