Thank you so much for this well-made and carefully explained video! I'm studying for our first test in fluid power systems, and solving a physics problem involving a variable displacement, pressure-compensated pump and our book is hopelessly inadequate at explaining how to adjust or overcome changes to the system. The problem involves someone increasing a load from 20 tons to 30 tons (system was designed for 20 tons) and we are tasked with determining if it will still function. The load is extended and retracted and we are given the bore and rod sizes, as well as a value of 2500psi setting for the main relief valve. Doing the math reveals the system is fine for extension pressure, but pressure builds beyond the 2500 psi upon retraction of the load. Not sure if I can just adjust compensator setting safely to the higher pressure needs... Hoping that other videos in this series will help me understand how to overcome this issue without changing components in our theoretical circuit.
First of all Thank you for your support We have pump rexroth a4vg 180 Mounted concrete pump after we state pump the pump not in 0 pistion move to one set after we change the parts move only 10 strok and than agine stack on one site
This is very helpful for me I am looking at a new job and its hydraulic maintenance. I have been reading up alot on the systems but this video really helped me to visually see and understand thank you.
Hi lunch box, we have piston pump in hydraulic system, when no operation pump build pr. 80 kg/cm2 as per we set. But when operation start pr. Goes to zero and till we can't stop operation of cylinder, pressure not increase and cylinder move slowly. When cylinder operation complete pr. Build up slow in 30 sec. Give your suggestions pls, any check point we do in our system.
First of all thank you very much for sharing this video. Could you upload a video on radial piston pump? It will be helpful for us to understand in detail the same like an axial piston pump.
sorry, i'm not a hydraulic expert, but what shown in this video no matter how much pressure in port "a", the piston (in the pump compensating) remain in it's position because the hydraulic force coming from port "a" against upper and below piston is equal. or perhaps, the piston below has hole(s) and act just as a stopper?
Around the 03:45 mark, when the needle valve is tightened and pressure rises to 430 psi and flow drops to 6.80 GPM. Does this mean that as you get close to the spring setting of the pressure compensator (500psi in this case), you can actually control the flow output of the pump by making fine adjustments on the needle valve? In other words, can the DR pressure controller (Rexroth terminology) spool move 'proportionally' as you approach the spring setting of the controller? Thereby allowing you to indirectly control flow to different actuators in a circuit by using multiple needle/flow control valves.
No, you cannot proportionally control flow output of a pressure compensated pump. As the system pressure nears the compensator section, the compensator spool hunts and the pumps swashes to provide just enough flow to overcome internal leaks and maintain pressure. Actuator speed controls need to be carried out downstream of the pump output with adequate flow controls.
As usual excellent video. Please keep on posting. I would like to ask that the Pressure Comoensator/ Pressure Override "solenoid operated" ? As the schematic in your video, on the right side shows that it is solenoid operated. Would anyone clarify please? Thanks for sparing your valuable time.
Thanks for your question. I am happy to answer. In the upper right-hand corner we see the complete and detailed, manufacturer's symbol for this pressure compensated pump. There is a 3-port, 2-position valve that looks much like many other typical directional valves. But this one is not solenoid operated as there is no solenoid symbol. The symbol for an electrical solenoid is a rectangle with a diagonal slash. In the case of this valve, we see a dashed line coming down from above, against one end of the spool symbol. This means that the valve is hydraulic pilot pressure operated. When enough pressure builds on that pilot line to oppose the adjustable spring (zigzag symbol with diagonal adjustability arrow) below, then the valve shifts. I hope that answer helps a little. Feel free to reply again. - Carl
We have a hydr power pack A4VSO DP500 . The tally plate says ' power setting = 392 Kw '. We have another pump same make / type, the power setting says 427 Kw. 1. How do I adjust the 427 Kw pump to run on the 392 Kw prime mover. Both pumps are otherwise identical in all respects. 2. What if the 427 Kw pump is run from a 392 or 410 kw prime mover. The input range of the pump given as 385 to 435 Kw.
It sounds like the pump has a power control, and this can only be setup or changed on a test bench. If you use the pump set at 427kW in palace of the pump with 392kW, you may overload the electric motor. However if the electric motor is rated higher than 427kW, you should be fine.
HI, I have problem with the A10VG45EP type pump. its equipped with the lift machine. machine is not working with normal drive speed and its not moving on the road ramp(allowed limit ).I checked the pressure with the gauge during the drive mode. Its showing only 110 bars. What is the reason for this issue. Please help us to solve the issue.
