# Is this a symptom of my motor going out on my table saw?



## JarodMorris (Nov 24, 2011)

When I flip my table saw on, it runs very slow and never speeds up, then trips my circuit breaker. I feel it and the motor is not even warm to the touch. If I remember correctly, a motor that draws too many amps (i.e., trips the circuit breaker) is getting old and is about to burn up or quit completely. Thoughts on this? Fixes? This is an old craftsman that my father-in-law gave me almost 10 years ago and it was rather "experienced" at the time he gave it to me.

Thanks for the help. I'm a lot smarter woodworker because of all of you that let me borrow your thinking caps every now and then. I really appreciate it.

jarod


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## JustJoe (Oct 26, 2012)

No easy answer, just a few more questions for you to get you going: Is there a vent on the end of it, and if so have you tried blowing out all the years accumulations of sawdust out of it? What happens when you plug it into another outlet, one with nothing else running on the circuit? Does it have a starting or running capacitor that might be going bad? Does it run with no load (when you disconnect the belt/chain or whatever is making it drive the tablesaw)?


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## TomFran (Jun 19, 2007)

If your saw is a belt driven model (which an older Craftsman should be), I would would take the belt off the motor and turn it on. Bad arbor bearings could cause a motor to bind, but if you remove the belt, that will eliminate that possibility.

If it is slow starting without the belt on, it's a motor issure OR I suppose it could be a *bad capacitor*, The capacitor stores energy, and then lets it go when you first start the saw. The capacitor's job is to get the blade going, so the motor doesn't draw a lot of amperage, which will trip the breaker. It does sound like it could be only your capacitor, and that's way cheaper than a new motor.


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## JarodMorris (Nov 24, 2011)

Thank you for the replies. I have plugged it into different outlets and it does the same thing. I'll go blow it out as best I can and see how much dust there was. Any links to how to test a capacitor? If I understand, the capacitor is actually on the outside of the motor, usually under a dome-like piece of metal with 2 screws holding the cover on. Is that right?

Jarod


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## TomFran (Jun 19, 2007)

"If I understand, the capacitor is actually on the outside of the motor, usually under a dome-like piece of metal with 2 screws holding the cover on. Is that right?"

Jarod,

That is correct.

From the description you've given of the problem. It really does sound like a bad capacitor. Take it out, and buy another one by matching it up. Then, install it and see if that doesn't fix your problem. You should be able to return it for your money, if not.

A word of caution on handling capacitors though. A properly functioning one stores a charge that will shock you, if you touch both connectors at once.


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## JarodMorris (Nov 24, 2011)

Tom,

Thanks for the warning. I recently had to do a little work on our microwave and that was the advice my father gave me from his time spent owning an appliance repair business. He said the ones in microwaves have enough juice left to do some serious damage. Maybe this one isn't as powerful, but I'm not going to take my chances. That's my #1 rule in woodworking. Don't. Take. Chances.

What kind of store has replacement capacitors? Surely the box stores don't have them, do they?

Jarod


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## wlkjr (Mar 12, 2013)

I usually find good deals on capacitors on Ebay.


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## Loren (May 30, 2008)

Capacitor is a likely culprit in any single phase induction
motor acting weird.

If you have a local motor shop, take it down there and 
they can test and replace the capacitor for probably
about $20. While capacitors are not costly, they are
not so cheap they are worth replacing as a way to 
test whether or not the old one is bad. You can
test yours with a meter, but if you're not familiar 
and/or don't have a friend who understands how 
to use a meter, going to a convenient motor shop 
a good solution.


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## shawnmasterson (Jan 24, 2013)

if it's not the capacitor it maybe the start contact switch inside motor sticking.


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## gfadvm (Jan 13, 2011)

It was the start contact switch inside my 2 hp 220 that kept it from starting. Motor shop fixed it quickly and inexpensively.


