pump question?

[cosworth34677]

ok maybe a silly question but....
lets say if i had a hydraulic pump that is running off a 540 motor turning 17,000 rpm's. alet say it make 200psi what would happen if i put a race tuned motor like something making 30,000 rpms on it, would that make difference in output or power on the pump? or will it just heat up and break stuff?

[sparkycuda]

Basic hydraulic theory says that increasing pump speed changes the flow or quantity of fluid being delivered - in practice it makes the cylinder move faster. Pressure capability of the pump is determined by it's efficiency - the fit of the parts and type of pump - increasing pump speed does not change its efficiency. For each pump there is an engineered "sweet spot" where RPM and pressure gives the best performance without damaging anything. Refer to the pump specs. If the pump turns too fast, it can cavitate - push the oil out faster than it can supply oil from the tank - a very bad thing, as it damages the pump and possibly other components, and generates heat like a mutha! Again, refer to the pump specs and build the system according to the manufacturer's recommendations. Some tweaking is possible because most specs are conservative to increase pump life. Just have to be careful when doing so.

Ken

[cosworth34677]

ahh i see! so if you want more power out of a pump you have what do you do? or are you pretty much stuck with what you got?

i read that guys that put hydaulics on cars sometimes put bigger volume rams on to give more power . is that true

[sparkycuda]

More power out of the pump? Not too much you can do, depending on the type of pump - maybe tighten the tolerences but often not practical. However, if you want to lift more with the same pump, you can use larger diameter rams - but - as the diameter increases stroke speed slows because you have a larger volume cylinder to fill in the same amount of time. So it is a compromise among many things; required stroke speed, volume of pump, maximum pressure available from pump, physical constraints of cylinder dimensions (will it fit on the machine where you want it?), needed electric power to drive the pump, etc. If a slower cylinder speed is acceptable and a bigger cylinder will fit the machine, you can do more work (lift more) with a given size pump.

Ken

[cosworth34677]

the main thing is im about to take the hit and buy some hydraulics i for a company in spain thats sells stuff pretty cheap so thinking of get started there for my first hydraulic build. i want to convert my excavator the running on firgelli actuators to hydaulic rams. and don't want to go into this with out knowing anything about it.

so here my goal i wan to dig in a kind sandy dir patch in my back yard. its is out in the rain and weather so it gets packed down also i take my excavator to the park and dig out in the vollyball court there and thats all whit beach sand. i live in florida so there isn't much hard clay or ground around but the red clay hills behind the park. the pump i want to get makes 10 bars and i'll be happy with the thing digging in the sand all day without breaking .


so if i get bigger rams i can make more power at the bucket and stick? but tthe thing is you don't want to get something to big or you'll lose speed

[cdm]

Don't buy that pump/valves!

Valves are known to leak/have bad internal machining

and the pump has no pressure relief.

yes bigger ram bore = more power, but more fluid to move so depending on the pump capacity and your tubing size you might run into lack of speed.

[cosworth34677]

ok then whats a good pump and valves that are not going to break the bank? im kind of on a budget.

[cdm]

ok then whats a good pump and valves that are not going to break the bank? im kind of on a budget.

industry standard for diy and budget seems to be leimbach. its what i ended up going with.

http://www.leimbach-modellbau.de/

check my thread down below where i asked the same questions and more about 2 months ago.

http://www.rctruckandconstruction.com/showthread.php?t=5657