Ok, so with all this great information, would it be safe to say that a 5hp electric motor would run a 22gpm pump. I see in the specs that is says you need a 12hp gas engine to run the 22gpm pump.. If electric to gas is 1:2.5 that would mean that a 5hp electric motor is equivilant to a 12.5 hp gas engine? Also what size lines should I run on the supply and return lines. And last, for now at least, what would be the routing? ex. pump to ram to filter to tank to pump? does that sound about right??
log splitter plans
- Thread starter gould37
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J_J
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Tank strainer, then pump, valve. cylinder. filter, tank.
3/8 or 1/2 in hose.
hyd oil. What ever you use in your tractor hydraulics.
Tank size is supposed to be one gal in tank for each gal pumped.
3/8 or 1/2 in hose.
hyd oil. What ever you use in your tractor hydraulics.
Tank size is supposed to be one gal in tank for each gal pumped.
LD1
Epic Contributor
No a 5hp electric motor will NOT run a 22gpm pump very well. See my posts #13 and #17
Tank size for logsplitters should be about the same as the low pressure flow. So for a 22gpm two stage, 22 gal tank. (as JJ mentioned) For non two stage pumps, it should be 3 to 5 times the flow rate.
For sizing a hose use the formula on this website Hydraulics
And if you solve for D it looks like this
√[Q/(2.45 x v)]
so for a 22gpm pump pressure side needs a velocity of 7-18 so
√22/(2.45x7)= √1.282 = 1.31" ID
√22/(2.54 x 18)= √.481 = .639 ID
So any hose in that size range will work. I would shoot for middle of the road and go with 1"
For return where v = 4-13
√22/2.45x4 = 1.47
√22/2.45x13 = .831"
For suction where v = 2-4
√22/2.45x2 = 2.11
√22/2.45x4 = 1.47
I'd use a 1" pressure line, 1.25 return, and a 2" suction.
Tank size for logsplitters should be about the same as the low pressure flow. So for a 22gpm two stage, 22 gal tank. (as JJ mentioned) For non two stage pumps, it should be 3 to 5 times the flow rate.
For sizing a hose use the formula on this website Hydraulics
And if you solve for D it looks like this
√[Q/(2.45 x v)]
so for a 22gpm pump pressure side needs a velocity of 7-18 so
√22/(2.45x7)= √1.282 = 1.31" ID
√22/(2.54 x 18)= √.481 = .639 ID
So any hose in that size range will work. I would shoot for middle of the road and go with 1"
For return where v = 4-13
√22/2.45x4 = 1.47
√22/2.45x13 = .831"
For suction where v = 2-4
√22/2.45x2 = 2.11
√22/2.45x4 = 1.47
I'd use a 1" pressure line, 1.25 return, and a 2" suction.
Ok, so I am not trying to be a thunder head, and thank you so much for all of your help, but the specs on this 22gpm pump state that you need a 10hp gas motor to run it. I think everyone agrees that at least a 2:1 ratio of electric to gas engine HP. Is this correct? If I get a 5 hp electric motor with a 1.15 rating, then it really is making 5.65hp. Am I correct so far? So that would mean that the electric motor is equal to a 11.3hp gas motor.That is if what northern hydralics said on a web page they stated that the ratio is 2.5:1. Thanks for all the help on the hose side, and if anyone has a good source in the northeast (New Jersey) for a 5x24 cyclinder let me know. Again, not trying to be difficult, just trying to understand and get what I need before doing it twice.
LD1
Epic Contributor
To each his own.
All I can say is try it and let us know but the formula for sizing electric motor to pump that I listed is widely known and accepted as the standard for most all applications. I don't always follow the rules, I'm just relaying information that I have learned, but like I said, if It works, let us know.
