Press motor stalling under load

B

BKT

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Feb 15, 2016
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Having an issue with a press I put together. When the motor goes under load the motor stalls out completely. Its a 2 stage pump powered by a 5 HP motor. Doesnt seem like its switching to the 2nd stage.

Video is here:
 
Need more details. 5hp, what RPM? 240v? What is pump displacement in high and low? Cylinder size?
 
5 HP, 3600 RPM, 240v.

Pump is 11 GPM/3.4 GPM. Cyl is 5"x16" with 2" rod.
 
Do you have a pump number exactly? Is it an 11gpm log splitter pump from Surplus Center?
 
You should never stall a motor.
Do you have overpressure relief ?

As others mentioned, we cant help without specs of your pump, motor & cylinder.
 
At 3600 RPM and .757 displacement that pump requires slightly more than 5hp to develop 650 psi required to shift into high pressure (low displacement). That's why it's stopping your motor. In the Q&A they say it requires just less than that but my math says 5.14 hp.

The pump description says the unloader adjustment is preset to 650, but adjustable from 400 to 900. If you adjust it down to 400-500, you will be able to shift into high pressure.
 
You have a number problem. Your motor is quite under powered for that pump. General rule of thumb is 1HP = 1GPM @ 1500 psi. You did not say what pressure your running at. But if your running at 3000psi then that pump would need 3000/1500=2x3.4=6.8HP. But let's say your running at 2500psi. 2500/1500=1.66x3.4=5.66hp
With that being said you would need to run at or close to 2000psi which with your cylinder would give you a hair over 19 tons.

Your low pressure stage would need to be set to around the 650psi range according to the numbers. There is no way that a 5HP gas engine would run this pump. You could be switching to the second stage and then over loading the motor. I think where things went south is motor selection. Most people pick a high flow pump like you did but then get a motor at 17xx rpm. It halves the pump flow cutting required HP in half and reducing noise.
 
You did make sure it's wired to 220v right?
 
May or may no help; I run a similar set up with a 5 hp motor, but it's 1750 rpm & a 16 gpm two stag pump. Never comes close to stalling the motor.
 
I agree with Don, I'm running a 16gpm dual stage pump with a 5 hp 3450RPM motor with no problem. Pump recommended hp raitings are typically for gasoline engines. There is a 8/5 conversion factor for gas to electric, 8hp gas can be replaced with a 5hp electric.
I think JT's suggestion to check the voltage is a good one. If your voltage is correct, check to insure your motor is jumpered for 230V and not 440v/460v.
Jim A.
 
Well I guess I'd like to try adjusting the unloader valve first to see if that will help before having to replace parts. Any idea where I can find that on the pump?

A little disappointed as I went over this whole setup with the guys from Surplus Center and they said I should have no problem.
 
I put a meter on the two leads, and its coming out to this. Looks to me like its running at 110v? Sorry I have absolutely zero experience with electrical.

BVgcZdN.png
 
You should have four leads, two hot, one neutral, and on ground.
 
I have four leads going into the motor, and they are wired in pairs. I put the meter on the two wires coming out of my extension cord going that I wire in to the two leads going into the motor. I have an extra wire in the cord but I dont even know where I would wire that? I have the ground screwed into the ground screw on the motor.
 
BKT said:
I have four leads going into the motor, and they are wired in pairs. I put the meter on the two wires coming out of my extension cord going that I wire in to the two leads going into the motor. I have an extra wire in the cord but I dont even know where I would wire that? I have the ground screwed into the ground screw on the motor.
Click to expand...

Wait what? Can you snap a picture of this? Sounds like you're running the motor off a single leg.
 
The four yellow wires is what I have coming out of the motor. It tells me to join these and wire them to my leads to wire for CW or CCW rotation. I wired my black and white wires for power, I have the bare wire connected to the ground screw on the motor, and the extra red wire I have running to nothing.

4pVTo60.png
 
Oh, no. You're running your motor off a single leg. The Red to white = 120v, black to white = 120v, Red to black = 240v.

Look at your motor wiring diagram. Or post a picture of it.

The plus side is this is an easy fix and not something to do with your hydraulics. Attach the red and black to your motor leads and wire nut the ground and white together with a 3rd piece coming out and going to your ground screw.
 
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