Any One Here Knowledgeable On Hydraulics

paintr56

Any one here knowledgeable on hydraulics? I have an old electric company bucket truck for painting. I would like to run the hydraulics off of a small gas engine mounted in the bed of the truck. I am not sure how hydraulic power is measured or how much I would need. Currently it runs off a pump driven by the truck engine this means my old truck sets and idles all day. Anyone willing to try and talk me through the basics?

Thank you Jim Bunton

Vinny

Jim, the pump on the truck is being driven from the pto. The pto spins at a set rate and the pumps are engineered to put out X amount of volume and pressure at that rate. Some how you need to get the info off the PTO and pump and set out to make a match up with a small engine.

My greatest concern though would be reliability. If that little engine fails while your up there, your stuck untill someone gets it going again.

There are small diesles out there, but your really re-engineering here. Its tough.

__________________
Roccies Asphalt Paving
The Right Way Driveway Company
If you say you cant, your a loser. If you say you wont, your a quiter. Which one do you want to be?

mdshunk

I did exactly that with my one small truck. I found the horsepower and RPM requirement be taking the dataplate information off the hydraulic pump and looking it up on the net. A 20 horsepower is what I used, but I only needed 11.

paintr56

It is actually running off a pulley on the front of the engine. I intend to use the current pump as a back up.

Jim

paintr56

What were your hydraulics running? I will see if there is any data on the pump and do a search. Thank you.

Jim

mdshunk

The boom. It's a bucket truck. BTW... you can order a generator with a PTO shaft (the shaft just runs long and sticks out the side). That way, you can have electrical power and a shaft to spin the hydraulic pump. That's what I did.

mdshunk

When you price out hydraulic pumps, relocating that pump onto the smaller proposed lawn mower engine becomes more attractive.

dlcj

wow, i was thinking of doing the same thing. Nice to know im not the only one. We have a old truck with a 30' knuckle boom we use for setting trusses and lifting stacks of decking. That v8 carberated gas engine burns alot of gas just of idle.

paintr56

Are you running with a simple pulley system? If so what is the size ratio on the pulleys? Also do you happen to remember where you ordered the generator from.
Thank you for the help.

Jim

mdshunk

Yes.

I can measure it. I went to the local motor shop with the information on the generator speed and the speed the pump was running when it was on the truck's engine, and they figured the pulley ratio for me and sold me the parts.

Winter Engine Service, near York or Lancaster, PA.

lazerguy

5 gallons per minute @ 2000 psi requires 5.8 HP mechanical power.

Start from there and adjust the figure according to your hydraulic pump's flow and pressure ratings.
Then, as MD did, to give yourself some headroom, use an engine size maybe double the calculated power.
(Engines are sold with nominal HP @ their peak rpm, which doesn't represent changing field conditions.)

For the hydraulic pump, you can get a smaller (less flow) pump, and the boom will still work OK, just slower. However, the pressure psi rating is non-negociable. Your pump must be able to deliver at least the boom's required pressure.
If the pump delivers more pressure than necessary, no problem, the hydraulic system's relief valve will just bleed it down to the right value.