I thought I would also add that I have used an air compressor 5HP motor (which isn't really 5HP with only pulling 13.2amps) on dads 11gpm logsplitter and it worket fine for the few peices we used to test it, but with and amp meter on the leads it pilled 22amps, which should require a true 5HP motor
All I can say is try it and let us know but the formula for sizing electric motor to pump that I listed is widely known and accepted as the standard for most all applications. I don't always follow the rules, I'm just relaying information that I have learned, but like I said, if It works, let us know.
I thought I would also add that I have used an air compressor 5HP motor (which isn't really 5HP with only pulling 13.2amps) on dads 11gpm logsplitter and it worket fine for the few peices we used to test it, but with and amp meter on the leads it pilled 22amps, which should require a true 5HP motor
J_J
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LD1 ,
In your figures above for hose sizing, did you consider the fact that when pumping at 22 GPM, pressure is only about 650 psi, and when shifted to high pressure, could be as high as 2500 psi, and 6 GPM.
In your figures above for hose sizing, did you consider the fact that when pumping at 22 GPM, pressure is only about 650 psi, and when shifted to high pressure, could be as high as 2500 psi, and 6 GPM.
LD1
Epic Contributor
GPM is more of the deciding factor on hose sizing rather than psi. The factor for figuring it, is how fast the fluid is moving inside the hose, and 22gpm @ 650 is moving faster than 6gpm @ 2500psi.
And the figures are about right on with what is being used in commercially made logsplitters. On the 11gpm splitter that I normally use, the pressure side is 1/2" and the suction is 1 1/4 which is right according to the formula.
Also keep in mind that I am not the one who created these formulas. I have just been the one to run across them on the internet, interpret them, and pass them along if I believe they are accurate.
JJ- what is your take on the sizing of an electric motor to a hydraulic pump?
I know a lot of people say 2 to 1 or 2.5 to one but the formula that I listed I have seen everywhere and know of many businesses, factories, and mfgs that use it.
And the figures are about right on with what is being used in commercially made logsplitters. On the 11gpm splitter that I normally use, the pressure side is 1/2" and the suction is 1 1/4 which is right according to the formula.
Also keep in mind that I am not the one who created these formulas. I have just been the one to run across them on the internet, interpret them, and pass them along if I believe they are accurate.
JJ- what is your take on the sizing of an electric motor to a hydraulic pump?
I know a lot of people say 2 to 1 or 2.5 to one but the formula that I listed I have seen everywhere and know of many businesses, factories, and mfgs that use it.
J_J
Super Star Member
- Joined
- Sep 6, 2003
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Here is something on service factors.
When sizing motors, service factor rating is a necessary consideration. Most U.S.-made motors have a service life of 1.15, meaning they will handle 115% of normal running current indefinitely without damage. A service factor of 1.0 indicates the motor will tolerate nameplate running current only. This type of motor is being used more frequently, and needs overload protection that trips faster than the traditional Class 20 overload relay.
I would think it would depend on the service factor for the 5 HP motor, and 22 GPM pump. I think the next pump down , the 16 GPM would give more longevity to the log splitter. However, the log splitter is not splitting at 2500 psi very much, and the only difference is the 22 GPM pump will give a faster cycle time, running at the limit of the electric motor.
At one time I had thought of building a log splitter with an accumulator with a check valve to store up energy and accelerate cycle times.
With the lever in neutral, the pump is just recirculating fluid through the valve. It could be doing useful work.
The suction port on the 22 GPM pump is 1 in, and outlet is 3/4, so that is the limiting factor in hose sizing. You can go larger, to reduce any flow restrictions.
When sizing motors, service factor rating is a necessary consideration. Most U.S.-made motors have a service life of 1.15, meaning they will handle 115% of normal running current indefinitely without damage. A service factor of 1.0 indicates the motor will tolerate nameplate running current only. This type of motor is being used more frequently, and needs overload protection that trips faster than the traditional Class 20 overload relay.
