# DIY log splitter with electric motor



## gmarblestone (Nov 15, 2011)

I have an electric 2hp motor lying around and i am thinking of building a hydraulic log splitter using it.
I can weld just fine and have some overall mechanical skills but i am wondering how the pump secures to the shaft of the electric motor.

Anyone done such a thing or have ideas on where to get parts?

Thanks,

Grant


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## Somesawguy (Nov 15, 2011)

Most people use a lovejoy. 2HP will be pretty slow or limited, but best of luck with your project.


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## gmarblestone (Nov 15, 2011)

Well 2hp electric is comparable to a 4hp gas right?

Wel-Bilt Electric Log Splitter  5-Ton, Model# 65562WB | Log Splitters | Northern Tool + Equipment might be the way to go anyway. it is pretty cheap.
The parts i see would almost make it the same price to do it myself.

G




Somesawguy said:


> Most people use a lovejoy. 2HP will be pretty slow or limited, but best of luck with your project.


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## Whitespider (Nov 15, 2011)

gmarblestone said:


> *Well 2hp electric is comparable to a 4hp gas right?*



NO! That is not right.
Horsepower is determined by the same calculation whether the motor is electric or gas powered.
HP *=* (Torque *X* RPM) */* 5250
- - OR - -
Torque *=* (HP *X* 5250) */* RPM

Most gas engines run at 3600 RPM, and most electric motors run at 1750 RPM. It takes a minimum amount of torque to run a splitter pump… but the pump also needs to run at rated RPM before it can make full fluid flow and pressure. Let’s say our splitter pump requires a minimum of 5¾ Ft-lbs of torque and 3200 RPM to achieve full pressure and flow, and rated for a maximum 3600 RPM.

So a 4 HP gas engines running at 3600 RPM produces 5.83 Ft-lbs of torque.
And a 2 HP electric motor running at 1750 RPM produces 6 Ft-lbs of torque.
Both power supplies have the same torque, but the electric motor runs way too slow to run the pump efficiently… the ram would move at only half the speed and with a lot less power under load. If we move to a 2 HP electric motor running at the needed 3200 RPM we end up with only 3.28 Ft-lbs of torque… the motor will stall and burn-up under load.

Now you could use the 2 HP electric motor with a different style pump… one that makes full pressure at 1750 RPM… but to keep the torque requirement in the 5¾ Ft-lbs range it would be painfully slow… but that’s another lesson in mechanical dynamics.

Yes, a 2 HP electric motor will do the same amount of work as a 4 HP gas engine… but only load being driven isn’t RPM dependent. For example, if your portable grain elevator requires a minimum 2 HP electric motor (at 1750 RPM, or 5¾ Ft-lbs of torque) it would require a minimum 4 HP gas engine to run it. But, the gas engine would run it twice as fast.


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## pdhowell (Nov 16, 2011)

Well, maybe, but my 2 hp, 1750 rpm electric powered splitter works pretty well. What you say is true about the torque but the splitter mechanicals do not develop half power of the hydraulic pump at the lower rpm, it pumps (in theory) at half the 3600 pump capacity. The pump pressure is what is set as the bypass pressure. With this reduced flow on a splitter with a 18 inch ram, 3.5 inch cylinder the cycle time is 14 seconds. My stove only takes 18 inch wood, so longer cylinder travel is just wasted time and a larger, heavier, harder to move beam.

With 3500 psi hoses on my splitter, I run the bypass pressure at 3000 psi. The splitter is something like a true 28,000 psi splitter, better than a four inch cylinder run at the typical 2250 psi. On 18 inch wood, it splits everything, literally at the flick of a switch. You do need 230 volt service, an extension cord, or a generator. Out in the woods, I bring the generator and have lights to work at night when, because when I get home, it is often dark.

There several advantages to the 1750 rpm motor. There is no cavitation caused by the high speed gear pump and there is far less internal friction of the oil, resulting in no (or minimum) heating of the hydraulic oil. That heat is wasted power. I have seen splitters that you cannot put your hand on because they are so hot. The pump whine of a 1750 rpm drive pump is acceptable, and you can talk, listen to the radio, split in an enclosed shed, etc. The one 3450 rpm electric splitter I have seen would have me looking for ear plugs and working outside. I cannot help but think that the engine to pump coupler will last longer.


When I build my next splitter for my son, my third, it will have a 1750 rpm motor, 230 volt, no more than 30 amp draw so that you can use it off a drier outlet. We will be using it in a barn.

Hopefully useful


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## TN_WOOD (Nov 16, 2011)

Seems the electric splitters that I've seen have some sort of screw shaft. Sorta like a garage door opener. The motor turns the screw and that screw moves the wedge.

Sears/Craftsman used to sell one. They might have parts

I've seen some open box/scratch n dent ones at some of the stores. Northern Tool sends coupons and often has some remanufactured stuff. I like projects, but something tells me unless you have a big stockpile of scrap metal, it's still going to cost more than what you can pick one up for in the stores. 

Build a big fan with that motor.


