How much log splitter can a 5hp electric motor drive?

[user 140828]

I shouldn't have snarked. Just don't see how those numbers work.

 

[Mustang71]

Wood splitters direct has all sorts of electric hydrualic wood splitters. A 20 ton is 2000$. Says it has a 2hp motor.

 

[blades]

last double box beam I made was 2 schedule 40 ( roughly 1/4" thick walls) 4x8 ( maybe it was 6") tubes. slapped a 3/8" x" 8" wear plate on top, some angle iron on the sides for the slider guides ( other ways to do that) wedge is welded to beam through 3/8 plate tubes are welded together all the way around. plate is welded on sides and plug welded down the middle, have not twisted it or bent it yet, apx 30ton splitter. The HF for tig on my Dial Arc 250 went south so I ordered one of the chicom tig,mig,stick boxes last week. Inverter type 200 amp . electric meter won't spin so fast with that.

 

[user 140828]

Thanks, that tells me a lot! When you say plug welded, what does that mean exactly in your case? I've wondered how an added top plate does if it's only welded on the two edges. Having trouble picturing how the slider guides look--do you have a picture that shows them?

 

[Streblerm]

Plug weld=drill a hole through one of the overlapping surfaces and fill with weld to join to the two parts.

 

[blades]

plug weld - hole drill through 3/8 plate small rod into hole and nail it down , i back filled them afterwards. just angle iron stitch welded to the out side - not the best pic little fuzzy think i used 1" x 1/8" thick . in the lower right hand corner you can just see the end of the oil expansion/breather tank i made to resolve another issue- the return line is mounted fairly high ( blocked by eng,) on the side of that orange tank - same height as the fill port on the other side. that led to air being mixed in the oil as it was being returned at the top of the oil in the tank. if you filled the tank past that point to negate that effect when it got hot the expansion of the oil would just puke it all over out the filler tube and cap. Now the tank is completely full so no more air mix - worked out perfectly. if the guide rails get twisted up they are easy to replace. If I ever get around to it I would make the push plate twice as high and twice as long, big rounds put a lot pressure on the top of the push plate trying to twist up and off. making the slide longer and the plate taller would reduce that tendency or at least spread the forces out . to date I have not had any issues and there have been 4 ft rounds on it. it is a thin wedge so it slices first before contacting the spreader tube to the rear of the wedge. Had a round litterly explode on me a couple summers back got hit square in the chest which knocked me over plus getting my feet tangled up and went down on a pile fresh splits- dislocated shoulder ( again) and collected a whole lot of new oozing ports on my backside, which were not oem. trials and tribulations. this was a HF 30t splitter from apx 2002. still running the oem eng ( brigs) cylinder, pump and coupler . The valve in the pick is a new replacement , wore the oem one out. One of these days I would like to rebuild the lower half with a torsion axle or stubs just so you could pull it behind vehicle in town with out it trying get in front of you. Typical of most box store units. and a lot of the others as well.

 

[user 140828]

I see on the tank, nice fix. Be making my own tank so I'll need to get all that right too. Amazing to me that the little angle iron hasn't been ripped off by a stray twist, that part must be very well implemented. Four foot rounds, holycowbatman! You have a magic wand or something to get them up there?

About how many plug welds did you do down the length of the beam?

 

[blades]

Magic wand - tractor with bucket. welds - don't remember likely more than I needed

 

[Johnny Yooper]

Okay, so I was hoping to build a (honest) 20-ton log splitter powered by an (honest) 5hp electric motor.

So I played around with the oft-recommended calculators on surpluscenter.com, and according to these calculators ("Calculated for electric motors. Double this figure for gas engines.") a 5hp electric motor can produce 3gpm at 2550 psi without exceeding its rated output.

Happily, the calculators tell me that at that pressure a 4.5" cylinder will produce just over 20 tons of force.

Looking at the two-stage log splitter pumps offered on surpluscenter.com, I found that their 9-12446 MTE 13gpm pump has a high pressure stage flow of 3gpm.

