Re: Adding pump to manual press - options?
''For 3 GPM at 5000 PSI I need a 10 Hp electric motor. Travel would be 0.6 in/sec''.
That specification is both correct and incorrect. It is correct for load lifting applications but not for pressing applications. The pump performance curve charts are not calibrated for normal pressing applications. For lifting a load you need constant pressure over a long distance, think forklift.
But in pressing applications, you only need to build enough pressure to move the cylinder against the internal friction of the cylinder until the ram contacts the work. Very little pressure is required. Then in the last fraction of an inch, you need to build pressure to do the pressing work, normally at a much lower speed. The HP required for pressing applications is a fraction of what is required for load lifting applications.
The problem with the charts is that they are presented in required HP, but that is not the parameter that should be used in pressing applications. The real parameter is the required torque to drive the pump to achieve the desired pressure without regard to the RPM of the pump shaft. (We're going to ignore internal pump leakage for the moment)
So how do you get the relatively high speed ram positioning combined with low speed high pressure for the actual pressing work? You use a two stage pump.
A quick search on Amazon turns up this 750W (1 HP) unit.
https://www.amazon.com/BestEquip-Electric-Hydraulic-Single-Solenoid/dp/B06XSZ6N66/ref=sr_1_45?keywords=Hydraulic+Pump+for+Log+Splitt er&qid=1649176777&sr=8-45
According to the specs, it seems to have a two stage pump, 5 LPM for low pressure, and 0.9 LPM for the high pressure range. Given the source, I would take the specs with a grain of salt. But it says it's rated at 10,000 PSI. You should be able to adjust the pressure relief valve to max out at 5000 PSI.
EDIT: I just noticed that the motor RPM is rated at 1400, this would indicate the specs were generated at 50 Hz, running at 60Hz, the low pressure performance would be a bit better than indicated.
Jim Dawson
Sandy, Oregon, USA