# Table saw motor



## jaguar88xj6 (Apr 26, 2010)

I have an old(70"s or 80"s) craftsman table saw(it was given to me and told it ran fine).Heavy cast iron top, direct drive 11.5 amp. The motor won't start on it's own. It hums and sometimes tries to turn left and sometimes right. If I spin the blade it will run slowly and get hot. If I get it spinning enough it will pick up speed and finally kick into high speed. Once there it runs good and cuts fine. It is not a capcitor start. The switch box has a switch and a relay inside. The relay has 3 terminals. 1 on the bottom and 2 on the top. The motor has 3 wires. 1 black,1 white and 1 red. It is wired,black from power cord to the switch, black jumper from switch to single connector on relay, white directly to white from motor, black and red from motor to the 2 other relay termials. The relay shuts the saw down if tipped. The rotor has no exposed windings. It looks like a smooth barrel. I can find any switches inside the motor. Motor seems to have 2 different windings inside. I'm running this saw in a detached garage with 14 guage wire running to the plug. It is not a dedicated circuit. Although my belt drive capacitor start saw runs perfect on the same plug. Any help will be appreciated. Thanks.


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## JohnWill (Oct 19, 2002)

Sounds like a capacitor start motor, are you SURE it's not a capacitor start?

What's the exact model of the saw?


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## jaguar88xj6 (Apr 26, 2010)

That was my first thought also, but there is no capacitor, or any mounting screw holes on the motor and the power cord and motor cord go directly into the switch box and there is no room there for a cap either. I tried using a cap inline with the blackwire and it made no difference, just blew the cap after turning slowly. I'm at a loss. The saw is a Craftsman model 113.226680. Thanks.


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## wacor (Feb 22, 2005)

Bad brushes???

Bad centrifugal switch??


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## JohnWill (Oct 19, 2002)

I can't believe this is a 100% induction motor, not to drive a saw! There has to be either a cap or at least the centrifugal switch mentioned by wacor.


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## jaguar88xj6 (Apr 26, 2010)

When I was given this saw it had a replacement motor(same as the original) and the original that burned up. They both have all the wiring and switch all originally conected. Hard wired to motor, pluged into relay in switch box. Power cord plugged into switch in switch box. You may be right, but I took the old motor and switch box apart and can find no cap. I don't know what a centrificul switch should look like, but don't see anything in the motor that looks like it could be one. What should I be looking for? Thanks.


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## jaguar88xj6 (Apr 26, 2010)

Sorry. I forgot to mention that this motor also has no brushes. Thanks again.


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## Mumbodog (Oct 3, 2007)

If there is no capacitor, then it has a centrifugal switch on the shaft inside the motor, it is stuck in the run position, most of the time you can clean and lightly lubricate it to return it to working order.

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## JohnWill (Oct 19, 2002)

Yep, the centrifugal clearly has to rotate, so it's on the armature somewhere.


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## Mumbodog (Oct 3, 2007)

Its fixed to the armature (usually at the back end of the motor), it rotates with the armature, it has springs that keep it on the start windings of the field, when the armature reaches a certain RPM the centrifugal forces overcome the springs and switch current to the run windings of the field. This mechanism can get dirty and stick in the open position, and the motor cannot start on the run windings. Clean it and it should close and work normally. In extreme cases the centrifugal switch will need replaced, any motor rewinding shop will have them, and if they are nice, will sell you one at a reasonable price, otherwise replace the motor, Harbor Freight has reasonably priced replacement motors for table saws.

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## jaguar88xj6 (Apr 26, 2010)

Thank you all. Will look for the switch and see if I can free it up.


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## Koot (Nov 25, 2007)

*Here ya go*


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## K7M (Feb 27, 2000)

According to this parts list it is a start relay. Part #32.
http://www.searspartsdirect.com/par...scription=FIGURE 1&documentId=00044242&blt=06
I don't see any centrifugal switch or cap anywhere in the parts list.


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## wacor (Feb 22, 2005)

If there is a relay would there not be a capacitor though??

The motors I work on that are capacitor start have a relay to take the start winding out of play. 

I am not familiar with the centrifugal switch other than remembering some of the older motors having them. If there was a cent. switch would there not be a need for a relay?


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## paisanol69 (Sep 7, 2005)

Koot said:


> *Here ya go*


...Not poking fun at you Koot, But at the Sears link you posted, it's obvious that whoever Sears hired for their data entry update work , for their online parts dept, definately did NOT HAVE A CLUE !!

