hydraulic press motor and other stuff

That’s a 3 phase motor.
 
I would advise to not use a vfd. I started with a 10hp vfd running my 10hp press and It would keep tripping out the vfd. If you had like a 7.5hp vfd on a 5hp motor maybe. But once I switched to a phase converter I was shocked how much more power I had put if the motor. I would just pony up the cash and get a plug in 240v 5hp motor and do it corect. Or build a rotary phase converter to convert 240v single phase into 3 phase like I did.
 
If you have a problem finding a suitable motor let me know. I am a motor horder. This is My little stash, i go though them and replace the bearings and clean them up. That baldor is nice, but I’m quite partial to them. My next Favort is Toshiba, I think thy make a dang fine motor. My 25hp motor is a Toshiba. But onto your pump. My math says that’s good. 5hp will run at a max of .46in^3/rev at 2500psi and 1.35in^3/rev at 850psi. This is at the 1725rpm. With a 4.5” cylinder you get 19.88 tons and a ram travel speed of 2.20”/sec in low pressure and .75”/sec in high pressure. Retract is a tad faster at .93”/sec and 2.74”/sec. this is assuming a 90% efficiency of the pump. After building it you could possibility bump the pressure up and eek a tad more HP out of the press. But have to be carful that you don’t slow the motor down to much or you end up loosing speed. I will post a screen shot of my calculations.

Here is a little motor eye candy for yeah. Funny thing is that big blue motor is a 7.5hp baldor and the big green on to the right of it is a 15hp baldor. The rest are 3hp and 5hp. And like I said I have a 25hp as a phase converter for the 10hp on my press. My wife says I’m a motor whore. Or maybe she said horder. Maybe I should have my hearing checked

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This is my 25hp baby in the back of the truck. And my wife walking away shaking her head when I said “just a sec I need to take its picture”.
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found a single phase motor 5hp, 1800rpm TEFC. So with the .44ci 22gpm pump, and a 5"x8x2 cylinder, instead of the 4.5, it would loose a little speed if i understand all that you are trying to teach me right?
 
At .44ci displacement, 1800 RPM will move a 5" cylinder .672 inches per second in extension.

At 2500 PSI it will require 5HP on the nose to maintain that speed.

2500 PSI in a 5" cylinder generates 24 tons in extension.

This is just a tit faster with a bit more tonnage than my press. The difference being you're simply using all 5hp of the motor, and I'm using 4.79hp. Side by side I don't know if you'd actually be able to tell the difference. Other than yours running quieter.
 
JTknives said:
Shush, I told my wife my big press build was necessary. If I was doing the build around a 5hp motor this is how I would do it.

Motor = 5hp, 1745rpm
Cylinder = 4.5” bore, 2” ram
Pump = 2500psi @ .45 in^3/rev

This gives you .75”/sec down and .93”/sec up. This setup puts out 19.88 tons. Remember pumps are not 100% efferent so with a good pump your getting around 90% of the fluid it says. Also it’s worth getting a good quality motor bevaus there is allways a little extra HP hiding in there. For exzample I did the math for my 10hp at 2500psi And after it was built I slowly bumped the pressure up to see what the motor could actually handle. I’m now sitting at 3000psi and my motor does not mind. But if I did the calculation for 3,000psi at the beginning then I would be stuck with a lower volume pump and could not get that extra umph out of the motor. Also the lower speed motor is sure nice for the lower noise. It would be a toss up weather to go 2 stage or single stage. I think 5hp is on the edge of being worth it to go single stage. You won’t be dazzled by blazing fast speed but you also won’t have the delay in switching from low to high pressure. Plus I think (don’t really know) single stage pumps are build better and more efficient. Here is a screen shot of how I came up with your numbers

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Click to expand...
Can I get this excel? Also why and nobody going past the 20 ton range?
 
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