Sorry, you said you had a two stage pump already, what is the displacement of the second stage? It will still build pressure at half the speed... just curious if your motor can pull it. Depends on system pressure and pump displacement.
Yes a 2 stage hydraulic pump motor . I was assuming 85% pump effenciency so on low pressure/ high gpm would be around that 11-12 mark and on high pressure/low gpm would be around that 3 gpm mark. Not considering electric motor efficiency and slight rpm drop under load. This is assuming a 28 gpm pump ( 21gpm low pressure and 7 gpm high) run at 1750 rpm. Probably run around that 2500 psi. How big a pump are you running with your 2hp low rpm motor. I could go down to a 22gpm pump but would still want around that 9 second cycle time
Don't have a pump yet. Just wondering if this set up would work. I have the motor only now and the splitter. 3 .5" od cylinder x 24" stroke. Rod is at least an inch or bit more.
I'm not the original poster... Just thought I could possibly help you with the hydraulics... sorry for the confusion. But with 2 hp motor, and at 2500 psi, a 0.15 cubic inch per revolution pump running at 1750 would be about as large as you could go. I put something like this together at work for a press... but I don't remember what size motor I had. Your cycle time is going to depend on your cylinder size and how long you are in the first or second displacement of your pump.
Your tonnage is only going to be around 14t with a 3.5" cylinder bore and that's only if you are pushing 3000psi... More like 10.5t with a 3" cylinder bore at 3000 psi. Just make sure all your hydraulic components are rated for your maximum system pressure.
I have a 5hp TEFC 23amp 1750 rpm motor. Specs on 2 stage pump are low pressure 1.385 cu in/rev and high pressure .465 cu in/ rev. @ max 3600 rpm 3000 psi. . My motor will be turning that pump at 1/2 that speed so values should be 1/2 that. Then figure in probably a 85% efficiency just for pump. Motor rpm will drop some too under load. Also can drop drop down to 2500 psi so should be safe at that rating? 3.5" od x 24" cylinder and 1" ram. I already have that motor and lots of experience with motors on my farm. The slower rpm motors seem to last alot longer and can be rewound and are about 2x +heavier than the high speed compressor open drip motor I looked at . Plus less noise, wear and tear on pump and hopefully less heat too. Thanks for piping in. Never hurts to hear others thoughts.
hi presssure is .465 cu in/rev , low is 1.385cu in/rev. Thats at 3600rpm 3000 psi. I'm driving at 1/2 speed plus figure on only 85% pump efficiency then will be some rpm drop on motor under load and motor efficiency % should get me down to that 5 hp required according to some charts i looked at. This is my thinking but I could be wrong.
I plan to run it 1/2 speed with the 1750 rpm motor
A standard two stage 28gpm pump is going to drop down to low vol (4-6gpm at 3600, or 2-3 at 1800) above ~600 psi. A 5hp 1750 electric motor should have no,problem driving that pump. As long as you realize best case is 8-10 second cycle time, not the 4-5 secs a 28gpm pump and 4” cylinder usually delivers.
Thats what i was hoping for. my cylinder is only 3 or 3.5" not 4" so that may speed it up a bit. I already had this motor and am hoping the pump doesn't produce that high pitched whine the 3600 rpm pumps do. Plus nite and day difference in motor quality compared to the OD compressor ones ( even the 23 amp versions)
Got it put together and works mint. My cylinder is only 3" bore so cycle time is under 8 seconds. Because it splits in both directions I can split alot of wood in a short period of time. I went with bigger 3/4 " hoses everywhere except from the splitter valve to the cylinder (1/2"). I can go bigger here as ports are 3/4" as well but haven"t yet. With the slower 1750 rpm motor driving the 28gpm pump oil just feels warm to the touch and you don't have that annoying high pitch sound the high rpm pumps put out. Only the hum of the motor is all I hear. Being only a 3" bore was a little concerned about tonnage but has split anything so far .That being said all I have split so far is ash. Pump rarely goes into 2nd stage. I think the shape and thickness of the wedge makes a big difference. Its a SPLITFIRE 2 way splitter made here in Ontrio Canada. Its rated as 18 tonne when run off tractor hydraulics so am thinking it should be putting out the same when run off the 5 hp motor.
