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Electric powered lag splitter

Discussion in 'Firewood, Heating and Wood Burning Equipment' started by homemade, May 30, 2017.

  1. homemade

    homemade Certified Chainsaw Tester

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    I have a splitter that was given to me. Needs a new pump, motor, hoses and oil... and I'm sure a bunch of other stuff. I have an 11gpm pump for it. I am thinking about putting a 220volt electric motor on it. What size electric motor do I need for said pump? I have about 15 amps 220v available from a generator for remote locations.

    Will a 3hp motor at 3600rpm fit the bill or be underpowered?


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  2. Yooper John

    Yooper John New Member

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    I recently removed the 6hp gas engine on my splitter and replaced it with a 5hp 220V 3600 RPM electric motor; I have an 11GPM two stage pump; so far it has split everything I put on it. If you don't get into very gnarly wood, I think you'll be fine. After a couple hours of steady splitting, the frame of my motor is barely lukewarm, so the motor is drawing way less than the 20 amps stamped on the nameplate. I do my splitting near the workshop and have easy access to 220 Volt outlets, plus I really like how quiet it is now. Nonetheless, I did modify the pump mounting bracket such that it bolts to both the electric motor and the 6hp gas engine, just in case something ever happened with the motor or if I want to take the splitter somewhere where there's no Edison, can make the swap in less than 10 minutes, so I wouldn't be down long, something to consider. Did the math to compare electricity cost vs gasoline for an 8 hour splitting spree and it was a wash, however that was based on the motor drawing full nameplate amps, which it isn't, so Edison is cheaper, just don't know how much; really don't care one way or the other; being able to listen to AC/DC while splitting is worth it:guitar:
     
  3. ValleyFirewood

    ValleyFirewood Addicted to ArboristSite

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    3hp is about it. Maybe 4hp if the gen set is good. 15amps, 240v is 4.8hp "in theory".
    Keep in mind in rush and stall draw will be WAY higher.

    My 4kw gen set won't run my welder other than the lowest setting, and even still it stalls it. It's rated at 21 amp draw at wide open... gen set 16 amps.

    All that doesn't address that an 11gpm setup will be laughably slow though.
    I'd suggest at least double that.
     
  4. NSMaple1

    NSMaple1 Addicted to ArboristSite

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    Can you check your draw with an amp meter (clamp on) to see how much it is drawing? Just curious.
     
  5. homemade

    homemade Certified Chainsaw Tester

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    Well here's what I've come up with thus far. For a leeson motor from surplus center is $450. The similar motor from harbor freight its only $150. Now for some more electric math. A 3000watt generator should be able to put out 13.63 amps at 220 volts. Now the motor I was looking at, a 3hp motor, will draw up to 15 amps. But that is at full draw. So the generator won't keep up at full draw. But that means the hydro pump is also working at full capacity. I could back the relief pressure down so the hydro pump doesn't have to work so hard, In turn, not drawing as much amps. The nice thing about electric motors, is that they only draw the electricity they need to get the job done while keeping rpm the same. While a gas engine has to be at full horsepower to make the rpm.

    Ok now for the work math. Work is force x distance. Or in order to get full capacity out of my 11gpm 2 stage pump, it needs 5 hp at 3600 rpm. If I open the relief valve, it will need less power at same rpm.

    I have a 5hp Honda motor from a junk pressure washer that I'm going to use in this setup. I do like the idea though of mounting the electric motor next to the gas and just pulling the pump off gas and putting it in electric for splitting around the house and putting it back on gas for in the back woods or friends house with no power access.


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  6. ValleyFirewood

    ValleyFirewood Addicted to ArboristSite

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    3kw is about 12.5 amps. It's 240v, not 220. A cheap gen set won't last long at full bore. I burned one up 2 years ago with it hooked to a battery charger (dead batteries on the excavator several miles from an outlet).

    If you expect to run a 3hp motor, I'd look at a a 5k or larger gen set.



    5hp on an 11gpm for a gas engine sounds about right. Electric would be less, 3ish sounds about right, though I'd research it.

    Are you planning to plug the splitter in to your house/shop? If not, why bother with a motor and gen set? Just put a gas engine on it.
     
  7. Johnny Yooper

    Johnny Yooper ArboristSite Operative

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    Yeah, I've been meaning to do that, will need to borrow one from work or buy one. No load amp value for this motor is 4.5, so just idling with the pump turning, I wouldn't expect the current to be more than 5 or 6 amps. I've been watching the pressure gauge while splitting and on the toughest pieces it will reach 1000 or 1200psi for a second or two, and then drop off as the piece goes through the wedge. I'll see if I can scrounge up a meter this weekend as I just finished cutting up and hauling home what was a 43 inch dia. silver maple so have a lot of splitting time coming up.
     
  8. juanni

    juanni ArboristSite Lurker

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    I built a electric log splitter.
    Used a 13gpm 2 stage pump and a 5hp 'special' compressor motor, 3450 rpm that I believe is closer to 4.5 hp.
    Anyway, more than enough power and speed for a 4" ram.
     
