Hydraulic power pack

[Ryanjax]

Has anyone ever built a hydraulic power pack using an electric motor. I'm looking to build a press using a 5" x 16" stroke cylinder dual action. I'd like to use a 2 stage log splitter pump. My question is I don't know how to size the pump and electric motor. I think around a 5-7 sec cycle time would be about what I want. I also need to press at about 20 tons.

Any help on building one of these? I'm new to the hydraulic realm.

 

[spy604]

5" Bore X 16" stroke
piston ares = 5^2*pi/4 = 19.63 in^2
19.63 * 1500psi? = 29445lbf = 14.7 Ton
19.63 in^2 x 16" stroke = 314.16 in^3 displacement
314.16 / 5 sec = 62.8 in^3/sec flow rate = 16.16 gpm
HP = 1500psi? *16.16/1714 = 14 HP

 

[Ryanjax]

There seems to be different ratings for Gas engines and electric motors. If I'm going to need a 10hp motor I'm going to have to rethink my plans. I'd like to get by with a 5HP motor. Surplus center has a 13gpm 2 stage pump that it says needs a 6.5hp gas engine.

 

[spy604]

well its all a question of cycle time, thats where the horsepower comes into play. In reality it wont be stroking the full tonnage, so that reduces the HP. Also, if you wanted to use an electric motor, most industrial motor can be overloaded 200% for short periods.

 

[Ryanjax]

well its all a question of cycle time, thats where the horsepower comes into play. In reality it wont be stroking the full tonnage, so that reduces the HP. Also, if you wanted to use an electric motor, most industrial motor can be overloaded 200% for short periods.

So I should be good with the 13gpm pump with a 5HP motor?

I'm putting together a mental list in my head:

Pump
Motor
Tank
Filter
Regulator (I'd like to control the pressure down to 500psi. Can I have a high pressure loop and an low pressure loop and just isolate one or the other?)

Check valve
Control lever (still need to figure out which one)

 

[spy604]

I would add a relief valve valve too. For a control valve, a 3 position valve would be best, closed center. Meaning that the lever 'home' position is in the middle, which is closed. Why 500psi and 2 loops?

 

[stingry]

Unless you need the fast ram speed, look into an air over hydraulic system. Much simpler and compact. You can use an air/hydraulic jack and make a very effective press. My press is a 30 ton model and uses an air/hydraulic pump with a separate ram. The only drawback that I can think of is the slow ram speed.

Cheers
Steve

 

[Ryanjax]

I would add a relief valve valve too. For a control valve, a 3 position valve would be best, closed center. Meaning that the lever 'home' position is in the middle, which is closed. Why 500psi and 2 loops?

The press will be used in pyrotechnics and there are certain compositions that need lower pressures and others that require higher pressures.

 

[Ryanjax]

Unless you need the fast ram speed, look into an air over hydraulic system. Much simpler and compact. You can use an air/hydraulic jack and make a very effective press. My press is a 30 ton model and uses an air/hydraulic pump with a separate ram. The only drawback that I can think of is the slow ram speed.

Cheers
Steve

Right now I'm using a 10 ton air/hyd jack. It works, but the cycle speed is very slow. For pressing hundreds of comets it takes quite some time, hence the need for the hydraulic system.

 

[spy604]

The press will be used in pyrotechnics and there are certain compositions that need lower pressures and others that require higher pressures.

Then you just need 2 regulators and 2 relief valves. No need for 2 separate loops, both return lines just dump to tank.