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feed motor stopping on me!

Started by dovetails, January 04, 2008, 09:34:29 PM

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dovetails

Hi all, Happy new year!   Having a problem with the feed motor on mymill.
It's an 84 lt30,all manual mill. When cutting, the motor that feeds the saw head,will just stop,if I tap my hand on the box or switch, it will take off cutting again.Watching it, the belt is not slipping, the motor stops turning. I looked at the contacs in switch, they seem to be fine, and I see nothing loose in the control box either, so not sure what giving it a slap does to make motor start again. Will work fine for several boards,or act up several times on each board. Speed of feed don't seem to make a difference either, fast or slow,still will just quit then work fine again.  Any one run into this problem before? ideas?   Mill only has 90 hours on it, but has been out in weather for years,covered. Hate to buy a new motor,and still have problems with it.
1984 wm lt30,ford 3000 w/frt lift,several chain saws, 1953 model 30 Vermeer stump grinder,full wood working shop, log home in the woods what more ya need?

ljmathias

Same thing happens on my LT30 1986 vintage- if I take the control box apart and clean the contacts, fiddle with the wires and tighten up the wire set screws, it runs better for a while.  All in all, I think it's just a bad design for the control box but it's too expensive to replace (at least for me) so mostly I just bang on it and it works till it gets real bad then I take it apart and do the foo-foo magic dance...  Problem is very intermittent on mine and hasn't happened in a while actually.

One thing to watch out for:  it can get stuck in flat-out fast all of a sudden and you better be quick or a band will break and fly everywhich way (don't ask me).  Just be ready with your hand on the switch while your cutting.  Good luck.

Lj
LT40, Long tractor with FEL and backhoe, lots of TF tools, beautiful wife of 50 years plus 4 kids, 5 grandsons AND TWO GRANDDAUGHTERS all healthy plus too many ideas and plans and not enough time and energy

Tom

I'd check for worn brushes or that the brushes aren't seating properly in the motor.

Then replace the rheostat, or whatever that speed control thingy is called.   Sometimes the three wires that connect it to the power box inside are loose.  A little screw driver will tighten them up.

dovetails

Quote from: ljmathias on January 04, 2008, 09:51:00 PM
Same thing happens on my LT30 1986 vintage- if I take the control box apart and clean the contacts, fiddle with the wires and tighten up the wire set screws, it runs better for a while.  All in all, I think it's just a bad design for the control box but it's too expensive to replace (at least for me) so mostly I just bang on it and it works till it gets real bad then I take it apart and do the foo-foo magic dance...  Problem is very intermittent on mine and hasn't happened in a while actually.

One thing to watch out for:  it can get stuck in flat-out fast all of a sudden and you better be quick or a band will break and fly everywhich way (don't ask me).  Just be ready with your hand on the switch while your cutting.  Good luck.



Yup, it's done the speed up deal too!  Will have to take cover off and check screw tightness also as Tom said.
1984 wm lt30,ford 3000 w/frt lift,several chain saws, 1953 model 30 Vermeer stump grinder,full wood working shop, log home in the woods what more ya need?

pineywoods

Question. When the forward motor quits, does the up/down still work ?If not,there's a small automatic reset circuit breaker in there that will kill both motors. If up/down still works, then Most likely corroded contacts on the fwd/rev drum switch. You may have to remove the mounting screws that hold the switch in place to get at the ones in the rear. there's a bunch of  contacts on that switch. clean and coat with contact grease. Next most likely is a loose connection going to the circuit board mounted under the top of the control box. Could be the circuit board itself. IF it's the speed control pot itself, wiggling the control knob should temporarily get things moving. Intermittent electrical problems can be a real pain.
1995 Wood Mizer LT 40, Liquid cooled kawasaki,homebuilt hydraulics. Homebuilt solar dry kiln.  Woodmaster 718 planner, Kubota M4700 with homemade forks and winch, stihl  028, 029, Ms390
100k bd ft club.Charter member of The Grumpy old Men