  9. Johnny Yooper

    Johnny Yooper ArboristSite Operative

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    Got my hands on a clamp-on ammeter today and did a little data collection; before I get to that, I'll provide the following info on motor draw vs load so y'all can see how the motor is loading under various conditions (I happen to have complete specs on this motor):

    no load: 4.5amps
    0.25 load: 7.0amps
    0.5 load: 10.85amps
    0.75 load: 15.5amps
    1.0 load: 20.53amps

    Motor is nameplated 230 volts, 5hp, 3450RPM, 20.8 full load amps (single phase cap start/cap run design).

    The data:
    motor idling, spinning pump only: 6.3 to 6.4 amps

    extend stroke: 7.0 amps; return stroke: 7.9 amps (reading taken within one minute of start up).
    After letting the motor operate for 5 minutes or so, current draw decreased a little (as expected): 6.6 amps on extend stroke and 7.4 amps on return stroke.

    I picked up a load of elm over the weekend, so I thought this would be the best species to test with: ran three test splits (see attached pic) and motor draw was 8 to 9 amps on the split stroke, with the highest recorded value of 9.4 amps and 1600psi to 1700 psi on the gauge on the toughest of the three splits, those values only lasted about one second and then decreased quickly, so I would almost call these spike values. I tried to stall the pump or motor by keeping the valve open when fully extended as well as fully retracted, only for a second or so just to get a reading on the ammeter.......could not get it to exceed 15 amps (2700psi on the gauge). So even under worse case conditions, this particular motor does not exceed 3/4 load.

    I had 240 volts to the motor per my measurement at the outlet, but that ain't going to skew things much for this experiment.
    GEDC2667.JPG
     
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  10. Ted Jenkins

    Ted Jenkins Firewood by TJ

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    This has given me a lot to consider. The last few years has been a bit of an ordeal for splitting. I often come to my commercial property with a 3/4 ton pickup with about 1 1/2 cords. Jump into another truck hook up to my splitter and return to split the wood and load it into one of the trucks and deliver it. Then before the day is done hook up the splitter and return it home. If an electric motor was used it might be quiet enough to split wood at my house. There is 60 amps at 220 or 240 volt single phase available at the bottom of my drive way. There is a 60 amp buzz box welder at the bottom of my driveway hooked to an extenstion cord from my shop. So a 10 or 12 HP motor might just do the trick. This is very interesting. This would also give an alternative option for processing.
     
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  11. NSMaple1

    NSMaple1 Addicted to ArboristSite

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    Lots of good info there for someone. Thanks!
     
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  12. Johnny Yooper

    Johnny Yooper ArboristSite Operative

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    The only noise I get is from the pump, and it isn't bad, you need to talk above normal voice to have a conversation, but it's a heckuva lot better than a gas engine; wish I would have made the conversion when the kids were little as the wife frowned upon me running machinery during nap time.....I could have split a lot more wood after work/evenings vs waiting for the weekends. Anyway, you must have a darn heavy extension cord running to that buzz box if you can pull 60 amps, so yeah, you shouldn't have any issue powering an electric motor around 7.5 - 10hp or so. After my experiment yesterday, I have a better idea of what the motor is drawing current-wise, so even if I guesstimate an average value of 8 amps running all day, that works out to less than $1.30 for eight hours of steady splitting, don't really care either way; simply was fun doing the conversion and learning a few things along the way.
     
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  13. ValleyFirewood

    ValleyFirewood Addicted to ArboristSite

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    Honda motor is quiet.

    As far as the neighbors, **** em... least that's what I do at my house. I was there first, they don't like it, oh well, move!
     
  14. Ryan'smilling

    Ryan'smilling ArboristSite Guru

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    Relative to what? A Briggs, sure. An electric motor? Not so much. I hate standing next to an air-cooled four stroke motor to split wood. I was gonna go with an electric super split, but went this route instead because I want to split 32" lengths. rps20170607_022231.jpg

    The beam is 100" long, which puts me about 12' from the motor when I'm splitting. A three cylinder Japanese diesel at 2000 RPM is a pretty reasonable volume at that distance. You can certainly have a conversation with your helper. And nothing's vibrating around. If it's level you can set a beer on it while you're working. :)
     
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  15. Sawyer Rob

    Sawyer Rob Addicted to ArboristSite

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    As to electric hp... Bottom line is, in the REAL world, it takes 10 amps at 120 volts to make ONE hp, 5 amps on 240v...

    The difference between the above and "paper" hp is, the 746 watt hp doesn't account for loss' of friction in the turning mass ect...

    So, as an example, if you have a 240v motor pulling 20 amps, it's REALLY a 4hp motor.

    BTW, to ME drinking beer while splitting wood is about like drinking beer at the gun range... SO, I don't know if I can set a beer on my running splitter or not? lol

    SR
     
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