We have a 20ton hydraulic press. It is driven by a hand pump. I'm using it has a simple press brake. I would like to replace the hand pump with an electric one. Firstly what does the 20ton mean ? What's the likely line pressure ?
I would want the speed to be low as not to loose too many fingers. I only need about 12 ton to fold the 4mm thick by 150mm long 90 degree bend. Any thoughts, advice or links ?

20 Tons means someone used the Bore Diameter of the Cylinders on the press and applied enough pressure to the cylinders area to get a force of 40,000#. You would need to install a pressure gauge in the hydraulic line to the cylinders and check pressure when the press is at maximum tonnage. Maximum tonnage is probably noticeable since the pressure will stop increasing after stroking the Hand Pump with the cylinders stopped by the platen.

Line pressure will like;y be between 1,500-3,000 PSI. However some Enerpac and Owatona presses operate at 10,000 PSI. The higher the pressure the smaller the cylinders.

Contact a salesman at the local Fluid Power distributor and ask for help. Another source could be the local Tech School's hydraulic instructor who could use your project as a teaching tool.

Hi,I recently installed an Enerpac unit PUJ-1401B- (120v)on a similar project. It works great and is variable speed if you like. Powered up and down if needed or power down and rod will retract by itself by the manual handle. Be sure to install the outfeed line gauge- that way you will have some kind of reference point. Should work just fine for your application. Brett