I guess since the main item is a table saw, whoever did the data entry figures that these "minature blades"were for the hobbist that deals in smaller jobs!!!

And when you click on K7M's link, there a socket from what looks like a 3/8" drive set, listed as a "nut" ! Jeesh, I would hate to have to depend on Sears online repair catalogue, fo parts!!


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## jaguar88xj6 (Apr 26, 2010)

The relay in the switch box is not what you would think of as a normal relay. It has a piston inside that connects the hot wire from the switch to the motor black and red leads. It must be in an upright position to make contact. If it's tipped(ie saw falling over) the piston drops and contact is lost shutting off the power. Same idea as a mercury switch.


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## Koot (Nov 25, 2007)

paisanol69 said:


> ...Not poking fun at you Koot, But at the Sears link you posted, it's obvious that whoever Sears hired for their data entry update work , for their online parts dept, definately did NOT HAVE A CLUE !!
> 
> I guess since the main item is a table saw, whoever did the data entry figures that these "minature blades"were for the hobbist that deals in smaller jobs!!!
> 
> And when you click on K7M's link, there a socket from what looks like a 3/8" drive set, listed as a "nut" ! Jeesh, I would hate to have to depend on Sears online repair catalogue, fo parts!!


I saw that too! Thanks for not poking fun at me for Sears' incompetence. All I did was offer the link for the table saw parts breakdown (as Sears thought they should be listed).


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## djo1810do (Apr 15, 2010)

Yes I have a 10in. Craftsman older cast iron top. As yours. I,m thinking the brushes in the moter are flat and need replacing. please let me tell you, I dont do that replacement alone. So this meerly is a sugestion. Good day.


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## JohnWill (Oct 19, 2002)

FWIW, I've had pretty good luck with Sears Parts for my tools. I'm keeping my 40 year old radial arm saw running using them, good as new.


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## jaguar88xj6 (Apr 26, 2010)

If your motor is like mine, it does not have brushes.


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## jaguar88xj6 (Apr 26, 2010)

Just an update. I found out that the start windings are burnt. I rewired the moter using a capacitor and a 2 way switch. In 1 position the power goes through a capictor and the motor starts running at a slow speed. After starting the switch is flipped to the 2 position. This takes the cap out of the circuit and the line power goes directly to the run windings and the motor jumps up to full speed and runs good. The only problem is the common(white ) wire gets hot after a few minuets. The white is the only wire not going through the switch. It is connected directly from the power cord to the motor.Why is this? The power wires(black and red do not get hot). I'm determined to get this right. Thanks


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## JohnWill (Oct 19, 2002)

Buy a new motor!


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## jaguar88xj6 (Apr 26, 2010)

Easier said than done. It's a direct drive(threaded shaft) that is no longer in production.


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## JohnWill (Oct 19, 2002)

Buy a new saw.


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## jaguar88xj6 (Apr 26, 2010)

Already did that. Got a belt drive. Just want to tinker with this one, if it's alright with you?


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## JohnWill (Oct 19, 2002)

jaguar88xj6 said:


> Already did that. Got a belt drive. Just want to tinker with this one, if it's alright with you?


It's fine with me.


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## Koot (Nov 25, 2007)

jaguar88xj6 said:


> Just an update. I found out that the start windings are burnt. I rewired the moter using a capacitor and a 2 way switch. In 1 position the power goes through a capictor and the motor starts running at a slow speed. After starting the switch is flipped to the 2 position. This takes the cap out of the circuit and the line power goes directly to the run windings and the motor jumps up to full speed and runs good. The only problem is the common(white ) wire gets hot after a few minuets. The white is the only wire not going through the switch. It is connected directly from the power cord to the motor.Why is this? The power wires(black and red do not get hot). I'm determined to get this right. Thanks


Draw out your motor and switch setup on paper and make sure the cap really is taken-out of not only the motor winding circuit, but also that the cap does remain part of the electrical feed. If the capacitor (which you are using to aid the start winding) is allowed to remain part of the electric circuit (any part of the "electrical") it could produce an unwanted impedance (resistive ~ reactance) on your neutral return wire...especially if one of the motor windings backfeeds energy through the capacitor and into the hot or neutral. Capacitors can introduce some heavy and unusual electrical burdens if not switched-out entirely because they alter [delay] the normal [electrical] phase angle...


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