log splitter plans

[J_J]

I believe the electric motor of 5 HP is equivalent to a 10 HP engine driven pump. Maybe even less, some say 2 1/2 ratio.

[sizzami]

5" overkill? simple, remember big cylinder needs bigger pump its all relative I can, and have built one with a 6" cylinder faster than a 4" cylinder

[LD1]

The best way to figure electric motor size is with the formula

Flow(gpm) x PSI divided by 1714 x pump eficcency

For the 22gpm logsplitter pump you can figure it two ways, high pressure low flow or high flow low pressure.

the 22gpm is @ 650psi so

(22 x 650)/(1714 x 85% eff)=9.81 HP required.

a 16gpm pump requires 6HP and an 11gpm requires 3.5HP

I wouldn't use a 5HP electric on a 22gpm pump. You gould get by with one on a 16gpm pump because you won't be running full pressure continuously, and especially if you get one with a SF of 1.15. And make sure you get a TEFC motor to keep the dirt/dust out becuse woodsplitting is dirty.

If you are insist on a 22gpm then I would reccoend a 7.5HP minimum and perferabally a 10HP motor. The 22gpm pump is about $100 more than a 16 and the moter will run you at least that much more as opposed to a 5HP. The 16gpm 4.5" cyl will nearly identical cycle times as a 22/5 combo.

We have a 4.5/16 combo and have yet to stall it, even in 25" crotch peices of white elm that was still green. 5" is overkill...unless you plan on a 6 way wedge.

[LD1]

I also forgot to mention that electric is a lot cheaper to operate too. If you run a 5hp motor under max load for an hour, it will only use about 4kwh of juice. @.10 per kwh (which is a litter higher than what i pay) thats only 40 cents. with gas @ 2.60 right now, your gas splitter would have to be able to run for a full hour on only just a hair over a pint of gas. And most use about 1/2 gallon.

[J_J]

Something like this on a 24 in log

4 in cyl at 5 gpm = 1.5 ips = 16 sec

6 in cyl at 20 gpm = 2.7 ips = 8.8 sec

[bassgrinder]

Hey EdK,
Thanks for posting that link to the previous electric motor wood splitter discussions. Did end up using electric in your splitter? I see RonL was quite a bit into his project, at least having the hydraulics package for it done. That discussion from 2004 was very interesting, One great idea I saw was that with a electric motor / hydraulic pump unit powering your log splitter that simple QDs would yield a fairly portable package that could be used in ones shop for a variety of gadgets one might otherwise figure he could never afford to have in his shop, ie iron worker, pipe and tubing bender, porta-power, power press, shear, basically any thing that can powered with hydraulics, it can even be used to crimp hydraulic hose fittings!!! I also noticed some one posted this link up in that discussion http://www.green-trust.org/LogSplitter.pdf This tell of a conversion of a northern hydraulics splitter after calculating the equation to be 1=2.5 they replaced the 5 hp gas engine with a 2 hp electric motor and found the splitter had more available power with electric. They describe using this splitter in a “for profit fire wood business” so this is not a casual guess at performance. They also describe purposely running until it failed to split using a crosswise block and observed a mere 3 volt drop at the motor and no loss in rpm. This said, I believe that a 5 hp electric motor would more than be adequate for the 22 gpm pump. In fact I think if a 1.5 service factor was used, it would likely handle the 28 gpm pump.

[LD1]

The key is to check and see how many amps it is pulling, if it doesn't pull more than the nameplate says multiplied by the SF, when maxed out, then you are okay. (If nameplate says 20 amps and SF of 1.15, don't let it pull more than 23 amps or it will burn up prematurly)

As a general rule of thumb, 5 amps per HP if you are using 220. That would make a 5HP motor 25 amps.

From experience, I had a old air compressor motor that I wanted to use on a 11gpm logsplitter. It was rated at 15 amps with a SF of 1. It had enough power to run the splitter all the way up to 3000psi and didn't stall, but it was drawing 21 amps @ max. so we didn't use it. If a 11gmp pump will draw 21 amps, i can only assume that a 22gpm will draw around 40. If you put a 5 HP electric on @ 25 amps with a SF of 1.15, it will run the pump and split the wood, but you will be pulling about 10 too many amps everytime you get into a tough peice, and the lifespan of the motor will be reduced.

[Scotty370]

Boy, I just can't imagine going electric with the 'mobility limitations' that it brings with it! I'm running a 4"x24" ram w/ 2 stage 11gpm pump off a 5hp briggs! It's all two guys can handle getting the wood to it and away without bustin' butt. That 220v line is expensive when you want to split in the woods, or a neighbors. I really kinda like that rack/pinion video that J_J offered up. Unless your in 'commercial mode', keep it simple! Otherwise, go for that Bobcat Beast! Good Luck! Keep- us posted! ~Scotty
OOPS! Those Vids were posted in another thread! Help me out here J_J!

[LD1]

If mobility is not an issue, electric has about every advantage over gas.

Some have already been mentioned
Cheaper
Quieter
No fumes
Easier to start
Never have to stop to refill

And one of my favorite reasons, neighbors wont ask to borrow it

[Scotty370]

LD- Points well taken! But wait 'til they ask ya to help them move the stove for power? Claim you've only got a short cord, so splitting in the kitchen is their only option!