We will be launching the public site just as soon as it is ready - later this fall. Can't be more specific than that for now, but we will make an announcement when the time comes.
I just checked the website which I was waiting for a long time, to be honest I founded very interesting but its a shame that you are asking money already at the beginning of the stage without giving the chance to people to really " TASTE" of what is capable the website..its a pitty for that!
Did you try out our free content? Just click "I'm New" - no need to sign up for an account. We have 3 free sessions in Hydraulics, and 1 in Electrical. We think that a handful of free sessions should be enough for people to decide whether they'd like to buy more, or just stick with our free TH-cam videos.
I register a long time ago, like 3months ago..I fully agree that somethings/subjects cannot be teached for FREE as they already exist firms which are asking thousands of dollars for a 3-4 day course to learn hydraulics..my personal opinion as expressed before it was that basic hydraulic should be ALL for free then raise the price of it when you start to learn about intermediate/expert "mode" of them..Aniway I will still following you guys because you are great.Nobody its perfect :-)!
Good to know you registered - we will be sending out invitations later this week. In the mean time, do try out the 4 free sessions. As we add content throughout the year, we'll definitely be releasing more for free. Our big challenge right now is making back what it cost us to build the site (which has been in the works for almost 8 years now, if you can believe it), and what it costs us to make the free videos every week. So we do need to do as much as we can to encourage people to pay. Our overall goal is to make great content, but it's pretty expensive to do (as I'm sure you can imagine). I really appreciate your feedback - cheers!
Any one guide me regarding Rexroth A4VSO variable piston pump repair with new carriage kit piston shoe and cylinder pump has been generate the pressure as per require but not sustain properly on machine running
I AM ABOUT TO DEVELOP A 30 TON SERVOHYDRAULIC TESTING MACHINE, AND I HAVE SELECTED A 30 HP MOTOR AND 37 CM3/REV YUKEN PISTON PUMP. I AM CONFUSED WHETHER I SHOULD SELECT RADIAL OR AXIAL PISTON PUMP? CAN ANYONE HELP ME OUT? IF I HAVE TO SELECT AXIAL PISTON PUMP THEN I AM CONFUSED BETWEEN 1) PRESSURE COMPENSATOR TYPE 2) CONSTANT POWER CONTROL TYPE 3) LOAD SENSING TYPE.. KINDLY PLEASE HELP
Port D is the case drain line. When this line is running unusually hot, it often means that the pump pressure compensator setting has been adjusted above the setting of the system pressure relief valve. Please check that the system relief valve is set to the correct pressure, and pump pressure compensator too, as indicated by the machine manufacturer. Follow safe procedures, or acquire the services of a trained hydraulics technician to make these adjustments.
LunchBox Sessions what is the function of the valve compensator and how to set this,should be equal to the relief valve system or higher than the pressure relief valve system?my pump rexroth a10v140dflr/3
Hello, love your all your videos, I'm trying to understand prime mover rotation. It may sound simple of a question, but can't find the information anywhere. I have a Vickers PVH980-L... that has to hook up to a diesel motor. The manual state's "Shaft rotation, viewed at prime mover end: counterclockwise". Does that mean the output of the motor is counterclockwise or the input of the pump?
Mech E no system flow occurs when all directional valves are closed or when all flow valves are closed. When there is no consumption path for the pump’s flow, then the maximum pressure (compensator) can be set/adjusted. I hope that helps.
Good video but not too deep. I'm not sure if pump is Bosch Rexroth but one of my favorite the A10V or A10VSO doesn't look like this. The awash plate bias springs of Rexroth A10V series is parallel in the opposite side. Most variable pumps have extra functions that could optimally operate systems like maximum and minimum mechanical flow limiter. To adjust the settings of any variable pumps it's still advisable to use a suitable Relief valve. I will never have any hydraulic system without any Relief valve. Damn I wasted more than 10 years of studying deeply and experience in hydraulics.
The A10VSO is one of my favorites too. Would you believe that size 10 (smallest) of the A10VSO does look like this with the bias spring (without a piston) in direct opposition to the control piston? I could send photos of the pump disassembled on our workbench. But I do know what you mean. The size 18 and up are as you say, with bias spring/piston assembly in parallel to and on the other side of case from, the main control piston. We try not to over-complicate any one video - build up the learning in little chunks. I agree re: relief valve. I see lots of piston pumps with and without min or max flow limit screw. Can go either way. We have the A10VSO series in 3D with fly throughs and narrated video. With DR and DFR. Please do stand by :-) I didn't understand what you meant about the wasted 10 years.... Keep on learning, - Carl
Oh no... the piston is symmetrical on both sides... it will not lift up. It has to be a "piston" with the spring pushing it down, instead of this double sided valve...
