powering a log splitter. ideas?

[Scotty370]

Payton, again good education here.....Here's some 'food for thought' from one of my bandsaw mill groups. Looks like your 'right-on, about the 2.5 ratio.......~Scotty

http://www.woodweb.com/knowledge_base/Power_Comparison_Between.html

 

[MossRoad]

is their anyway to mount a belt driven pump in a gmc jimmy?

Payton

Yes. There are several companies that make hydraulic pumps that operate off of the belt drives of pickup trucks. They operate off of the belt and are turned off and on with a 12v electric clutch.

Here's a link to a bunch of hydraulic clutch pumps at Surplus Center.
https://www.surpluscenter.com/sort.asp?UID=2009120321382804&catname=hydraulic&keyword=HPCP

Here's a link to some at northern tool.
hydraulic pump clutch from Northern Tool + Equipment

Here's a link to some handy hydraulic calculators at Surplus Center.
Hydraulic

 

[BHD]

on small gas motors it usually takes about twice the HP rating on the gas to equal the electric

so a one hp electric would be close to a 2 to 3 hp gas and a 2 would be close to a 4 maybe a 5 hp,

on a generator, it takes a 8 hp gas motor to get 3500 watts out of it effectively,
(I know 750 watts is a HP, but there is wast in an eclectic motor and many times is closer to 800 to 900 watts, regardless, It can only produce about 4 HP electrically,

as one gets larger the spread is less,

another example, 4 hp gas and electric 1.1 hp
gas air compressor (similar specifications) DeWALT D55250 4 HP 4 Gallon Gas Hand Carry Air Compressor with Control Panel | ToolBarn.com DeWALT D55250
4 HP 4 Gallon Gas Hand Carry Air Compressor with Control Panel

DeWALT D55154 Heavy-Duty 1.1 HP Continuous 4 Gal Electric Wheeled Dolly-Style Air Compressor with Panel | ToolBarn.com
DeWALT D55154
Heavy-Duty 1.1 HP Continuous 4 Gal Electric Wheeled Dolly-Style Air Compressor with Panel
yes there is a little difference in the volume of air, but IT still shows the discrepancy in the HP ratings,

if the Hydraulic pump called for a 8 HP gas motor I would want to use min of 3 electric on it,

YOU may get by with a 2 hp if it was heavy frame motor, with a heavy duty cycle, and the surplus center pump, (it would most likely be a 220 volt set up)

Hydraulicstore.com - Call toll-free 877-778-3533 Mon-Fri 7:30-5:00 Sat 7:30-12:00 Central Time ___________
MTE Auto Hoist Power Unit • Motor is 2 HP 208/230 VAC. Runs at 3450 RPM • 2 GPM. Relief valve is set at 3000 psi. •

https://www.surpluscenter.com/item.asp?UID=2009120318291417&item=9-7503-8&catname=hydraulic
Minimum of 5 HP required for gas engine use.
Flow:
2 GPM HI press. stage
8 GPM LO press. stage

in my experience having a little extra HP is usually better than not having a enough,

 

[cycle_gator]

Just to weigh in here on the gas to electric horsepower disparity. Horsepower is horsepower, the ability to create work over time whether in a gas motor or an electirc motor. Where gas and electric motors differ is in their ability to create torque. An electirc motor creates instantaneous torque when voltage is applied. The torque curve (torque versus RPM) is flat, or nearly so, there are some small friction/heat losses as RPM builds, but essentailly they create the same amount of torque throughout their RPM range.

A gas motor, on the other hand, has a real torque curve with much less torque at idle, peaking at about 75% of rated rpm, then dropping off as RPM approaches rated capability, which, oddly enough, is where maximum horsepower is created and where the horsepower rating of a gas motor is obtained.

Now I am not sure about 2.5 to 1 disparity, but I do know that an electric motor of lesser horsepower rating can deliver the same work as gas motor of greater horsepower rating due to the differing realtionship between rated horsepwer and torque. Perhaps someone with an ME degree can lay out all the formulas and clarify the differences more precisely.

In the meantime, Payton, welcome to the forum and best of luck in your studies. By next quarter you will likely be teaching this class and filling us all in on thermodynamics and stoiciometric efficiency. Also good luck with the wood business. If I had owned the splitter I now have when I was in high school and early college trying to scratch out a few bucks selling firewood, I might still be doing it on the side.

