I have a question about my table saw. It is a 10" Rockwell table saw that is about 30+ years old. Lately when I run it the motor has been coming up to speed but then slowing down and speeding up on its own (without a load). I checked the brushes and they look OK. Any idea what could be causing this or how to fix it?
Woody
What kind of motor would that be? Your saw is rather young to have been supplied with a repulsion-induction motoe. If it has a universal motor, it is rather old to have the original one.
In the case of the repulsion-induction motor, a failing centrifugal switch would cause this problem. There may be other reasons as well.
If you have a universal motor, I don't know. The no load speed of these things is usually limited by friction in the bearings. Perhaps the bearings need replacement. There may be other reasons as well.
I would take it to an electric motor repair place. Those guys see more bad motors in a week than we do in our entire life.
Jim
It has the original motor. I don't know what type it is, just that it is not a separate motor, but instead is integrated into the arbor that turns the blade (via a very short 6" belt). Today I disassembled the saw, removed the blade and turned it over (table down) and ran the motor for awhile. At first it varied speed as before, but after a few minutes it started running at constant speed. I guess tomorrow I'll turn it back over and see if it still runs constant or varies again.
Woody
It is a universal motor which uses the direct drive method. This is the same mechanism used in circular saws.
You could take it apart and lubricate the bearings.
Jim
I greased up the transmission and noticed that a lot of the grease was coming out of the joints, so I checked all of the bolts and found many of them loose from years of vibration. I guess that was also preventing the grease from being fully distributed inside, and once I tightened the bolts and re-greased, the problem was fixed.
Thanks for your suggestions, Jim.
Woody
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