Thanks for writing. I understand that you are having a hydraulic system issue. Can you provide more specifics? Is there an issue with engine stall caused by excessive hydraulic pressure? Please be very careful with any pressure setting or pump control adjustments.
You can probably skip 50% of the lesser-importance facts in a vid like this - you aren't speaking to completely braindead people, and if you were it would hurt them to watch it twice.
What a great video. The visual effect and the description was extremely helpful. Thank you
Thank you so much for this well-made and carefully explained video! I'm studying for our first test in fluid power systems, and solving a physics problem involving a variable displacement, pressure-compensated pump and our book is hopelessly inadequate at explaining how to adjust or overcome changes to the system.
The problem involves someone increasing a load from 20 tons to 30 tons (system was designed for 20 tons) and we are tasked with determining if it will still function. The load is extended and retracted and we are given the bore and rod sizes, as well as a value of 2500psi setting for the main relief valve. Doing the math reveals the system is fine for extension pressure, but pressure builds beyond the 2500 psi upon retraction of the load. Not sure if I can just adjust compensator setting safely to the higher pressure needs... Hoping that other videos in this series will help me understand how to overcome this issue without changing components in our theoretical circuit.
I really needed this. Knowledge is power.
Very helpful content!
Actually, this channel is very useful.
First of all Thank you for your support
We have pump rexroth a4vg 180
Mounted concrete pump after we state pump the pump not in 0 pistion move to one set after we change the parts move only 10 strok and than agine stack on one site
This is very helpful for me I am looking at a new job and its hydraulic maintenance. I have been reading up alot on the systems but this video really helped me to visually see and understand thank you.
Thanks brother. It's very helpfull video for hydraulic technicians .
Thank you so much for these video
Thank you very much for all the Info one can never learn enough in life
Thank you so much for making these great videos. They are the best ones I have seen.
It is really helpful for me , thank you.
Does a pressure compensated pump usually start up on full or zero displacement?
good explanation
hello So this is the best and clear understandable ones for pressure compensation, i need the same one for load sensing thanks
thanks mark good job
Very good video!!!
Hi lunch box, we have piston pump in hydraulic system, when no operation pump build pr. 80 kg/cm2 as per we set. But when operation start pr. Goes to zero and till we can't stop operation of cylinder, pressure not increase and cylinder move slowly. When cylinder operation complete pr. Build up slow in 30 sec. Give your suggestions pls, any check point we do in our system.
Really usefull video
Thanks
First of all thank you very much for sharing this video. Could you upload a video on radial piston pump? It will be helpful for us to understand in detail the same like an axial piston pump.
You did see our Axial Piston Pump video series here, yes? www.lunchboxsessions.com/explore/hydraulics/fixed-variable-displacement-pumps
I would love to see a video on 3 stage compensators on vane pumps and solenoid controlled compensators.
sorry, i'm not a hydraulic expert, but what shown in this video no matter how much pressure in port "a", the piston (in the pump compensating) remain in it's position because the hydraulic force coming from port "a" against upper and below piston is equal.
or perhaps, the piston below has hole(s) and act just as a stopper?
Nice videos, informative one.
Sir, can you review the uchida rexroth A10VD43SR pump with 2 piston pumps, how does it work, thank you sir
Around the 03:45 mark, when the needle valve is tightened and pressure rises to 430 psi and flow drops to 6.80 GPM. Does this mean that as you get close to the spring setting of the pressure compensator (500psi in this case), you can actually control the flow output of the pump by making fine adjustments on the needle valve? In other words, can the DR pressure controller (Rexroth terminology) spool move 'proportionally' as you approach the spring setting of the controller? Thereby allowing you to indirectly control flow to different actuators in a circuit by using multiple needle/flow control valves.
No, you cannot proportionally control flow output of a pressure compensated pump. As the system pressure nears the compensator section, the compensator spool hunts and the pumps swashes to provide just enough flow to overcome internal leaks and maintain pressure. Actuator speed controls need to be carried out downstream of the pump output with adequate flow controls.
Thank you
Good job
great video
nice video.thanks bro
Sir what problem my wheel loader Hitachi zw180 no power. While turning running
As usual excellent video. Please keep on posting. I would like to ask that the Pressure Comoensator/ Pressure Override "solenoid operated" ? As the schematic in your video, on the right side shows that it is solenoid operated. Would anyone clarify please?
