New Tablesaw woes... smokin' motor issues

[Chad Helme]

Hey guys. First of all, I want to say hello, and let you all know how excited I am that I found this forum! I have been thinking for a bit now about joining an online community to feed my new love for woodworking projects with knowledge. Just so happens that I'm here out of necessity for the moment, but I'm sure I'll be around quite a bit now that I know you all are hangin' out in here and talking about such great stuff!!!

So here's my issue. Got my hands on a table saw from craigslist. Craftsman model# 315.228510 Super psyched to grab this baby. Its huge compared to my little plastic Ryobi job site saw. Has a nice big steel top and a long and straight Align-a-rip fence. I love it. Its a nice ride compared to where I'm commin' from. But, 3 minutes into using it, the motor is smoking!

After shutting it off and regrouping, I tried again, and after a couple minutes, its smoking again. Then we realized, its one of the capacitors (has two bolted to the outside). Popped it out to have a look and sure enough, the platic housing was starting to melt and deform on the capacitor itself.

So now I'm on the quest to find out what I can about this capacitor,and the motor it came from, and if its even the right capacitor for the motor. The motor itself doesn't have a lot of information on it. Has the Part number as TH0112/TH0208. This doesn't produce much results through craftsman's website (or google for that matter), so I'm wondering if it is a replacement motor? I don't know a whole lot about capacitors either. I think I can probably find a similar capacitor, but the mystery surrounding the whole issue has me wondering if the capacitor may have been swapped too, possibly the reason the thing is smoking in the first place?

Can anyone help?

[David Gilbert]

I'd suggest that you go to OWWM.org, ask your questions, and search for information. Old Woodworking Machines dot org is a great resource for information about our machines and such.

[Chip Lindley]

Chad, disconnect the capacitor and take it to any electric motor shop. They will provide you with one just like it. Write down the info off the motor plate so they can verify exactly what motor the capacitor fits. This should be an easy FIX!

If the motor is not Craftsman brand, the saw has been retro-fitted with another motor. There is nothing special about Craftsman motors. The original motor could have *gone south* or the previous owner could have put on a more powerful motor.

Check that the motor is not *accidentally* a 230v motor you are trying to run on 115v. (doubt if it would run anyhow) IF indeed it is a 115v motor, see that its Amp rating on 115v is not exceeding your wiring circuit.

We are interested to read what you find out! Good Luck!

[Dan Friedrichs]

Welcome to the Creek, Chad.

The capacitors typically mounted on the sides of induction motors contain a wet electrolyte that will, over time, dry out and cause the capacitor to fail like this. Rather than looking at the motor, take a look at what's left of the capacitor. Does it have any values printed on it? Basically, you just need to find a replacement with the same capacity and voltage rating, and you should be good.

If the capacitor contains no helpful printing on it, just take the entire motor to a motor shop - they'll easily be able to grab something that should work for you. The value of the capacitor needs to be close, but it's not even remotely critical. Chances are, if you find one that physically fits in the same space, and is rated for a few hundred volts, it will work fine.

[Chad Helme]

Great.

Thanks for the info guys. I've got another, much older craftsman that won't spin on its own. I'm starting to think that the cap is gone in that one too.

[Don Jarvie]

If the motor is original or you think it may be original you can enter the table saw model number 315.xxxx at Searsparts Driect and the motor may be listed. If so the capacitor will be listed in the parts diagram.

If all else fails you can probably pick up a replacement motor of CL for short money and just replace the motor.

Good Luck

[Mike Cruz]

Just my 2 cents, but, not knowing a lot about motors, but knowing a LOT about how a LOT of Harry Homeowners operate: The reason that this motor, if indeed it is not original to the saw, is having problems is that all too often H.H.'s run equipment on extension cords that are WAY too long and WAY too small a gauge.

For those out there who know about motors: Could a blown capacitor be the signs of a motor that has been mistreated like I just described above? If so, replacing the entire motor might be your safest bet, Chad. Just the peace of mind that a new capacitor on a possibly shot motor won't start smokin' again would be enough for me.

Again, just my motor-ignorant 2 cents...

[Thomas S Stockton]

Chad
Follow Chip's advice and you should be good to go. Capacitors are fairly interchangeable so a motor shop will get you one that works even if the specs are slightly off. As another poster said check to make sure it is wired correctly. A third problem could be the centrifigul starter sticking, but the time I had that problem it tripped the breaker.
Tom

[Chad Helme]

Well again, I sincerely thank everyone for thier .02 cents worth. I'm pretty sure the actual motor is fine. It started strong (snapped right to life), ran and cut fine, even after it started smoking (about 2-3 minutes in every time). Seemed like, if I didn't care about a little smoke, I could have kept on with my project. We actually tried starting it after removing the capacitor and then we blew a 15-amp fuse (yes, fuses in my house, not breakers).

I do know the "over loaded" power cord all too well. I work for a custom home builder here in the beautiful state of NH. We build gorgeous, energy efficient, custom homes, often on top of a mountain or something. We usually run the entire job site off several hundred feet of extension cord and deal with those issues all the time. But that was certainly not the case on the day in question in my garage.

