Thickness Sander Troubleshooting

[Patrick LaFree]

Merry Christmas!

This year for Christmas I bought myself a new conveyor belt motor for my thickness sander. My old one finally burned up and I bought a Dayton DC model recommended by the manufacturer. (DC Gearmotor 90VDC, Nameplate RPM: 21, Max. Torque: 50.0 in.-lb., Enclosure: TENV) I finally got around to hooking it up and cannot get it to run. I am getting power to both leads but nothing out of the motor. I am beginning to wonder if it was never a problem with the motor but rather something upstream like the variable speed control or the inverter.

Does anyone have any experience or advice in replacing one of these? Maybe I am not getting enough juice to the motor? Its reading hot with a tester but I do not have a multimeter or the knowledge on testing with them to understand the problem.

Any advice would be greatly appreciated. Every time this machine breaks down I start shopping for a new one but I havent found a comparable model that I like. I use it mostly for taking door parts down to final thickness and the newer machines all seem to be drum sanders or large and expensive timesaver styled machines.

Thanks again!

Patrick

[Patrick LaFree]

Also, my machine is a Woodtek CT-1332C 13" Belt Sander. I have not figured out how to upload photos to this site using Chrome so I apologize is my post is a bit vague.

[Matt Day]

You need to be a Contributor ($6/yr) to post pics.

[Dan Friedrichs]

By "tester" do you mean a test light?

Is it possible the conveyor belt mechanism is bound up and the mechanical load too much? Have you tried disconnecting the motor drive shaft and just seeing if it will run without a mechanical load?

[Richard Coers]

So now you really don't even know if the old motor was the problem. You should take the sander to a motor repair shop, or find a machine repairman in your area. If you don't know anything about a multimeter or how to read one, the only other option would be to replace every electrical component in the conveyor control.

[Dick Strauss]

My buddy has a Ryobi 1632 sander that has done the same thing twice. Each time it was an issue with the potentiometer going bad. The last time he couldn't find the spares I ordered the first time so we reversed the terminals on the potentiometer (the potentiometer or pot has three terminals but only two of which get used with the center tap being a common). If you reverse the connections where you leave the middle common tap and change the outside wire to the opposite tap, your motor might work again but you will have to turn the speed control knob/pot the opposite way to increase speed, etc. If it works when you reverse connections then you know the pot is bad and you can either use it reversed or buy another pot to replace the existing one to get it to run correctly.

I would suggest you order a better quality pot if you replace it. They make mil-spec ones that are much more reliable.

[Patrick LaFree]

Thank you for the advice!

The problem is not with the belt. The last time it went out it was a problem with the gear box on the motor and I had to replace several gear shaft pins so I've eliminated that as the culprit.

I am thinking that it is in fact a problem with the potentiometer. The conveyor used to work without the belt running but about a year ago it started working only when the belt was running. Strange but it still works. It is just odd to me that it would still send power to the motor but not enough to power the motor.

I will look in to replacing it or changing around the wires / direction.

Thanks again for the advice!

[Patrick LaFree]

Hi all,

I finally got squared up with a donation so I can post pictures. Hopefully that will help shed some light on my set up.

IMG_20191225_143212.jpg
Its a great little machine that has been long discontinued so the parts for it are getting harder to find.

IMG_20191225_143155.jpg
This is the new motor I bought that drives the conveyor. Currently I cannot get the output shaft to spin at all. As I said im getting current through the two leads going into the motor but no movement. This leads me to believe the problem may be with the rheostat switch.

IMG_20191225_143204.jpg
This is the mess of wiring in the switch box. I cannot tell if the problem is with the Rheostat, the ac/dc inverter that feeds it, or the circuit black circuit board that feeds everything.

Thanks again for your help. I am thinking about just loading it up and taking it to someone who knows what they are doing before I ruin anything but I keep thinking its a simple thing im missing that someone here might be able to point out.

Patrick

[Dan Friedrichs]

Patrick, in that box I see a fuse, a current meter, some start/stop buttons, a transformer (although I'm not sure what it's for), a rheostat, and a magnetic starter+overload (the black thing). I don't see any ac/dc inverter, or any other "circuit board".

I think you mentioned that the replacement motor is a DC motor. Are you sure that's correct? It's possible that such a brushed DC motor is actually a "universal motor" (like a router or shop vac), which can be run on either AC or DC, but not all brushed DC motors are universal , and I don't see any means to get DC from what's inside that box...

[Richard Coers]

You know the gearbox is free to spin? Gearbox trouble once could just as easily be gearbox trouble twice. If you can spin the gears freely, then fine. If not, take the motor off and see if it spins on it's own.

[Patrick LaFree]

Thank you for your reply's.

I took the motor off and checked it with a 18v battery and found that it does in fact work.

I believe the problem is somewhere in the rheostat, the transformer, or the magnetic starter/overload as Dan pointed out. I am not sure what that device does. It has a button on it that says ARC reset that ive pushed but im not sure what changed.

I tested the leads going to the conveyor belt motor and only got a 3.5ish volt reading if im reading it correctly. Is it possible the motor isnt running because the current is simply too weak? If so that leads me to believe the problem is in the Rheostat. I was planning on swapping the leads on the Rheostat as Dick Strauss suggested but all 3 leads coming out of the Rheostat are hooked up so im not sure which one is neutral/positive/negative. Im trying to isolate the problem before I take more things apart.
IMG_20191229_074117.jpg

Thanks again for your responses!

Heres my shop helper for the day as well!
00100lrPORTRAIT_00100_BURST20191228141328347_COVER.jpg

[Dan Friedrichs]

Try measuring AC voltage on those wires to the motor. Your meter is set to measure DC volts, and as I mentioned above, there doesn't appear to be anything that converts AC to DC in that machine.

[Patrick LaFree]

Thanks Dan,

I took your advice and measured the AC current and got ~21v
IMG_20191229_091954.jpg

Its very strange that it would have any AC current as I bought the motor that was recommended by Woodtek.

I am thinking about bypassing the confusing wiring in the unit itself and buying a variable speed control to power the conveyor independently. Thoughts?
https://www.amazon.com/gp/product/B0...Z366MFVO&psc=1

The main 3hp motor that powers the drum sander works great so im hesitant to start messing with the magnetic starter/overload board.

Thanks again!

[Jon Heithold]

Patrick--
have you ever had to replace the screw bushings on the main threaded rod? my 25" needs them and don't want to tear into it until I have some guidance, thanks, Jon, Lincoln, NE