table saw motor binding electrical smoke resistance noise jerky....how BAD

[bentley]

My table saw motor has gone bad. It was like the blade was binding on something, and came to a fast stop when switched off. Then there was significant electrical smoke I had to air out. I unplugged it for a day. Now when I plug it in and start it it seems as if there is a series of jerky electrical resistance spurts, accompanied by a pulsating noise. Like the motor is firing against itself - resisting its own powered rotation by sending quick spurts of electricity power in the wrong direction. Rough, brief, jerky rotation.

It came with a complete manual listing all parts including a full motor, but also has a separate exploded parts illustration of just the motor. Unfortunately it's out of warranty. So can I suspect to replace any parts, without having to replace the whole motor?

table saw motor binding electrical smoke resistance noise jerky....how BAD

Mastercraft 55-6886-6 10" 15A 120V 60Hz 3.0 hp max 5000 rpm no-load speed

[notbob]

Sounds like might be worn/bad brushes or commutator. How deep are you willing to go to save a buck? May be best to jes replace motor.

nb

[Lew Hodgett]

Congratulations, you get to help jump start the economy by purchasing a replacement motor.

By the time you price out a replacement universal motor, you may find a new saw price to be just as attractive.

Lew

[Bob F]

If it is belt drive, have you taken off the belt to verify the motor is the problem?

[John Grabowski]

*You may be able to save some bucks and have it rebuilt at an electric motor repair shop. Check the yellow pages. If nothing else they can tell you what is wrong with it. You might want to add thermal protection onto the motor control of your saw to prevent future damage to the motor.

[Tony R.]

The hard part is, putting the smoke back in.

[Doug Winterburn]

Well, it could be a direct drive universal motor...

[Tony Hwang]

Hi, Does the motor have capacitor? It may be shot.

[Ed Pawlowski]

Ah yes, some small saws with universal motors have brushes. Glad you were able to learn something from Usenet today.

[notbob]

I will admit ignorance of "table saw motor". Are you saying there are no brushes in universal single phase AC motors? I'm sure Milwaukee would love to know this.

nb

[bentley]

There is a brush assembly part number. What does this mean? (if anything different)

There is no belt. The blade is bolted to the shaft.

There seems to be no capacitor, but a circuit breaker / rocker switch. I cleaned this circuit breaker / rocker switch out once as it has stopped working, but I can't see this being the problem this time. Could it?

[Tony Hwang]

Hi, Mastercraft is maybe even lesser than Sears tools.

[Lew Hodgett]

5,000 RPM should have given you the clue this is a universal motor and thus has brushes.

So much for your electrical knowledge.

Lew

[PDQ]

Just shows to go you ---A little knowledge can be a dangerous thing. And, some times, it is the littlest minds that tend to dump on others = the most.

P D Q

[PeterD]

Yes, many of the 'newer' cheap ones use brushes. Not surprising at all.

[JIMMIE]

They may be full of sawdust?

Jimmie

[David Nebenzahl]

On 4/4/2009 1:29 PM notbob spake thus:

Brushes for a *table saw motor*?

Just goes to prove the value of advice you get from Usenet ...

[David Nebenzahl]

On 4/4/2009 3:02 PM Doug Winterburn spake thus:

You mean like on one of them cheap "motorized" saws? I thought the O.P. had a *real* table saw. So yeah, I guess it could have brushes, but not likely.

[Lew Hodgett]

Yes.

Saw is a "Kung FU Machinerty" Special.

I bought one for $50 in the mid '80s to throw in back of car for use at the boat yard.

If you get 2 years, consider yourself lucky.

Lew

[David Nebenzahl]

On 4/4/2009 3:27 PM Lew Hodgett spake thus:

Whoops; missed that part of the post. So it does have brushes.