DR_Buck

Do the older mills use a variable resistor for feed speed?    If so, I'd check that out.   The carbon on the rheostat could be worn, burned, or just dirty giving an intermittent contact.    Had that problem on my LT40, and a new speed rheostat cured it.
Been there, done that.   Never got caught [/b]
Retired and not doing much anymore and still not getting caught

dad2nine

I have had that same problem on my LT40 - and could not figure out for the life of me what was causing it - till one day I happened to notice a piece of bark on the chain. Yep sure enough just the right size when the gear hit it, it stopped the head dead in it's tracks. I solved it by loosing up the chain considerably. Don't quote me on this but I think the manual says to tighten the chain so the is like 7 or 8 inches sway in the middle from the top of the bed, mine is way looser than that and haven't had a problem since. It probably doesn't help that I run with the dust  hose up either. My mill sits under a shed and plus I don't like walking in a pile of dust that's left on the operator side right where you walk when you let the dust hose down. With the hose up the loins share of the dust blows about 6 -8' away from the mill and out the back of the shed. I'll come by and scoop it up with the bobcat, beats shoveling my _ _ _ off and no more climbing over dust mounds or dust filled boots either...

Minnesota_boy

Open up the control box and re crimp the wire connectors that go to the control board.  Check that the connectors are tight on the connections too.
I eat a high-fiber diet.  Lots of sawdust!

Brucer

You know it's not the belt slipping.

It could be a piece of bark on the chain -- that happens to me once every few days, but thumping the control box doesn't fix it.

It could be the motor failing, but that's more a gradual deterioration and I wouldn't expect the thumping to fix that either. Ditto the brushes.

That leaves:
- a loose wire, probably in the control panel.
- control switch failing.
- dirty contacts in the control switch.
- faulty speed control board.
- worn out potentiometer (the thing the speed control knob is attached to).

I replaced my potentiometer last month. The mill was behaving pretty much as you describe, and slowly getting worse. The new pot fixed things instantly. Fortunately I had already confirmed that was the problem, so I didn't have to try a whole bunch of fixes to find the right one.

At pot' typically fails in two ways. The first is a worn or damaged spot inside (water leaking in will damage it). The classic symptom is when the loss of feed happens at exactly the same spot on the dial each time.

The second way a pot' fails is when the wiper inside lifts off the resistance surface. That's usually caused by a slightly loose shaft and that was what happened in my case. I found that wiggling the control knob would stop and start the feed no matter what the speed setting.

The "wiggle test" is nice 'cause you don't have to take anything apart to perform it :). If that causes the problem (or fixes it), pop the panel and see if any of the three wires to the pot is loose (the newer ones are soldered on). If it's not a loose connection, try replacing the pot'.

Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

dovetails

yesterday I cut up some oak and pine logs. Everything went fine for about 2 hours,then it started doing it again. I ran at different speeds,depending on how well it was cutting. Changing the speed knob didn't seem to make any difference in the stoping,neither did holding the foward / reverse switch in diferent positions. When the motor stops,just a tap on the cover of the control box will make it start again.Sometimes it will finnish the cut, or I might have to tap it several times to get to the end of cut. Seemed to get worse as I went along, making me think it may be something getting hot and loseing connection.Will tear into it today, and see if I can find the problem. will also try the  wiggle test on it. Thanks for the ideas guys!
1984 wm lt30,ford 3000 w/frt lift,several chain saws, 1953 model 30 Vermeer stump grinder,full wood working shop, log home in the woods what more ya need?

dovetails

Took the cover off it, tightened the little screws holding the wires in,they didn't turn much, but I guess it might have been enough that they could lose contact.So far seems to be doing ok,will find out better when I cut some more boards.
1984 wm lt30,ford 3000 w/frt lift,several chain saws, 1953 model 30 Vermeer stump grinder,full wood working shop, log home in the woods what more ya need?

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