On 2012-04-30, Pete C. wrote:

Ignoramus25949 wrote:

I have a 12v hydraulic power unit similar to this one:

http://goo.gl/UpLJG

The application (what I am trying to accomplish) is to operate this
hydraulic beavertail semi trailer:

http://igor.chudov.com/tmp/Trailking/Trailking-0009.jpg

When OI think about using this pump, I become concerned that it is
operated by a starter-type 12v motor and is desighed for pick-up truck
liftgates or snowplows, that is, very intermittent duty.

This beavertail trailer, while also essentialy intermittent, takes a
lot more work per unit of operation (pull beavertail lock, pull
extension lock, raise tail, extend extension, lower tail). That would
take this little motor a long time and it may overheat and burn out.

Is my concern justified?

I have a few options for powering this trailer. I am basing this on my
assumption that all cylinders are double acting, so not a lot of fluid
is needed.

The options a

1) Install a truck wet kit. cost: $2,000.

2) Use a 12v hydraulic pump that I already have. Cost: Small $$ for
wiring.

3) Use a 115v, self contained power unit that I purchased yesterday
along with a hydraulic H-press for $195. I would take along a Honda
generator that we have to run this pump. Cost: $195, minus whatever $$$
I can get for the press without the hydraulic pump,and the four way
manual valve.

This is a 1.5 HP unit with a continuous duty Marathon motor.

The plus of number 3, as I see it, is that the 115v hydraulic power
unit there, is not intermittent duty, and could do the job, with less
financial risk than plopping down $2,000 on a real wet kit. It would
be slower to work the tail cylinders than the wet kit, due to less
horsepower, but it is not a big deal. It will, however, cost me extra $5
every time the tail is operated, to pay extra hourly salary tot he
operator.

The wet line kit for the tractor is the proper way to do it of course
and $2k isn't much in relation to the other costs related to the semi
and trailer.

The semi tractor cost me $2,300. I am reluctant to double its cost
with a wet kit.

I have seen a Landoll hydraulic everything trailer that was powered by
an onboard hydraulic unit run by a small diesel engine like a 3 cyl
Kubota.

Yep, so have I.

I would consider a small gas powered setup, basically just an 8hp gas
engine coupled to a gear pump and a tank just like a log splitter setup.
You wouldn't have any duty cycle issues, the trailer could be operated
without the tractor if needed and it should cost perhaps $750 to put
together.

My choice number 3 is almost what you are describing, except that
there is a generator and an electric motor in the middle. Like I said,
I already have a portable Honda generator, and since yesterday, have
this single phase 1.5 HP hydraulic power unit.

i