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## woodbutcherbynight (Oct 21, 2011)

Quick test for your capacitor, take off the belt, Again *TAKE OFF THE BELT*. Hit the start switch and spin the MOTOR some, careful not to get your hand wrapped up.. If the motor winds up and starts running at speed the start capacitor is bad, if not the motor is bad replace it. Grainger can get them and they are usually about $5-10. They can be tested but you need a meter set for uF to do so, most do not have this ability. Be sure to read the capacitor and get the exact same thing when you replace it, it matters alot. Somewhere on the case is printied what you need. i.e. 25uF +/- 5% 250VAC. Had two things go bad with capacitors this year, the furnace fan and the mini lathe. Go figure 30 years and never even had to bother then two in a few months. (laughing)


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## JarodMorris (Nov 24, 2011)

I went and checked my meter. Not a surprise but it doesn't have the uF capability. I'll take the belt off tomorrow and start it up. Worst case scenario would be that I take the motor off of my porter cable air compressor that has other issues (on the To Fix list but never gotten around to it). I can handle a broken tool. I don't want to have 2 broken tools when I could have at least 1 going.

jarod


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## runswithscissors (Nov 8, 2012)

If you try a replacement capacitor and it doesn't fix the problem, I doubt if you'll be able to return the new one. Most places won't accept returns on electricals. I ordered a replacement switch for a PC 690 D-handle router, used the correct catalog number, and they sent the wrong one. No, absolutely not, they said, when I asked about returning it.


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## gfadvm (Jan 13, 2011)

woodbutcherbynight- my motor would start and run if you spun it like you described. I replaced the start capacitor and it did NOT fix it. Took it to the motor shop and they said contacts inside the motor was the problem.


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## Tomj (Nov 18, 2011)

My radial arm saw motor was doing the same thing, (not speeding up and trip the circuit breaker) so I changed the circuit breaker and switched it from a 15 amp circuit to a 20 amp circuit and it worked. I also clean the dust out of the back. After a while of running on the 20 amp circuit I then swithed it back to the 15 amp circuit and it worked fine. It seems the bearings or gears were a little stuck and running the combination of what I did freed them up. Anyway, I hope you figure out the problem.


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## RonInOhio (Jul 23, 2010)

If it turns out to be the brushes then replace both of them. Even if one looks good.
Then after the new brushes are installed, on initial start up run the saw free with no 
load/no sawing for about 5 minutes. This sets the brushes
and they will last longer.
My guesses are your problem is one of these things.

Dust or a critter inside the saw switch box.
Start cap
Bad switch 
Bad brushes on motor.

You didn't say anything about how long the saw sat without running or how cold it was, but either way its likely one of the above and is fixable.


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## runswithscissors (Nov 8, 2012)

If it's a universal motor (which some light duty bench top saws have), then it will have brushes. But if it's an induction motor, there are no brushes.


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## JarodMorris (Nov 24, 2011)

This is not a universal motor or a bench top saw. It's a craftsman contractor's saw. My wife has me busy making a raised bed for a garden this year so I haven't been able to work on it. It's been horrible. In the shop working on other stuff, seeing the motor there ready for me to go work on it and NO TIME. It's like a steak in front of a dog that he can't eat. She doesn't know what she's doing to me!

jarod


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## devann (Jan 11, 2011)

Jarod, I had a similar issue with my chop saw. I thought it was the brushes but it turned out to be the brushholder.


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## woodbutcherbynight (Oct 21, 2011)

gfadvm did it spin fast as in up to speed? I yaked at a electrician today and through this by him. He suggested the capacitor was bad BUT then tells me they can burn out due to poor contacts. All these secrets…... Sucks you had to take it to the shop. He did tell me to replace the capacitor if any motor work was done. Lovely huh?


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## Tennessee (Jul 8, 2011)

This is a capacitance start, induction run motor. Very common on these types of saws. The saw motor, if full of dust, will lose its ability to engage the start/run switch, which is a centrifical switch which switches from start windings with the capacitor in series to boost rotation, to the run windings, a straight set of induction motor windings.
I would first:
Clean the start/run switch with non-plastic corrosive contact cleaner , cleaner not harmful to plastics, and compressed air. Make sure that the switch is making contact for the start windings, check by noting if windings are engaged by the motor trying to turn in the proper direction.
Next up would be the load, by removing the load after cleaning and see if the motor runs normally. That means removing the belt and no-load starting the motor.
If not, the cap replacement is next up.
If cap replacement fails, there is a fair chance the start windings are bad, but I doubt you will get this far.


