Power feed problem with LT35

WV Sawmiller · April 21, 2025, 09:21:55 AM

The last job I did 2 days ago I started having power feed problems on a big log/wide cant. The mill was slightly angled and I was cutting a little uphill till I finished the log and re-leveled it. The cuts were 20-22 inches wide. I had to slow to a crawl with new/resharpened blades and it would still trip off. After I finished the cant, re-leveled the mill and got a normal sized log (think 12" or less width of cut) it did much better but would still trip once in a while then it got to just stopping but not tripping the breaker. I could back up a few inches and re-start. It did not do it at the same spot like a bad spot on the chain or feed rail somewhere. Just at dark I loaded a little 12-13 inch poplar log and could not get the mill to cut more than a few inches at a time so I quit thinking I had a bad bearing.

I brought the mill home and checked the rollers. They spin freely with the weight lifted off them. I checked the cam follower bearing that the chain runs over and it seems to roll normally. Same with the other CFB that runs against the bottom rail (And holds the whole head on the trailer - but we don't want to talk about how I found that out).

I called WM and got hold of Bob in electrical support and tested a few items. I could set the power feed on a slow speed and lock it forward and it would travel 10-12 feet then stop so he had me tap the motor and even the little speed controller knob to see if that unlocked anything. Neither had any effect. The mill would travel freely in reverse if that is any indicator.

I have about 1400 hours on that motor so I ordered another and will install that. I will check and may replace the brushes in this motor and keep it as a spare if I don't see any other indicator of trouble in it.

If anyone has ever had similar problems with the power feed on an LT35 and has any suggested troubleshooting tips to check I would love to her them. My big concern is if I replace the motor and it works I still would be confident till I run through a real big heavy log or two. I hate an intermittent problem!

Magicman · April 21, 2025, 09:57:39 AM

Breakers are not designed for multiple trip operations. They will gradually loose their ability to hold, so you might have a "tired" breaker problem.

To troubleshoot, in addition to a VOM, you also need a clamp on Ammeter to tell you the current draw. Without one, you are guessing and throwing parts and $$ at a problem.

Old Greenhorn · April 21, 2025, 10:04:30 AM

Howard, you don't say, but did you check the belt tension? The head stopping but breaker not tripping kind of leads me to wonder if the motor is turning but the head is not moving. Probably you did check it, but I thought I'd ask.

SawyerTed · April 21, 2025, 10:17:19 AM

I went through something similar with the LT35. After several parts replaced based on advice from WM and here, I checked the brushes.

It was brushes. Checking them only costs time. If it's not that, at least you will know.

WV Sawmiller · April 21, 2025, 11:32:51 AM

Lynn,

I know you are right but I am a very poor electrician and likely not being very methodical in this. I don't have an ammeter and am only vaguely somewhat familiar with their use and looks like I'd need 2 people to check this as the mill is running and the head is moving under a load.

Tom,

Excellent question and I checked early on and should have mentioned the belt tension looks good and the belt is in good shape.

It is always good to make sure someone (especially me) is not overlooking what should be obvious. (Kind of like the time I had a chainsaw locked up and thought I had a seized engine. Turned out I just had the chain lock engaged.

)

Ted,

Based on the hours of use both Bob and I suspect the brushes are the most likely cause and simply replacing them would likely fix the problem. If so, the new motor will fix the problem and replacing the brushes in the old one would give me a working spare. If it is not the brushes now it would hve been soon.

WV Sawmiller · Reply #5 - Re: Power feed problem with LT35

Well the UPS guy dropped off my replacement power feed motor midafternoon so I went out and ran the head to the rear, unhooked the feed chain and removed the link to take the adjustment bolt/hook off and pulled the chain through the feed system. Then I loosened 5-6 bolts and remove the bracket holding the motor, unhooked the leads and hooked them to the new motor so I kept the connections the same and not run the motor backwards anything.

I like to do this kind of work where the chain has to be removed with the head at the rear of the mill as I find it easier to access and replace the chain at that end. The hydraulic box and such get in the way if working such from the front of the mill.

While doing this I spotted a bare spot on one of the leads where the insulation had worn off. Of curse a bare wire could could never bump against the frame while traveling and if it did I am sure it would not do anything funky like tripping a breaker or causing erratic performance.

I repaired the bare spot and hooked the new motor up and tightened it in the frame, replaced the pulley on the shaft and reinstalled the bracket. I don't know where that extra washer came from but I am sure I did not really need it either.

Feeding the chain back over the CFB and under the sprocket was a little tedious but I got that done and tolling the pulley pulled the rest of the chain through. I replace the link and tightened the chain back to it's previous position. I adjusted the little pulley on the motor to line it up with the larger pulley and everything seems about ready. I need one more bolt to go in the motor to replace one that has broke off in the old motor a long time ago. I'll get that in the morning I guess and put the small covers back on and will be ready to saw again. I'm keeping my fingers crossed this solves the problem.

The bare wire could have been the problem all along but I don't think it was the major issue. The motor had high hours and I don't feel bad about replacing it now and I'll check and likely replace the brushes and keep it as a spare.