 

[payton]

when you split with a gas motor is it running at max RPM? (when max HP is available) I see where the difference could in the face that maybe a gas engine only has half its rated HP at the rpm it is running at. again i don't know anything about gas powered splitters. does the speed max out on these?

Payton

 

[cycle_gator]

Payton:

That depends on the motor and where it is rated. Your splitter pump will have need of a particular RPM, whether direct drive, or with pulleys and belts, to achieve its rated capability.

In generators, if I remember correctly, a single pole unit must be run at 2200 rpm and a two pole at 1100 rpm. So, for many small gas motors they are running well below the RPM of their rated horsepower, but closer to their maximum torque. In terms of efficiency that is a great place for a motor to be, but it will not produce as much work over each unit of time.

I suggest you go about this by deciding the size of cylinder you want, then figure out how large a hyd. pump you need to operate that cylinder to its capability (remember a hyd. cylinder will move with almost any pressure and rate of flow, but it will not move fast and it will not develop much power with low pressure and flow.) Finally, figure out the size motor you need to run the pump. By the way, a 5 hp electric motor running on 220V will operate on a 20 AMP 220 breaker. 5 Hp requires around 18 amps, Each leg of the phase is carrying half the current, or about 9 amps. Just be sure, if you use some sort of extension cord from the outlet, the wire size is suitable to avoid signficant voltage drop or you will have heat and overload issues.

Have fun.

 

[payton]

Payton:

That depends on the motor and where it is rated. Your splitter pump will have need of a particular RPM, whether direct drive, or with pulleys and belts, to achieve its rated capability.

In generators, if I remember correctly, a single pole unit must be run at 2200 rpm and a two pole at 1100 rpm. So, for many small gas motors they are running well below the RPM of their rated horsepower, but closer to their maximum torque. In terms of efficiency that is a great place for a motor to be, but it will not produce as much work over each unit of time.

I suggest you go about this by deciding the size of cylinder you want, then figure out how large a hyd. pump you need to operate that cylinder to its capability (remember a hyd. cylinder will move with almost any pressure and rate of flow, but it will not move fast and it will not develop much power with low pressure and flow.) Finally, figure out the size motor you need to run the pump. By the way, a 5 hp electric motor running on 220V will operate on a 20 AMP 220 breaker. 5 Hp requires around 18 amps, Each leg of the phase is carrying half the current, or about 9 amps. Just be sure, if you use some sort of extension cord from the outlet, the wire size is suitable to avoid signficant voltage drop or you will have heat and overload issues.

Have fun.

I don't think a real 5hp motor will run on 18A 220V.
BALDOR L1410T MOTOR

that balador is over 20A. I know my 110V 2HP balador is 18A.

I am now thinking I will end up with a hydraulic pump on one of our suv's. might start with something small first though.

 

[Diamondpilot]

I don't think a real 5hp motor will run on 18A 220V.
BALDOR L1410T MOTOR

that balador is over 20A. I know my 110V 2HP balador is 18A.

I am now thinking I will end up with a hydraulic pump on one of our suv's. might start with something small first though.

I think in the end you will find it much cheaper to just buy a cheap Harbor Freight engine and a 2 stage pump. By the time you buy the pump, clutch, hoses, Quick Connects, ect you will have more money in it then a standard system. Remember engineering 101.. KISS!

Chris

 

[payton]

I think in the end you will find it much cheaper to just buy a cheap Harbor Freight engine and a 2 stage pump. By the time you buy the pump, clutch, hoses, Quick Connects, ect you will have more money in it then a standard system. Remember engineering 101.. KISS!

Chris

I am starting to see that it will be about the same price but i think that if i run a 20gpm @2500psi pump off a car engine that it will out preform a log splitter that does 20/6 by a long shot.

Payton

 

[BHD]

Payton:



In generators, if I remember correctly, a single pole unit must be run at 2200 rpm and a two pole at 1100 rpm. So, for many small gas motors they are running well below the RPM of their rated horsepower, but closer to their maximum torque. In terms of efficiency that is a great place for a motor to be, but it will not produce as much work over each unit of time.

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)

~~~~~~~~~~~~~~~~~~~~~~~~~

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,