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## gfadvm (Jan 13, 2011)

Mine would run fullspeed and cut nornally AFTER you gave the blade a spin to get it started. If you didn't spin the blade, it made a LOUD humming and then tripped the reset on the saw.


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## runswithscissors (Nov 8, 2012)

I put a Sears motor on a Delta contractor saw I used to have. It would refuse to start sometimes, so I'd have to partially disassemble it (not too extensively) and clean the crumb of sawdust from between the starter contacts. Happened fairly often.

All of which is an argument for TEFC (totally enclosed fan cooled) motors on equipment that makes a lot of dust. That's what those motors are for.


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## vernacular (Aug 20, 2010)

Wait what model is it? I just had that happen and it was a 12 buck fix, (2 hours of easy labor as well) to replace a rear bearing on the the motor drive shaft. My saw runs like a beast again. It did the same thing, cut a really tough piece of walnut and then nothing. Got it apart and found the rear bearing ceased and completely smoked out.


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## woodbutcherbynight (Oct 21, 2011)

runswithscissors +1 TEFC motors are what we need for the environment we work them in. Cost as always is the issue. When I finally bother to change my 110 vt TS motor I expect to pay some more for a 220vt TEFC. That said until the motor dies now forget it. (laughing)


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## hotbyte (Apr 3, 2010)

Several years back my TS motor was acting the same. Tried a new capacitor, cleaned start contacts, etc. to no avail. Finally just bit bullet and ordered replacement motor from Grizzly. I went with a 1HP TEFC. Started to upgrade to 1-1/2 HP but was worried about extra weight and size of motor at 45 degrees hanging off back of contractor saw. When tilted to 45 degrees, there is barely clearance between motor and saw top. I had put up with the slow start for a while and the "instant on" of the new motor has been wonderful!


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## RussellAP (Feb 21, 2012)

Havent read the other comments and I'm sure someone already has this pegged, but it's likely there is sawdust in the centrifugal switch and it can't switch from start to run. Start windings on TS can pull over 20 amps real quick. You need to consult the manual and hope its an older model. Some of these new motors are epoxied together.


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## Grandpa (Jan 28, 2011)

Look in the back of the owner's manual and there shoulf be a trouble shooting chart. Check that out. Fixed my old craftsman


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## MedicKen (Dec 2, 2008)

If the saw is old enough to blow the cap you might consider a bearing change as well. Sealed bearings are only good for about 20-25 years. The grease is probably more like a hard crusty mass by now and not doing much for lubrication. Bearings are cheap and easily replaced.


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## JarodMorris (Nov 24, 2011)

I just went out and took the belt off the motor and started it up with no load on it at all. It starts up and gets to speed just fine under no load. I an also hear what I think are is the centrifugal switch operating. When I put the belt back on to the motor, it's a no go. I have sprayed WD-40 on the bearings, centrifugal switch, and nothing. An electrician friend of mine is going to bring his meter over this weekend to test the cap and see if it is bad. I have found one on the sears website with exact same model number for this motor. Thankfully Sears sold so many of these table saws that maintaining parts for them is still profitable and worth their time.


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## JarodMorris (Nov 24, 2011)

I went ahead and replaced the capacitor and that didn't do it. I'm now looking for 1) a place to repair the motor or 2) a new table saw. I've been looking on CL around here and the selection of what I want is slim at best.


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## JBurt (Apr 19, 2013)

I know it's a long shot here but did you ever resolve your issue? I've got the same thing on my 70 year old craftsman TS.


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## MrUnix (May 18, 2012)

> I know it s a long shot here but did you ever resolve your issue? I ve got the same thing on my 70 year old craftsman TS.
> - JBurt


Sure hope he did… it's been almost three years, which should have been plenty of time 

Cheers,
Brad


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## ottox1 (Feb 14, 2016)

My old Craftsman table saw was doing the same thing a few years ago. Turns out the end bearings (actually bushings) were in bad need of oil. There was a little plastic cap plug at each end of the motor above the bushings. I pulled the caps off and applied a few drops of handy oil to each one and rotated the motor by hand until it worked its way in to the bushings. It's worked fine since then but I do put a few drops of oil in each bushing from time to time. Don't over-due it with the oil.


