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up down motor WM problem

Started by Bodger, September 01, 2008, 09:25:01 PM

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Bodger

I've read through the archives and didn't really find any answer.  I know the tech line will be open tomorrow also, so I can call them.  However I thought I would bring this up here.  My up down motor on a 95HD40 (Onan 24) is giving me a problem.  It runs fine at the beginning of the day but soon starts dragging on the way up (of course).  I've cleaned and lubed the posts and greased the bearing at the gear box, checked the oil in the gear box, greased and checke the up down switch (it was replaced last year). None of that helped so I put in the reserve motor with new brushes.  The brushes on the pulled motor looked ok but I replaced it anyway.  When the belt is off it seems to run fine...putting a volt meter on the alternator reads 14v and when I hit the up switch it drops to 13 or 12v.  Over the years I have thought about replacing the stock motor with a larger one...I've had the mill since it was new so it must not bother me too much but sometimes it seems to be a real bottle neck.  Any ideas about how to troubleshoot this?  Thanks in advance.
Work's fine for killing time but it's a shaky way to make a living.

Tom

Keep in mind that it might not be changing speed, it could be that you get in a groove and want it to go faster.  I've done that many a time.  Experience and practice make us operate a lot faster.

One thing it might be is the contacts on the drum switch.

It also might be that the battery isn't getting enough time to be charged.  Even when the alternator is putting out, if you shut the engine down too much, the battery never gets topped off and the power drops.

That might have something to do with it getting slower as the day goes on.

The tower pads might be dragging.  You have to be careful about using oil on the tower or the sawdust builds under the leather pads.  The dryer they run the better. 

The up/down chain might be binding.  I doubt that's it or it would be slow all of the time.

The other thing that causes irratic speeds is brushes.  But, you said they are new.  Are they seating good?

Hydraulics use a lot of battery.  That will also run the battery down.  Unless you are going to leave the mill unattended for a half hour or more, I would leave it running. :)

backwoods sawyer

Try cleaning the groves in the armature, as they will build up with dust from the brushes and cause a loss of power. As the belt warms up, it could be slipping more. I went to a larger pulley on the motor and increased the up down speed on mine as it seemed a bit slow as well. Check your gearbox for play at the input and output shafts, I had to replace mine and it was only 4 years old at the time.

Let us know what you find out.
Backwoods Custom Milling Inc.
100% portable. . Oregons largest portable sawmill service, serving all of Oregon, from our Backwoods to yours..sawing since 1991

jpgreen

I would add to all the info above by saying Piney Woods has a great spring assist mod that increases the speed on the up.  I going to install that on my LT40.
-95 Wood-Mizer LT40HD 27 Hp Kawasaki water cooled engine-

jpgreen

Quote from: backwoods sawyer on September 02, 2008, 01:02:14 AM
Try cleaning the groves in the armature, as they will build up with dust from the brushes and cause a loss of power. As the belt warms up, it could be slipping more. I went to a larger pulley on the motor and increased the up down speed on mine as it seemed a bit slow as well. Check your gearbox for play at the input and output shafts, I had to replace mine and it was only 4 years old at the time.

Let us know what you find out.


Backwoods... curious on the pulley change.  How much faster was it, and did it seem to have enough torque?  What sized pulley did you step up to?
-95 Wood-Mizer LT40HD 27 Hp Kawasaki water cooled engine-

MartyParsons

Check mast pads top at top of head travel thickness of a credit card on one pad, bottom pads at bottom of head travel, check for binding in gear box, idler bearings and chain tension, check ground at rear of operator station and every other areas, battery engine etc. Crucit breaker weak? Battery voltage and amp draw during up movement. I am not sure of the spec. amp. drum switch contacts and the positive connections.
Tom covered some of these.
Marty
"A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty." -Winston Churchill

Bodger

did anybody guess up down gear box?  I checked the motor(s) and they seemed ok...getting power from the box.  Tech support at WM said check the gear box..it had one bad bearing.  You couldn't really feel it, but when the pressure of pulling up put it in a bind I guess that was enough to slow things down.  Now I still haven't put it back on the mill. I knocked off a little early to run to town and get the bearing. (Granddaddy always said he only wanted a half a days work from us boys...what we did with the other 12 hours was up to us) The gear box from WM was around $300..the two replacement bearings from NAPA less than $10.  Getting the mill back up to speed will be priceless.  Thanks for the help...If by chance this doesn't fix it I will be back.
Work's fine for killing time but it's a shaky way to make a living.

backwoods sawyer

Quote from: backwoods sawyer on September 02, 2008, 01:02:14 AM
Check your gearbox for play at the input and output shafts, I had to replace mine and it was only 4 years old at the time.

Let us know what you find out.

Backwoods Custom Milling Inc.
100% portable. . Oregons largest portable sawmill service, serving all of Oregon, from our Backwoods to yours..sawing since 1991

Bodger

Both shafts run on bearings.  I would guess that running them for extended time with a bad bearing could cause a problem in the pinion gear setup that changes the direction of the power.  I pulled it all down and replaced the bearings, checked the gears and put it back filled it w/gear oil.  Put it back in this morning and boy howdy, great speed on the way up.   It's amazing how things go bad little by little over a period of time and I seem to not notice.  thanks for all the input and help. 
Work's fine for killing time but it's a shaky way to make a living.

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