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

"woodman" wrote in message
news:PQqQi.972$tX1.498@trndny05...
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


"Jim" wrote in message
t...

"woodman" wrote in message
news:PQqQi.972$tX1.498@trndny05...
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

"woodman" wrote in message
news:fmyQi.999$tX1.614@trndny05...
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


"Jim" wrote in message
t...

"woodman" wrote in message
news:PQqQi.972$tX1.498@trndny05...
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 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


"Jim" wrote in message
...

"woodman" wrote in message
news:fmyQi.999$tX1.614@trndny05...
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


"Jim" wrote in message
t...

"woodman" wrote in message
news:PQqQi.972$tX1.498@trndny05...
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 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