Thanks for sparing your valuable time.
Thanks for your question. I am happy to answer.
In the upper right-hand corner we see the complete and detailed, manufacturer's symbol for this pressure compensated pump. There is a 3-port, 2-position valve that looks much like many other typical directional valves. But this one is not solenoid operated as there is no solenoid symbol. The symbol for an electrical solenoid is a rectangle with a diagonal slash.
In the case of this valve, we see a dashed line coming down from above, against one end of the spool symbol. This means that the valve is hydraulic pilot pressure operated. When enough pressure builds on that pilot line to oppose the adjustable spring (zigzag symbol with diagonal adjustability arrow) below, then the valve shifts.
I hope that answer helps a little. Feel free to reply again. - Carl
LunchBox Sessions Thank you Mr.Carl for your detailed explanation. Please keep on contributing with your valuable expertise.
This video was very helpful. It would have been more helpful if you provided a little more detail on what was happening in the control piston.
Otherwise everything was very easy to follow. Was there a more detailed basic function video that preceded this that I missed?
We have a hydr power pack A4VSO DP500 . The tally plate says ' power setting = 392 Kw '. We have another pump same make / type, the power setting says 427 Kw.
1. How do I adjust the 427 Kw pump to run on the 392 Kw prime mover. Both pumps are otherwise identical in all respects.
2. What if the 427 Kw pump is run from a 392 or 410 kw prime mover.
The input range of the pump given as 385 to 435 Kw.
It sounds like the pump has a power control, and this can only be setup or changed on a test bench. If you use the pump set at 427kW in palace of the pump with 392kW, you may overload the electric motor. However if the electric motor is rated higher than 427kW, you should be fine.
Sir I want To Know about how EDC pilot control works ?
1 Vedio on it please
HI, I have problem with the A10VG45EP type pump. its equipped with the lift machine. machine is not working with normal drive speed and its not moving on the road ramp(allowed limit ).I checked the pressure with the gauge during the drive mode. Its showing only 110 bars. What is the reason for this issue. Please help us to solve the issue.
Have you checked if the controller is supplying rated current to the prop solenoids? Has the stroke limited been incorrectly set?
What software package is this?
could you tell me how to obtain this software
Hi, Can I get the Caterpillar software without paying?
How long until your site is up and running?
We will be launching the public site just as soon as it is ready - later this fall. Can't be more specific than that for now, but we will make an announcement when the time comes.
I just checked the website which I was waiting for a long time, to be honest I founded very interesting but its a shame that you are asking money already at the beginning of the stage without giving the chance to people to really " TASTE" of what is capable the website..its a pitty for that!
Did you try out our free content? Just click "I'm New" - no need to sign up for an account. We have 3 free sessions in Hydraulics, and 1 in Electrical. We think that a handful of free sessions should be enough for people to decide whether they'd like to buy more, or just stick with our free TH-cam videos.
I register a long time ago, like 3months ago..I fully agree that somethings/subjects cannot be teached for FREE as they already exist firms which are asking thousands of dollars for a 3-4 day course to learn hydraulics..my personal opinion as expressed before it was that basic hydraulic should be ALL for free then raise the price of it when you start to learn about intermediate/expert "mode" of them..Aniway I will still following you guys because you are great.Nobody its perfect :-)!
Good to know you registered - we will be sending out invitations later this week. In the mean time, do try out the 4 free sessions. As we add content throughout the year, we'll definitely be releasing more for free. Our big challenge right now is making back what it cost us to build the site (which has been in the works for almost 8 years now, if you can believe it), and what it costs us to make the free videos every week. So we do need to do as much as we can to encourage people to pay. Our overall goal is to make great content, but it's pretty expensive to do (as I'm sure you can imagine). I really appreciate your feedback - cheers!
what is the name of this software, very very helpful, can anyone suggest me a similar software for educational purpose.
Thanks
Any one guide me regarding Rexroth A4VSO variable piston pump repair with new carriage kit piston shoe and cylinder pump has been generate the pressure as per require but not sustain properly on machine running
Could you please make a video on VDOP pressure regulation, let's take pressure regulation is 4.5 bar at the outlet of the pump.
Very good. Is there a Portuguese version?
What software was this designed in
why odd number of piston is used in hydraulic pump? Like 7 or 9.
65 lmp pump how many hp two motor run
How about high temperature oil if pump running to system ?
we have cat206 bft 1994 model hydurlic is slow but engine has overload
Sir please make a video EDC pressure control please sir 🙏🙏
I AM ABOUT TO DEVELOP A 30 TON SERVOHYDRAULIC TESTING MACHINE, AND I HAVE SELECTED A 30 HP MOTOR AND 37 CM3/REV YUKEN PISTON PUMP.