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## kubotakid (Nov 18, 2011)

*Gas verses elec*

I think youll get quite a few different opinions on gas engine hp ratings verses elec motor, I for one dont think they are equal, I have 2 emglo portable air compressors 1 has a 5.5 hp honda, the other has a 1.5 hp electric motor, that spins @ 3650 rpm, orignal equipment, acroding to the factory specs they put out the same amount of air, jess sayin,... another comparison that comes to mind is the ingersoll rand T30 compressor, comes with either a 5 hp elec, or the 14 hp kohler gas, I remember hearing more than once that the rule of thumb was a 3 to 1 ratio, and from what Iam seein, its pretty close, Iam gona go with,..i dunno :msp_unsure: Eric


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## wiseangler55 (Feb 17, 2012)

kubotakid said:


> I think youll get quite a few different opinions on gas engine hp ratings verses elec motor, I for one dont think they are equal, I have 2 emglo portable air compressors 1 has a 5.5 hp honda, the other has a 1.5 hp electric motor, that spins @ 3650 rpm, orignal equipment, acroding to the factory specs they put out the same amount of air, jess sayin,... another comparison that comes to mind is the ingersoll rand T30 compressor, comes with either a 5 hp elec, or the 14 hp kohler gas, I remember hearing more than once that the rule of thumb was a 3 to 1 ratio, and from what Iam seein, its pretty close, Iam gona go with,..i dunno :msp_unsure: Eric



i agree 100% percent,i have a 5 hp 3600 rpm electric motor on my homemade log splitter with 16 gpm pump.its ran fine for 2 years so far.math does'nt lie, but their is a lot of variables that need to be figured in.i have read a lot on this subject,i/c engines are only 35% efficent wheras e-motor is 85%,plus the torque curve is different.in real life situations 2.5 to 1 is about right.


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## CRThomas (Feb 19, 2012)

*Electric splitter*



gmarblestone said:


> I have an electric 2hp motor lying around and i am thinking of building a hydraulic log splitter using it.
> I can weld just fine and have some overall mechanical skills but i am wondering how the pump secures to the shaft of the electric motor.
> 
> Anyone done such a thing or have ideas on where to get parts?
> ...


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## CRThomas (Feb 19, 2012)

*Samesawguy*



Somesawguy said:


> Most people use a lovejoy. 2HP will be pretty slow or limited, but best of luck with your project.


 It might cost more but the pleasure of building it I could have bought a electric splitter but as I split it's my project I built myself. I solved the heat and low win I put a foot peddle on mine. I don't split a hundred miles a hour. Satisfaction and profit.


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## cedarhollow (Nov 5, 2017)

You might try it with 2hp motor as long as you match pump with the motor. 3600 rpm electric motor has 1/2 the torque of same hp 1800 rpm motor. You might find that a 5hp 1800rpm motor would provide much better flow rate for a full size splitter. I'm not an expert but do enough hydraulic stuff to be dangerous. There are many machine tools, metal benders, iron workers and stuff like that that use 2hp but most are very short stroke applications


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## kevin j (Nov 6, 2017)

The torque and horsepower calculations are all the same for any form of power gas or electric.

The big differences is that for a gas engine there's only about a 10 to 15% rise from rated torque to stall torque as the gas motor slows down. On an electric motor the stall torque can be two or three times the rated torque so for short periods it can go really high on the torque although the motor would overheat and burn out if it ran continuously like that


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## alleyyooper (Nov 6, 2017)

Ever give thought to a belt with pulley drive? could also do a chain and sprack drive but then you wouldn't have the saftey slip.


. Al


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## CylinderService (Nov 13, 2017)

I agree with the above comments that Horsepower is Horsepower, regardless of the source. But also that electric motors have more power than equally rated small gas engines. The problem is that the small engines are sometimes wildly overrated. Electric motors are rated more honestly, because they're so often used for industrial applications. We usually consider the small engines to have half to two thirds of their claimed Hp.
We use 2 stage logsplitter pumps for our shop cylinder testing units, powered by a 1750 RPM elect. motor. We get 2800 PSI, and half the rated flow, which is for 3600 RPM. Gear pumps run at 500 RPM or more will generally put out their expected pressure and flow, calculated by displacement times RPM.
Logsplitter pumps are not good candidates for belt & pulley drive. They have small shafts, sometimes with grooves cut in them, and no bearings to support a side load. Just drive them with a Lovejoy coupling, and line it up carefully.
[email protected]


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## rarefish383 (Nov 13, 2017)

This post is 5 years old. I think that guy broke down and bought a Huskee, Joe.


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## Sawyer Rob (Nov 13, 2017)

I think electric motors are wildly over rated!

Ever see a 6hp vacuum?? How about a 4hp compressor that plugs into 120V?? OR the 3hp router that runs off 120V on a 20 amp breaker!! lol

I could go on and on, BUT all you really have to do with electric motors, is look at the "motor plate"...

On 120V it takes 10 amps to make 1 honest hp.., yes I know the paper 750 watts thing ect... BUT, I'm talking hp after all the loss' of friction ect...

2hp on 120V will pull 20 amps... On 240V is will pull 10amps, as it has two hot leads, 10 amps each...

My 5hp compressor pulls 26.5 amps on 240volts... That's a strong 5hp motor.

I've seen compressors called 5hp, that when you look at the motor plate, they only draw 15 amps on 240V, that's an "honest" 3hp...

SR


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## triptester (Nov 14, 2017)

I must agree that advertised product ratings are often overblown but electric motor name plate ratings are more accurate.


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## loadthestove (Nov 19, 2017)

I know this post is an old one but for what it's worth ,.I have an electric splitter that works great.
4 x 24 cylinder with 2 inch rod.Im using a 3 horsepower 220 volt electric running 3450. Two stage 12.5 gpm pump (I think).
Have 8-10 second cycle time unless it goes into second stage.

Rarely will it fail to split anything I put in it .


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