Help me understand a little about hydraulic system

[wkheathjr]

I am no expert or have any knowledge of hydraulic system so bear with me.

I was wondering if this is possible??

Instead of having three gas engine (5hp each) for three different machine, is it possible to get a 15HP gas engine and connect the hydraulic pump to it, and use the pump connected to three different motors to get machine work at same time or at different time (with control system)?

If yes, can you suggest me a good website or maybe book where I can read more about it to understand hydraulic system better.. So I can calculate the HP rating and all properly for what I am about to set up.

BUT BUT.. if it is cheaper to have three gas engine than to have a hydraulic system then maybe I should just stick to gas engine because of my budget unless it is really worth it in long run!

Thank very much in advance for answering my question!

 

[RedDirt]

What you suggest is possible but one thing I learned in hydraulic classes (and real world) the prime advantage of hydraulics is the flexibility to have power at places remote from the power source NOT cost.

Your proposal sounds expensive w/ a couple hundred $'s per pump & motor and another couple for the three spool valve. Add hoses and fittings and it looks like a minimum of $700 -$1000 not including your motor.

For a hydraulic reference it's hard to beat the Industrial Fluid Power series by Womack Educational Publications. Look on Amazon.

 

[wkheathjr]

RedDirt,

Thank for the follow-up. I guess it would depend on how we are looking at the situation itself. The 15-18HP motor would run maybe $500-800 in the market nowadays, right? The we add the $1,000 for hydraulic system making it roughly $2,000 ballpark.

With three gas motors and I would need two 15+HP and one 6HP engine. The 6HP cost $300-500 so basically in long run it is probably better to just go with hydraulic system and one motor?

But the question is.. will 16HP gas motor be enough to feed the power to hydraulic pump so it can run two motors(6hp and 15hp) at same time maximum. It will never operate three motors at one time.

 

[RedDirt]

Sorry, I didn't mean to imply I was an expert. My hydraulics courses were 30+ years ago and I have only dabbled since. Without research I'm not sure if the 16HP gas motor will work but someone else will know. My guess is you won't have sufficient power from a 16hp gas motor. Generally for every 1hp of drive power you can produce 1gpm flow at 1500 psi.

But HP is a measure of "work" vs speed. Your hydraulic power output may not convert directly to input power depending of various possible gear reductions that may be required. There are also power losses to consider when converting the rated gas HP to hydraulic HP not to mention where the rated gas HP is measured; max torque, max speed, etc. Some specs are pretty liberal (to market 'less-for-more'). Not sure but I recall something around 85% efficiency factor "good" for a hydraulic system.

You may find some useful design ideas at this link (and their links).
Hydraulic and Pneumatic Design and Engineering - Engineers Edge

To better answer your 16HP question someone will likely like to know what the three tools/implements you will be running and their rpm's. Also important, are they started under a load or can they run up to speed before engaging?

 

[wkheathjr]

No no, no one is implying anything at all.

The question I asked about if 16HP is sufficient enough is based on little knowledge when I was inquiring about a machine couple of years ago. It required a skid steer to run 75HP+ so it could pump enough GPM of hydraulic through the machine, but that machine is really a monster.

The motor will be speed up first before getting to work, and really it is simply a bandsaw milling machine.

I happen to know someone who rebuild heavy equipments for a living and I just sent him email 15-20 minutes ago asking him few questions that maybe he or his co-worker can help answer. We will see...

 

[kennyd]

Here are some online calculators that may help:

Surplus Center (links on the left)

Baum

Army Hydraulic Manual

 

[wkheathjr]

After doing some self-researching, I can say I have a little better understanding of the system, but I am lusting for more information that apparently can't be found anywhere.

I am looking for calculation of how you can compare the HP of hydraulic motor VS HP of gas motor?? The calculation of GPM *PSI / 1714 = HP is to get the result of HP your gas motor will need to have to feed the power to hydraulic pump.

Suppose I want a high-RPM hydraulic motor that can match the HP/speed of gas motor then what is the calculating formula you use?

Another question is.. suppose I want to run two high-speed(RPM) hydraulic motors that is running at 1,800PSI (cont) at 15.5GPM(cont) with occasional usage of smaller hydraulic motor running at lower PSI/GPM rating then what kind of pump do I need?? One that will run at 3,000PSI (cont) and say 20GPM (cont)???

Just so you know, I am trying to make a wood grinder using hydraulic system...

I understand that although some answer or input may follow, it doesnt mean I shouldn't check with an expert before purchasing the motors.

 

[wkheathjr]

Found this info I was looking for:

1HP Electric Motor = 1 1/2HP Hydraulic Motor
1HP Gasoline Motor = 2/3HP Hydraulic Motor
1HP Hydraulic Motor = 1 2/3HP Gasoline Motor
1HP Hydraulic Motor = 2/3HP Electric Motor.

Now I just need to understand the system a little better.. such as how to calculate how many GPM/PSI the pump need to be for # of cylinder or gear pump or hydraulic pump all together. Guess no one know how to explain??