powering a log splitter. ideas?

[BHD]

on my log splitter, I made a power pack, engine pump and tank valve and two quick fittings, (I did use the log splitter pump with the High and low in it),
and set it off to the side of the I beam, (bolted on) and plug into the cylinder, and have used it for other hydraulic needs I many have,
used it for a wire roller, a winch, could use it to lift machinery and pull it with a non hydraulic power unit, like a pickup, I have some Ideas for a super shop press some time.

but it may give some versatility,

my son in law used a electric log splitter, and liked it very much, he like the lack of noise, and could run it at night with out up setting neighbors, or may be it was the built in beverage holder, I don't know for sure, but he was impressed with it.
It used a 2 HP motor,

 

[BHD]

here is a on line calculator, for figuring the horse power need to power a pump you put in the gallons a min, and the psi and it gives you the needed hp, about. and it has a number of other calculators for hydraulics and it use.

Hydraulic

HP is for electric motors, double this for gas engines.

 

[cycle_gator]

Payton:

Discussions about horsepower ratings notwithstanding, your idea to power the hydraulic pump off an automotive engine might work. A couple things to consider:
1.) You need to have a hand throttle to control the motor RPM, unless you want to put your brother in the driver's seat and tell him to keep his foot on the accelerator and maintain a constant RPM

2.) It will take a healthy pulley and belt set to transmit enough HP to the pump, at least a double V-belt if not a triple.

Both of these things are doable, just need to consider how you will accomplish them.

Your 2 HP electric motor is 18A at 110V, if you are running it on 220 V it is 9 amps, Ohms law is immutable. The current draw versus power output on a motor also depends on the type and quality of the windings. Open frame motors are not as efficient and normally the windings are not as dense as drip proof or enclosed motors, but they are cheaper

If you did decide to use an electric motor you would want to monitor the motor current draw. Unless the motor is internally protected, which many utility electirc motors are, an electirc motor will just burn up if it is overloaded, or it will pop the supply breaker if it can pull more amps than the breaker will allow before it burns up the windings. You would only need to put an ammeter on it once, just to know what it is pulling to turn the pump under maximum load. Running with the control valve in neutral, no load, it would be amazing if it draws more than an amp, or two.

An overloaded gas motor will usually just die, think about your rotary lawnmower in heavy grass.

Hope all of this is helpful. Like I said last night get started with the mecahnical design, choose a cylinder large enough to do what you want to do and a pump that will give you the performance you are looking for in terms of cycle time, then figure out what power source to use to drive the pump. If you can rig up your SUV motor, that may be your best, and potentially cheapest, option at least in terms of the build. It will cost marginally more to operate, however, than a smaller gas motor or electric motor. Nicely portable, however.

 

[payton]

I have been doing some cycle time calculations and don't know what length of logs I should plan on splitting. what do most people who sell fire wood split it to? I am thinking 18".

Payton

 

[Redneck in training]

bayerwald® maschinen Holzspalter BW 60/7 E
Here a link to manufacturer of electric splitters. My brother owns one of those and is quite happy with it. He splits only pine and spruce though.

 

[Redneck in training]

not to side track the discussion, but the two pole generator is 3600 RPM, 4 pole is 1800 RPM and a 6 pole is 1200 rpm

most small generators run at the 3600 RPM rate, usually you need to get into the stationary units to get to the 1800, and some small diesels, there are some 6 and multi poled units out there but usually on larger commercial type units, or for special low RPM applications,
the RPM on a generator is what gives it the cycles on AC, so it has to run at a constant, (unless inverter technology is used)

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there is different ways of rating horse power, and I do believe that is where some of the confusion comes in,

for an example there is the way tractors are rated, (Nebraska tractor tests) by draw bar horsepower,
(I have a old military 6x6 truck and it has a 90+ HP motor in it but draw bar power is less than 30 hp, from the manual)

look on any shop vacuum cleaner or electric air compressor nearly, with out fail they will run on a 15 amp circuit, but most likey there only pulling about 80% or the breaker would mostly trip, or about 12 amps,
but 15 amps at 115 volts, is 1725 watts, now divide that by, (750 watts, one hp with out wast) and the max with 100% efficiency is 2.3 HP,
which is most likely closer to 1.75 hp with the voltage drops and other frictions, but what is the sticker on the side of the machine, 4 hp 5 hp, it is not possible, (I am not saying in a locked rotor situation it may pull the equivalent of 4 to 5 hp of electricity, but it is not producing any where near 4 to 5 HP of usable power in that situation.

just like in automotive engines when there HP ratings are made it is with just the bare engine, no alternator, water pump, transmission, any other draw on it power and then it figured,
not a realistic rendering of the engine in the car,

ON small gas engines I figured it took about half of its power to keep it running, at the rated speed,

I know a HP is a HP, but there are ways of rating it to look like more than what is usable,

It all boils down to mass flow of air plus appropriate amount of fuel you can pass trough the combustion engine. Up to certain speed the mass flow is nearly linear with rpm but as speed increases so the velocity of air in the suction resulting in a significant pressure drop. Therefore the engine gets less air than the rpm times displacement would suggest. That is the physics behind the shape of the power and torque curve.
Electric motors produce highest torque at zero speed and only very little unloaded. Start up torque is limited only by magnetic field saturation.
So if you overload combustion engine to the point where the speed drops below maximum torque it will stall. Electric motors will just take more amps increase its torque and keep running (in theory) In real world it has to dissipate heat so, if unprotected, it will burn.
Considering the cyclic nature of wood splitting my guess is that 2 HP motor will work just fine.

 

[SpringHollow]

The 2 - 2.5 multiplying factor is useful for brief loads. Where you run into problems sizing that way is sustained loads. When running a sustained load, that multiplying factor is not accurate.

And with electric motors, you have to be careful how they rate them. A classic example - sellers of saws for homeowners often state a saw motor as generating up to 2 HP when it is a 1 HP motor but under load could briefly produce the equivalent of 2 HP. Amps tends to be one of the better indicators of what the true horsepower of the motor is, especially if you correct for the efficiency factor.

I am getting the parts together to build an electric log splitter. I got a used 5 HP 22V GE motor which draws 15 amps that i will use with my 16 gpm two stage pump. If it does not work, i will add a gas engine. Still need to buy the filter and valve.

Ken

 

[Diamondpilot]

18" logs are common in my area. This means you will need a 24" stroke cylinder. No way to get a 18" log in a 18" machine. They are never cut perfect.

Chris

 

[payton]

18" logs are common in my area. This means you will need a 24" stroke cylinder. No way to get a 18" log in a 18" machine. They are never cut perfect.

Chris

I was thinking a 18" stroke, but leaving ~2" between wedge and plate when the cylinder is fully extended. this way logs up to 20" will fit(assuming the log before it fully split)

Payton

 

[J_J]

Perhaps this web site will help with some of the electric HP calculations. .

Electric Motor Brake Horsepower Calculations

http://en.wikipedia.org/wiki/Horsepower

For those that don't know, electric motors also have an efficiency loss, and sometimes it is equal to the hyd pump to hyd motor loss.

So to those that think you can sneak in an electric motor as a substitute for a hyd motor might use something, like about half or even more, the HP of the hyd pump.

You say I did it and it runs fine, it might, but what tonnage can you claim. While that electric motor is splitting, you need to measure the voltage and amps, and insert them in the formula to determine the actual HP developed. If the electric motor heats up, there is another loss of efficiency, and if operated for long periods, it will surely fail. The service factor will give you a hint.