I AM CONFUSED WHETHER I SHOULD SELECT RADIAL OR AXIAL PISTON PUMP?
CAN ANYONE HELP ME OUT?
IF I HAVE TO SELECT AXIAL PISTON PUMP THEN I AM CONFUSED BETWEEN
1) PRESSURE COMPENSATOR TYPE
2) CONSTANT POWER CONTROL TYPE
3) LOAD SENSING TYPE..
KINDLY PLEASE HELP
why my hydrolik pump is very hot on the tank line?in the picture video port D reservoir tank.
Port D is the case drain line. When this line is running unusually hot, it often means that the pump pressure compensator setting has been adjusted above the setting of the system pressure relief valve. Please check that the system relief valve is set to the correct pressure, and pump pressure compensator too, as indicated by the machine manufacturer. Follow safe procedures, or acquire the services of a trained hydraulics technician to make these adjustments.
LunchBox Sessions what is the function of the valve compensator and how to set this,should be equal to the relief valve system or higher than the pressure relief valve system?my pump rexroth a10v140dflr/3
How many achieve pressure it can be?
I believe it depends on the manufacture of the pump model
Hello, love your all your videos, I'm trying to understand prime mover rotation. It may sound simple of a question, but can't find the information anywhere. I have a Vickers PVH980-L... that has to hook up to a diesel motor. The manual state's "Shaft rotation, viewed at
prime mover end: counterclockwise". Does that mean the output of the motor is counterclockwise or the input of the pump?
Input of the pump
Good
PRESSURE COMPENSATOR MUST BE SET WHEN THE PUMP IS RUNNING AND NO SYSTEM FLOW IS OCCURRING?
WHAT DOES NO SYSTEM FLOW OCCUR MEAN?
Mech E no system flow occurs when all directional valves are closed or when all flow valves are closed. When there is no consumption path for the pump’s flow, then the maximum pressure (compensator) can be set/adjusted. I hope that helps.
YES I GOT IT.
Can you give me Name and model of the oil pump to the same specifications and Hee be small ... please
the pump name should be a Bosch-rexroth and the model is just a pressure compensator one..
Thank
Your caption covered the pict
Good video but not too deep. I'm not sure if pump is Bosch Rexroth but one of my favorite the A10V or A10VSO doesn't look like this. The awash plate bias springs of Rexroth A10V series is parallel in the opposite side.
Most variable pumps have extra functions that could optimally operate systems like maximum and minimum mechanical flow limiter.
To adjust the settings of any variable pumps it's still advisable to use a suitable Relief valve.
I will never have any hydraulic system without any Relief valve.
Damn I wasted more than 10 years of studying deeply and experience in hydraulics.
The A10VSO is one of my favorites too. Would you believe that size 10 (smallest) of the A10VSO does look like this with the bias spring (without a piston) in direct opposition to the control piston? I could send photos of the pump disassembled on our workbench. But I do know what you mean. The size 18 and up are as you say, with bias spring/piston assembly in parallel to and on the other side of case from, the main control piston. We try not to over-complicate any one video - build up the learning in little chunks.
I agree re: relief valve. I see lots of piston pumps with and without min or max flow limit screw. Can go either way.
We have the A10VSO series in 3D with fly throughs and narrated video. With DR and DFR. Please do stand by :-)
I didn't understand what you meant about the wasted 10 years....
Keep on learning, - Carl
Oh no... the piston is symmetrical on both sides... it will not lift up. It has to be a "piston" with the spring pushing it down, instead of this double sided valve...
يا ريت يكون الفيديو مصحوب بالترجمه للعربيه
i am in.
My hydraulics pump flow and overload engine System slow
Thanks for writing. I understand that you are having a hydraulic system issue. Can you provide more specifics? Is there an issue with engine stall caused by excessive hydraulic pressure? Please be very careful with any pressure setting or pump control adjustments.
Come on guys. You always need a relief on a pressure comp system.
algo en español sobre hidrostatica
You can have pressure and no flow. And you can have flow and no pressure
Please subtitle all videos in Korean.
Please upload in Telugu language sir...
Tinha de ser traduzido por portugues brasileiro
Please make videos in Spanish?
You can probably skip 50% of the lesser-importance facts in a vid like this - you aren't speaking to completely braindead people, and if you were it would hurt them to watch it twice.
Usenge saaa