I would think it would depend on the service factor for the 5 HP motor, and 22 GPM pump. I think the next pump down , the 16 GPM would give more longevity to the log splitter. However, the log splitter is not splitting at 2500 psi very much, and the only difference is the 22 GPM pump will give a faster cycle time, running at the limit of the electric motor.
At one time I had thought of building a log splitter with an accumulator with a check valve to store up energy and accelerate cycle times.
With the lever in neutral, the pump is just recirculating fluid through the valve. It could be doing useful work.
The suction port on the 22 GPM pump is 1 in, and outlet is 3/4, so that is the limiting factor in hose sizing. You can go larger, to reduce any flow restrictions.
bassgrinder
Member
JJ- what is your take on the sizing of an electric motor to a hydraulic pump?
I know a lot of people say 2 to 1 or 2.5 to one but the formula that I listed I have seen everywhere and know of many businesses, factories, and mfgs that use it.[/QUOTE]
I don't beleive anyone would dispute the formula that you posted however lets look at it
(22 x 650)/(1714 x 85% eff)=9.81 HP required.
a 16gpm pump requires 6HP and an 11gpm requires 3.5HP
What people are saying is that a 5HP electric motors is equal to about 9 to 10 HP gas engines, where in this range will depend on the frame size, speed and torque factor of the electric motor. With this conversion factor (which is as widely accepted in industry as your formula), then your formula actually supports a 5 HP electric with a 22 GPM pump.
Your formula also coincides with what is found with lighter electric driven splitters that use a 1HP motor to replace the 3.5 gas being mated with the 11GPM pump and work just fine. To use the formula to assume you would need a 9 to 10 HP electric motor is comparing an apple to an orange.
Again this link shows info on calculating torque you will see the rule of thumb is 1 HP electric = 2 1/2 Gas
http://www.baumhydraulics.com/files/infobuild/measure_torque.pdf
All the discussion did get me curious to see some examples, so I checked some electric over hydraulic shears and presses here at the shop on site and found
Shear 100Ton 3 HP 18 GPM
Shear 250 Ton 7.5 HP 38 GPM
Press 100Ton 2.5 HP 16 GPM
If I was wanting match a electric motor to the 22GPM pump I would chose
Leeson Air Compressor Electric Motor — 5 HP, Model# 116511 | Motors | Northern Tool + Equipment
It is designed for applications that require high breakdown torque which would be the concern in a splitter.
I know a lot of people say 2 to 1 or 2.5 to one but the formula that I listed I have seen everywhere and know of many businesses, factories, and mfgs that use it.[/QUOTE]
I don't beleive anyone would dispute the formula that you posted however lets look at it
(22 x 650)/(1714 x 85% eff)=9.81 HP required.
a 16gpm pump requires 6HP and an 11gpm requires 3.5HP
What people are saying is that a 5HP electric motors is equal to about 9 to 10 HP gas engines, where in this range will depend on the frame size, speed and torque factor of the electric motor. With this conversion factor (which is as widely accepted in industry as your formula), then your formula actually supports a 5 HP electric with a 22 GPM pump.
Your formula also coincides with what is found with lighter electric driven splitters that use a 1HP motor to replace the 3.5 gas being mated with the 11GPM pump and work just fine. To use the formula to assume you would need a 9 to 10 HP electric motor is comparing an apple to an orange.
Again this link shows info on calculating torque you will see the rule of thumb is 1 HP electric = 2 1/2 Gas
http://www.baumhydraulics.com/files/infobuild/measure_torque.pdf
All the discussion did get me curious to see some examples, so I checked some electric over hydraulic shears and presses here at the shop on site and found
Shear 100Ton 3 HP 18 GPM
Shear 250 Ton 7.5 HP 38 GPM
Press 100Ton 2.5 HP 16 GPM
If I was wanting match a electric motor to the 22GPM pump I would chose
Leeson Air Compressor Electric Motor — 5 HP, Model# 116511 | Motors | Northern Tool + Equipment
It is designed for applications that require high breakdown torque which would be the concern in a splitter.
