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Wood-Mizer Hydraulic Pump "HOLD ON" Circuit?

Started by Ga Mtn Man, March 29, 2014, 09:02:31 AM

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Ga Mtn Man

I started noticing the other day while sawing just how much the hydraulic pump is cycled ON/OFF while nudging a log into position and it got me to wondering - How hard is that cycling on the pump and solenoid and would there be any benefit (or cost) to adding a simple "HOLD ON" circuit to the solenoid?  I'm thinking a simple MOSFET with and adjustable R/C time-constant circuit set to hold the solenoid ON for 1-3 seconds after any hydraulic lever is released.  Just throwing the idea out there for discussion. :)
"If the women don't find you handsome they should at least find you handy." - Red Green


2012 LT40HDG29 with "Superized" hydraulics,  2 LogRite cant hooks, home-built log arch.

drobertson

No doubt about it on the cycling of the pump and solenoid,  I had to replace the brushes once at just over 2000 hrs, the solenoids have held up to this point,  It may be a bad thing, but I where a radio head set while sawing, so I don't here as much of the goings on with the solenoids and motors.  I'm not too sure I would want any more electronics on the mill,            david
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

Magicman

I do not see it as a matter of great concern because those solenoids last several years.  I know that I give mine a real workout during a day's sawing. 
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

backwoods sawyer

Working a large odd shaped log and get heavy handed on the hydraulics and you are changing a set of fuse's $20 and well it takes time to change the fuses in the small box, but a pair of 12" needle nose pliers will help.
Battery life is already being pushed with the amount of draw the pumps pull. The solenoids use a heavy layer of silver and last for years, last time I changed mine was when there was a fire in the hydraulic box back in 06. I don't see that the pro's outweighing the con's.   
Practice flowing from one lever to the next and you can load, rotate and set a log without the pumps disengaging but listen for battery drain when working heavy odd shaped logs and give the alternator a chance to keep up.
Backwoods Custom Milling Inc.
100% portable. . Oregons largest portable sawmill service, serving all of Oregon, from our Backwoods to yours..sawing since 1991

Red Good

Is every one still using fuses . Has no one switched to circiut breakers of the same amps ? I like them because they pop and reset . Just a thought . Red
Stihl 211C saw
Massey 135 deisel tractor with a front loader
Can Am 800 max quad
2001 Chev S10 pick me up
Home made log arch

Delawhere Jack

Quote from: Red Good on March 29, 2014, 12:53:30 PM
Is every one still using fuses . Has no one switched to circiut breakers of the same amps ? I like them because they pop and reset . Just a thought . Red

Jim Rogers and I switched to breakers. 100A time delayed. The type they sell at auto parts stores for boom cars. Pardon the blurry photo. Made the change after installing a $28 "marine grade" fuse which I blew immediately after installing.



 

backwoods sawyer

can you stack them, need 200 amp for two pumps.
Backwoods Custom Milling Inc.
100% portable. . Oregons largest portable sawmill service, serving all of Oregon, from our Backwoods to yours..sawing since 1991

Chuck White

Jack; I switched from the fuse to a CB about 5 years ago.

It's the same CB as the one you posted above, I think I paid around $25.00 for it and it's only tripped once or twice since I installed it!

~Chuck~  Cooks Cat Claw sharpener and single tooth setter.  2018 Chevy Silverado and 2021 Subaru Ascent.
With basic mechanical skills and the ability to read you can maintain a Woodmizer  LT40!

stavebuyer

On my LT70DCS the circuit came with a delay to keep the pump running for about 3 seconds. Great idea for log positioning as you described but wrecks havoc on the power strip by arcing if you move the head before the pumps cycle off.



Brucer

There's many types of hydraulic valves, and many ways of plumbing them.

On a WM, if the pump is running and a valve isn't open, all the fluid the pump is moving has to flow through a relief valve. So -- do you want to start and stop your solenoid and pump a lot, or use the relief valve a lot. One or the other is going to see a lot of wear.
Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

Ga Mtn Man

So the guys that are using external pump units (ElectricAl, bibbyman) are constantly hammering the relief valve?
"If the women don't find you handsome they should at least find you handy." - Red Green


2012 LT40HDG29 with "Superized" hydraulics,  2 LogRite cant hooks, home-built log arch.

Brucer

Maybe! I took a closer look at the diagrams and there are a bit ambiguous.

There is a type of control valve that will send the fluid back to the tank when the valve is centered. You can daisy-chain these valves together so there's a flow path back to the tank until a valve is operated. It's typically called "power beyond" -- when you operate a valve, it cuts off the flow to any valves that follow it in the chain. The WM mills I've used don't use this type of valve -- you can operate more than two cylinders at once.

Looking at the diagrams (with a magnifying glass), they appear to be using a type of control valve that dumps fluid to the tank until a valve is operated, but doesn't daisy chain the pressurized fluid from the pump. But I only see that on one diagram. All the other diagrams show a conventional closed center valve, which would cause your relief valve to operate.

I suspect they may have changed their valve configuration at some point, but I don't know when.

How to find out? Ask Bibby or Al directly, or do a simple test. Open up your control box and manually activate the micro switch that starts the pump. If your control valves bypass the relief valve when they aren't activated, you'll just hear the pump running. If the flow is going through the relief valve, you'll hear it screaming above the motor noise.
Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

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