Electric Hyd. log splitter

[okclumberjack]

I built a log splitter with a 220 volt 3 hp electric motor( sorry no pics) it works ok but seems like it could be better will split most wood but some of the harder stuff it won't split, i just installed a gauge on the line between the valve & the pump to ck pressure but haven't run it yet, when i try & split a piece of difficult wood it just stops, the motor doesn't bog down so my thinking it's not the motor, the instructions from the valve say there is a pressur adjustment screw to adjust pressure but doesn't tell which way to turn the screw, also are these valves set low from the factory, thinkg need to ck pressure then adjust up some am i on the right track also the unit has a 2 stage 16 gal/min pump & a 4 inch 3000 psi cylinder.??? thanks

 

[N8ghz]

With the gauge on there it should be simple to figure out which way to turn the adjusting screw by loading it up & turning the screw one way or the other while watching the gauge. I am guessing that the pump is switching from Hi gpm low pressure to Low gpm high pressure, otherwise I doubt if it would split anything but maybe pine 2x4's?

Maybe your couplings are slipping?...does the pump stop turning? I doubt that the relief in the valve is set from the factory too low. Is it a new valve? If not, who knows where it is set at from whatever it was used on before you got it..

 

[J_J]

The pump unloader valve in the two stage valve might be hanging up and therefore can not develop the high pressure.

Put a gage on it and you will see when and if it shifts. I believe it shifts about 650 to 700 psi on the two stage pumps.

 

[J_J]

Here is a breakdown of Harbor Freights 11 gal two stage pump. Probably similar in construction to all the two stage pumps.

http://manuals.harborfreight.com/manuals/99000-99999/99742.pdf

 

[okclumberjack]

thanks JJ will run it this week end to see what happens will get back & let you know, I just keep thinking this thing should split steel will let you know what i find thanks

 

[N8ghz]

Here is another pdf that shows the hydraulic schematic of how the hi-lo pumps work.

Note that the pump section specs are in MLiters.

http://whhydraulic.com/images/Wood splitter pumps.pdf

 

[6sunset6]

I built a log splitter with a 220 volt 3 hp electric motor( sorry no pics) it works ok but seems like it could be better will split most wood but some of the harder stuff it won't split, i just installed a gauge on the line between the valve & the pump to ck pressure but haven't run it yet, when i try & split a piece of difficult wood it just stops, the motor doesn't bog down so my thinking it's not the motor, the instructions from the valve say there is a pressur adjustment screw to adjust pressure but doesn't tell which way to turn the screw, also are these valves set low from the factory, thinkg need to ck pressure then adjust up some am i on the right track also the unit has a 2 stage 16 gal/min pump & a 4 inch 3000 psi cylinder.??? thanks

I have a similar set up with a 2hp motor and an 11 gpm double stage pump.
It splits everything in sight. One of two things Pump not shifting to high pressure or relief valve in the 4 way bypassing. Gage will tell you. 99% pressure adjustments are clockwise for higher pressure. My money is on the relief valve in the 4 way. I have had them back out .
Question Your motor never overheats? I just built a new splitter with a 5hp motor and 16 gpm pump. 4.5 cylinder. Have not run it yet.

 

[MulemanNE]

Just noticed your new splitter specs and am very interested in how it is working out for you. I have a 5hp motor (23 amps) and am planning a build with a 4.5 inch cylinder. Not sure on pump size, torn between 13gpm and 16gpm. Are you happly with the 16? Also what size rod is in your cylinder and would you do it the same way again. Thanks!

 

[6sunset6]

It's working great. 16 gpm pump pressure set at 2000 psi. 3/4 hoses on pressure 1 inch on return. 1/2" to the cylinder. cylinder is 4.5 x 20 2.25 shaft. That size motor single phase needs a 30 amp breaker and #10 wire .

 

[xring100]

I built a log splitter with a 220 volt 3 hp electric motor( sorry no pics) it works ok but seems like it could be better will split most wood but some of the harder stuff it won't split, i just installed a gauge on the line between the valve & the pump to ck pressure but haven't run it yet, when i try & split a piece of difficult wood it just stops, the motor doesn't bog down so my thinking it's not the motor, the instructions from the valve say there is a pressur adjustment screw to adjust pressure but doesn't tell which way to turn the screw, also are these valves set low from the factory, thinkg need to ck pressure then adjust up some am i on the right track also the unit has a 2 stage 16 gal/min pump & a 4 inch 3000 psi cylinder.??? thanks

To calculate where your relief valve should be set in the valve to prevent motor stalling lets assume that the second stage is 3.6 GPM at 2000 kPa should be approximate. It could be 3.5 gpm it all depends on the pumps output curves this number also changes with pressure if you had the curves you could get exact numbers but we can guess.

HP= q p/ 1714
Where
HP = Horse power of motor
q = flow rate of pump gpm
p = pressure
rearrange the equation to solve for pressure HP * 1714/ q = P 3 Hp * 1714/ 3.6 gpm = 1428 psi if you had a 5 hp you could set the pressure up about 2380 PSI obviously you need the relief valve set below this limit for whatever hp or you will stall the motor.

P = F/A => P A = F

4" cylinder area = PI D^2/4 = 12.56 in^2
using your 3 hp motor
1428 lb/in^2 * 12.56 in^2 = 17944 lbs = 9 tons of splitting force I'm not surprised you can't split anything difficult

if you upgraded to at 5 hp you would have 15 tons of splitting force this should be sufficient for most wood
you either need need to go for a bigger motor or downsize the pump if you need more splitting capacity

Hope this helps Merry Christmas