OT. How much power do hydraulics really take?


[Follow Ups] [Post Followup] [Dodge Power Wagon Forum]


Posted by David Sherman [216.18.131.154] on Sunday, February 21, 2010 at 12:53:56 :

I don't have much experience with a complicated hydraulic system, but I've been learning thanks to my bucket truck that blew out its oil filter again, after the first time that I mentioned before. This time I was up in the bucket and all I could do was watch the oil spew out while the engine kept running with a dry system. Before too long, somebody came by and handed me a ladder so I could get down, fortunately. I took off the filter base, which had been added by a previous owner and was on backwards so the bypass valve couldn't work, but that wasn't why the filter blew out, since there should have been no obstruction between the filter and the tank. Since I couldn't find any other problem, I got a new hose to go from the filter to the tank, in case the old one has a deteriorated lining that was coming loose and blocking it. I used the bucket a little bit after that, but don't trust it for going very far yet.

Anyway, I got to thinking about how much gas this thing uses running the hydraulics. It has a big-block GMC gas engine with a PTO driving the hydraulic pump. The engine has a hand throttle, but no real governor, so the RPMs drop noticeably when you're moving the boom, even though I don't think it really draws that much power. That also means you have to set the RPMs pretty high so it won't stall when using the hydraulics, which contributes to more gas usage. The pump is no doubt not in pristine condition, based on the murk and slime in the first batch of oil that spewed out of the system when the filter blew the first time.

I'm thinking that the actual HP needed to move things around is fairly minimal because they don't move fast. It's not like an excavator where you're trying to dig as fast as possible. This is a big bucket truck, with a 60 foot boom. Believe me you do NOT want to move the boom fast, because it has about a 10 foot fiberglass section in the top boom that springs back and forth like a giant fly rod if you're not real smooth on the controls. It has a swivel base, a pair of outriggers, two boom joints, and no sliding boom section.

What I'm wondering is whether a small gas engine with a direct-mounted hydraulic pump would do the job. Chinese copies of 6 to 12 HP Honda engines are available new for $100-$250, and I have a couple of hydraulic pumps somewhere, though they might not bolt on directly and I might have to get a new one. This would save a lot of gas and maybe be more reliable too. The unknown is how many HP I really need to run the boom up and down at an acceptable speed. I have absolutely no idea about that. I suppose I could leave the PTO pump in the circuit too as a backup, unless it leaks backwards when not being driven. The Genie Lifts seem to have a pretty small motor in them, but they may be lighter.



Follow Ups:



Post a Followup

Name:
E-Mail:
Subject:
Message:
Optional Link
URL:
Title:
Optional Image Link
URL:


This board is powered by the Mr. Fong Device from Cyberarmy.com