Power Beyond Option Questions

JohnMiller3 · Jun 11, 2003

...a Power Beyond kit on my tractor but never considered that it could actually add power to my tractor...

Hi Rob,

I added Power Beyond... an lo and behold... much much more Power!!! I'm convinced...! /forums/images/graemlins/blush.gif/forums/images/graemlins/tongue.gif

Even my new weed wacker has this new found power... /forums/images/graemlins/wink.gif

Beyond... anything I could possibly imagine... /forums/images/graemlins/shocked.gif

MikePA · Jun 11, 2003

I REPEAT POWER BEYOND IS NOT a JD marketing term. 
jrlichina, not that your information needs any more proof, but just for the heck of it, I visited the John Deere web site and did a site search for 'power beyond'. I got 37 hits. While I didn't look at all of them, the ones I did look at I noticed there was no trade mark indication behind John Deere's use of power beyond like there is when they refer to other JD featues such as VacuMeter or SeedStar.

uhmgawa · Jun 11, 2003

( I REPEAT POWER BEYOND IS NOT a JD marketing term. )

Egad. Hopefully avoiding further fanning of the flames..

Power Beyond seems to be [or has become] an industry default
feature 'name' in most hydraulic texts I've read.

The technical goal is simply to allow additional valves to
be plumbed into an existing open-center / fixed-displacement
pump hydraulic circuit. Basically this allows full pressure
flow from the input port to the PB output port (rather than
tank output) when all section valve(s) are idle.

A PB output is necessary to feed downstream valves as a
tank output port typically is not designed to withstand full
input pressure. Also valve functionality is affected if the
tank port is not allowed to vent into a low pressure outlet.

jrlichina · Jun 11, 2003

Actually the to tank port named "OUT" does not see full line pressure. In an open center system when all controls are in neutral there is very little pressure going in as well as out(The PB port gets unrestrcited/uninterrupted fluid flow). The pressure developed is a result of resistance to flow of the fluid. Like when actuating a cylinder the more load placed against it the higher the line pressure is to that circuit. When load force(pressure) excceds the relief valve setting the flow is then by-passed to the OUT port. This by-passed fluid is not at the high circuit line pressure, but rather at about the difference in the relief valve setting and the maximum pressure the pump can produce. The exhausted fluid from the circuit is also routed to the OUT port which again is not under high line pressure. And yes the tank should be vented

Anonymous Poster · Jun 11, 2003

( Please feel free to check out any text books on fluid power to see for yourself.)

I would be interested in picking up a good hydraulics textbook--not to see if JD owns "Power Beyond" I hasten to add--but for my own edification. Can you recommend one?

SnowRidge

jrlichina · Jun 11, 2003

Well most good books are really expensive $100-$200 bucks. But here's a link to all the basics that should get you up to speed in general. Hydraulics

Anonymous Poster · Jun 11, 2003

Thanks for the link. I'm downloading the PDF now.

It should be a good read. I briefly looked at the preface on the web page, and it's comforting to know the information is applicable to the most extreme environments. From the preface: "The contents of this manual are applicable to both nuclear and nonnuclear warfare."

I hope so; you never know. /forums/images/graemlins/cool.gif <--note radiation goggles

Thanks again.

SnowRidge

uhmgawa · Jun 11, 2003

( Actually the to tank port named "OUT" does not see full line pressure.)

Yes, when normally and properly configured. However if an
attempt is made to use an open-center tank out port as a
substitute for a PB port, full pressure can exist at the
tank port. This can occur if a downstream valve (now being
supplied by the upstream tank output port) is actuated
causing resistance and pressure to rise to the relief
valve limit.

Thus PB provides a safe high pressure capable path to
direct input port flow downstream when all valve body
spools are idle. If a valve does not have a PB port,
all input flow is directed to the tank out port under
low pressure when all spools are idle.

( And yes the tank should be vented)

My terminology may have been unclear. The tank out port
"vents" the fluid entering the input port to the tank,
which offers essentially no resistance thus the circuit
pressure approaches zero. "vented" as above refers to the
tank being open to atmospheric pressure, which allows for
low (near zero) pressure in the return fluid circuit.

Anonymous Poster · Jun 11, 2003

From the 1982 Edition of John Deere's Fundementals of Service Manual titled Hydraulics, Compact Equipment, Power Beyond is defined in the Definition of Terms section as:

"An adapting sleeve which opens a passage from one circuit to another. Often installed in a valve port which is normally plugged."

This sounds pretty generic to me.

Jeff

uhmgawa · Jun 11, 2003

( Well most good books are really expensive $100-$200 bucks. But here's a link to all the basics that should get you up to speed in general. Hydraulics )

That is a good reference though the digitized illustrations
are somewhat coarse. Here is a pointer to a printable (PDF)
version:

http://www.adtdl.army.mil/cgi-bin/atdl.dll/fm/5-499/new5499.pdf

Though it is directed mainly at certification test study,
this has been of use as well:

https://www.ifps.org/DocumentFiles/MHTManual0503.pdf