So I could use a good 5hp electric motor, that 13gpm MTE pump, and a 4.5" cylinder to get reasonably fast log splitting up to 20 tons. Voila, right?

Then I called product support at surpluscenter.com to confirm my thinking, and happened to mention I intended to use a 5hp electric motor to run the 13gpm pump. The conversation went something like this:

Support Guy: "5hp isn't enough. You need at least 6.5hp*."

Me: "But I used your calculators."

Support Guy: "They're just estimates."

*(To my knowledge, a 6.5hp electric motor, if it exists, would be exceedingly rare. So, 7.5hp.)

So, hmm, is it kinda like Pirates of the Caribbean, "They're more like guidelines?"

Don't get me wrong, he may be absolutely right and it may be that I can't get 20 tons out of that setup. The problem is trying to find out for sure. A good motor will be my largest single expense in building a log splitter so I surely don't want to get it wrong.

I've spent hours searching forums trying to find out. While there is some discussion of electric splitters here and there over the years, it is rarely (in what I could find, anyway) accompanied by complete descriptions of working setups. Someone will say they or their cousin has been happily using an electric for years and it does everything they need and they may mention some details, but not their whole setup--actual motor type, pump size and hi/lo flow numbers, cylinder size, etc. Or they do provide some numbers which disagree with both the calculators and the support guy, and even I am skeptical.

Not sure where to go from here. I would appreciate thoughts and suggestions but would particularly welcome hard facts based on experience.

Which is what I thought I was getting from the calculators.

A couple of years ago, I converted my gas splitter to electric; I posted the details on here back then and I suppose one could do some searching to find it, but I'll give a quick summary here: electric motor is a Leeson, rated 230 volts, somewhere around 3500 RPM and around 22 or 23 full load amps, I think it's nameplated as 5hp. It's turning an 11 GPM pump rated for 3600 RPM; cylinder is about 5 inches OD. I have a pressure gauge at the output of the pump, the maximum reading I get is about 27oo psi, and that's when I deadhead the cylinder. I calculated between 17 and 18 tons for my setup. I was curious to know what the motor ampere draw was when splitting so I did some experimenting with various woods, I had some elm on hand which ended up being worse case but even then the motor never drew more than 9.5 amps when splitting that, and the pressure would spike at 1100 psi for a second or two and then drop down as the chunks went through the splitter. What all this tells me is that under any splitting condition, the motor never draws more than 1/2 load, so plenty of overkill in my setup. I also calculated the electricity cost and comparing it to gasoline was pretty much a wash.....as someone on here already mentioned, these machines by nature have a duty cycle with a good portion of the time they are running at no load (well, except for turning the pump....I forget what that amp draw is, but with a 23 FLA motor, it might as well be no load). Anyway, the best part is that I can listen to ACDC while splitting!

 

[user 140828]

That is super informative! Very helpful, thanks so much. I looked up your earlier post, too.

 

[Streblerm]

That 5hp motor is looking better and better.

 

[Bobby Kirbos]

This goes back maybe 15+years, but somewhere I read that to keep an average sized car moving at 55mph on a flat and level road requires only about 5hp. It's GETTING to 55mph that requires more power. I would bet that a similar principle applies to this application.

If the price difference between the 5hp and the 7.5hp motor is within the cost of dinner out with the wife AND the 2 are dimensionally the same, I would go for the 7.5hp motor. You still need Xhp to do the job, and the motor will only pull the current needed to do Xhp. Not only does the 7.5hp give you more reserve power (+50% over the 5hp), but Xhp becomes a smaller percentage of the motor's available power which means that the motor will not be working as hard (think 14" bar on 30cc vs 70cc) and will run cooler. Heat kills machines.

 

[user 140828]

Yup, I did go for the 7hp motor and it's being delivered today. I will probably run a 16gpm pump and 4.5" cylinder with it. If 5hp can push 11gpm, 7.5hp should be able to push 16.