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## JarodMorris (Nov 24, 2011)

I didn't fix the motor. I replaced the motor with a motor from Harbor Freight and it's worked great for years. Now I'm having similar issues with the motor on my compressor but I have a 2hp spare I hope I can make work. I'm afraid it may be underpowered. Then again, maybe the motor on it now is not original and it too is underpowered and that's the source of my problems. Too many problems to fix with such little time.


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## MrUnix (May 18, 2012)

There is very little that can go wrong on an induction motor, and with proper maintenance, they can last virtually forever. They don't just go bad or 'burn up'. Problem is, very few people do any kind of maintenance on them and just run them until something fails catastrophically. Bearings (bushings), capacitors and the centrifugal switch are all maintenance items that need to be checked and or replaced every so often. For a three phase motor, just the bearings. Many times, a motor that appears to be failing simply needs to be opened up, given a good cleaning and possible new bearings to bring it back to like new. Capacitors can be checked with a cheap multimeter in resistance mode and are inexpensive to replace. There is no need to go out and spend a hundred bucks or more for a new motor when 99.9% of the time they can be fixed for under $20 and a little effort.

Cheers,
Brad


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## JarodMorris (Nov 24, 2011)

I have checked the capacitors and they were fine. I'll YouTube the other things you mentioned. I'd love to get it fixed inexpensively. Such a great helping keeping something from the scrap yard.

Jarod



> There is very little that can go wrong on an induction motor, and with proper maintenance, they can last virtually forever. They don t just go bad or burn up . Problem is, very few people do any kind of maintenance on them and just run them until something fails catastrophically. Bearings (bushings), capacitors and the centrifugal switch are all maintenance items that need to be checked and or replaced every so often. For a three phase motor, just the bearings. Many times, a motor that appears to be failing simply needs to be opened up, given a good cleaning and possible new bearings to bring it back to like new. Capacitors can be checked with a cheap multimeter in resistance mode and are inexpensive to replace. There is no need to go out and spend a hundred bucks or more for a new motor when 99.9% of the time they can be fixed for under $20 and a little effort.
> 
> Cheers,
> Brad
> ...


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## TopamaxSurvivor (May 2, 2008)

> My old Craftsman table saw was doing the same thing a few years ago. Turns out the end bearings (actually bushings) were in bad need of oil. There was a little plastic cap plug at each end of the motor above the bushings. I pulled the caps off and applied a few drops of handy oil to each one and rotated the motor by hand until it worked its way in to the bushings. It s worked fine since then but I do put a few drops of oil in each bushing from time to time.* Don t over-due it with the oil.*
> 
> - ottox1


Good point, just a few drops a year. I have seen motors on equipment that had zerks on the bearings that were greased daily with the rest of the machine. The motor was packed solid, tight with grease!


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## MrUnix (May 18, 2012)

You will rarely see open race greased bearings on anything but industrial machines… but will frequently find those bronze bearing types, particularly on the cheaper motors found on old contractor saws. Funny thing is that if kept properly lubed, they will last way longer than a ball bearing will!

The key to keeping those bronze bushings alive is oil as mentioned… however, they are usually fed via felt packing that rides on the armature shaft through a small opening in the bushing. The felt is saturated with oil and only what is needed is leached out over time. If you run it dry (or even every decade or so anyway), it's best to pull the packing, clean it in solvent, and re-saturate before putting them back in. They tend to be little dirt magnets and will quickly fill up with dirt and grime, similar to an oil filter in a car engine. It's a pretty easy process and will prolong the life of the bearing/shaft significantly. Usually you just have to pop off the press fit cover to access them:










Cheers,
Brad


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## TopamaxSurvivor (May 2, 2008)

The grease filled was definitely industrial ;-)


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