My other issue, being that I leave the house at 6:15am and get home around 5:15pm is catching someone during their shop hours. I got a recomendation for a local shop and tried emailing them. Figured I would explain the symptoms, get their professional opinion, and find out when I could come by. But the email address (which I got off their web page) came back, undeliverable. So back to the drawing board on that one.

I wish there was more info on the motor it self. Literally, there is only the PN:TH0112/TH0208 and the serial number. Not even the HP rating. I have another, older craftsman (doesn't run either!!!), but that one has every spec imaginable stamped right on it. Leads me to belive this is not the original motor (but I suppose anything is possible). If I could find info on the web about the motor itself, I might just find a replacement cap online and replace the thing.

[Dick Strauss]

Chad,
The capacitor isn't the issue if the motor comes up to full speed. I would replace the capacitor anyway since you said it has physical damage.

Did you try blowing out the motor with a compressor?

Since it will run for a few minutes I think the centrifugal switch might be jammed with sawdust (or arced closed worst case). If the switch is staying engaged too long, the capacitor will overheat since caps are only designed to be active for a few seconds to get the motor up to speed. The capacitor adds out of phase electricity to the circuit which helps the motor come up to speed while also flattening the start up current demands of the motor. But, if the cap stays engaged too long, it will cause a drag to the motor once it is up to full speed IIRC.

[Lee Schierer]

On many craftsman saws on each end of the motor are small plastic plugs for oiling the beairngs. Most guys don't even know they are there or what they are for. You need to remove the plugs and put a few drops of oil in these holes once or twice a year.

I did enter your model number on the Sears parts web site and they list a motor for that saw @ $185, but don't give the specs and don't show a capacitor on it.


You'll want to replace the die cast pullies and belt with machined pullies and a link belt. Also do a careful saw alignment and the saw will cut much better.

[Rod Sheridan]

Chad, I have no specific knowledge of your machine, however many Craftsman tablesaws had the start winding disconnected by a current sensing relay in the on/off switch box.

The cute thing about the current sensing relay is that it only operated in one position, so if you had the switch upside down, or the relay armature was dirty, the saw ran with the start winding engaged all the time.

That tended to "Let the smoke out" of the motor.

If you have one of the saws with those plastic switch boxes, unplug the saw and open the box to see if this could be the case.

Regards, Rod.

P.S. I went on line and checked the parts list for your saw, it doesn't have the current sensing relay so ignore the above.

I suggest that you take the motor apart and clean the centrifugal switch, since your starting winding and capacitor are working. (You posted that without the cap, the motor opened the branch fuse, so your start winding and cap are OK)>

Your start start switch is staying closed, probably due to saw dust jamming the centrifugal actuator.

Regards, Rod.

[Chad Helme]

Okay, thanks again for everyone's brainstorming and shared experiences. I like this new "centrifugal actuator" theory. I'm gonna see about getting that cleaned out. Might be tricky, cause the screws are really soft and I stopped the last time I tried to remove them. Then all I have to do is figure out what I'm looking for in there.

On a different note, in an effort to get at least one of my saws working, my retired father has taken home the motor to my other, older craftsman tablesaw. That one simply wouldn't turn it self over. He says now, that if he gives it some help at startup, it will run. So does that one probably need a capacitor?

[Gary Lange]

Chad Here is a copy of the Owners Manual. It appears that someone changed the motor because they don't mention capacitors in the parts list. You may want to print this out and save it or just download it to your computer. I printed on out for a Craftsman tool I had and it comes in handy.

http://disruptit.com/manualgateway.cfm?pdfwanting=43988&username=anon&AV=123345&I=24.32.64.150

[Chad Helme]

Thanks a bunch Gary. That'll help a lot.

[Mike Henderson]

On a different note, in an effort to get at least one of my saws working, my retired father has taken home the motor to my other, older craftsman tablesaw. That one simply wouldn't turn it self over. He says now, that if he gives it some help at startup, it will run. So does that one probably need a capacitor?
That's the first thing I'd try.

Mike

[Chad Helme]

Well thanks for everyone's tips and ideas. I've been to my local Grainger. They sold me a capacitor for my older table saw motor, which now runs fine and I am at least opperational for the moment.

As for my newer craigslist aquisition, it is still a boat anchor for now. I have opened up the motor, and fiddled with what I believe is the cetrifugal actuator switch (a couple "blade like" contacts attached to springs and mounted on the main drive shaft). It seems to be moving freely. Spray'd some wind and some cleaner in there to make sure. Put it all back together and fired it up with the old Capacitor wired in. Fired right up, ran strong, and this time the Capacitor started smoking almost immediately. Shut it off quickly.

Grainger did not have a Capacitor for that motor. At least one that would fit in the cylindrical, stamped housing that bolts to the side of the motor and holds the capacitor. They had one that would work with similar specs, but the physical size was much bigger. They suggested that I go to a local motor shop to find the odd sized capacitor. Luckily, I got out of work early last Friday, and did just that. They told me that the only capacitors they had, would be the same as Graingers, and that it appeared that mine was a Japanese Capacitor, probably from a Japanese motor. They said they could bolt a new housing to the side of the motor to fit one of their bigger capacitors if I bring the motor in. I'm gonna have one more go at finding the exact replacement online and see if a new cap solves the problem before bringing it in to the motor shop.

I'll update later after that mission plays out. Thanks again.