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

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Forum topic by JarodMorris posted 520 days ago 2139 views 0 times favorited 30 replies Add to Favorites Watch
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JarodMorris

165 posts in 1007 days


520 days ago

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

-- Dad: Someone was supposed to pick up his toys! Son: My name isn't "Someone".


30 replies so far

View JustJoe's profile

JustJoe

1554 posts in 670 days


#1 posted 520 days ago

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)?

-- This Ad Space For Sale! Your Ad Here! Reach a targeted audience! Affordable Rates, easy financing! Contact an ad represenative today at JustJoe's Advertising Consortium.

View TomFran's profile

TomFran

2942 posts in 2625 days


#2 posted 520 days ago

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.

-- Tom, Surfside Beach, SC - Romans 8:28

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JarodMorris

165 posts in 1007 days


#3 posted 520 days ago

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

-- Dad: Someone was supposed to pick up his toys! Son: My name isn't "Someone".

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TomFran

2942 posts in 2625 days


#4 posted 520 days ago

“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.

-- Tom, Surfside Beach, SC - Romans 8:28

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JarodMorris

165 posts in 1007 days


#5 posted 520 days ago

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

-- Dad: Someone was supposed to pick up his toys! Son: My name isn't "Someone".

View wlkjr's profile

wlkjr

10 posts in 533 days


#6 posted 520 days ago

I usually find good deals on capacitors on Ebay.

View Loren's profile (online now)

Loren

7423 posts in 2279 days


#7 posted 520 days ago

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.

-- http://lawoodworking.com

View Shawn Masterson's profile

Shawn Masterson

1253 posts in 580 days


#8 posted 520 days ago

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

View gfadvm's profile

gfadvm

10736 posts in 1321 days


#9 posted 520 days ago

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

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View woodbutcherbynight's profile

woodbutcherbynight

1252 posts in 1040 days


#10 posted 520 days ago

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)

-- Live to tell the stories, they sound better that way.

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JarodMorris

165 posts in 1007 days


#11 posted 520 days ago

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

-- Dad: Someone was supposed to pick up his toys! Son: My name isn't "Someone".

View runswithscissors's profile

runswithscissors

907 posts in 656 days


#12 posted 520 days ago

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.

View gfadvm's profile

gfadvm

10736 posts in 1321 days


#13 posted 520 days ago

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.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View Tomj's profile

Tomj

204 posts in 1013 days


#14 posted 520 days ago

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.

View RonInOhio's profile

RonInOhio

720 posts in 1495 days


#15 posted 520 days ago

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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