Table Saw Motor

[From Mystic]

Well, I picked-up a older Craftsman table saw last year and the motor gave out yesterday. Turned it on and it turned real slow then stopped. Its an older 1hp motor.

So the table is nice and heavy and its got a nice base on it so I'm thinking of replacing the motor.

Any thoughts on where I should look?

I'm thinking of getting alittle bigger motor also.

Any thoughts would be great. FM

[TimH]

Old Powermatic 66 - $1100

Reply to: sale-623363111@craigslist.org (sale-623363111@craigslist.org?subject=Old%20Powermatic% 2066%20-%20$1100)
Date: 2008-03-29, 3:24PM PDT


This is an old 66, one of the very early ones. S/N 66-1677, which makes it no newer than 1968.

About 5 years ago I refurbished it. Ground the top flat, replaced the arbor bearings, repainted (matching the original pea-green color). I put on a new Powermatic Biesemeyer-style fence, replaced the UHMW on it with HPL on appleply, and put Starrett rules on the fence bar.

The machine was originally in a middle-school or high-school shop. It is a 2 horse, 3 phase machine. It is completely functional & runs smooth.

Included with the saw:

-24” rails shown
-52” rails (not shown)
-Shop-made table for 52” rails, with adjustable legs
-Fence
-shop-made teak knee-stop
-some shop made zero-clearance inserts
http://images.craigslist.org/010202011603010401200803291bc9f59aa9d77f176f00da5d .jpghttp://images.craigslist.org/0115060104000116052008032946112d5ceaeafccedf000eec .jpghttp://images.craigslist.org/010104011503011611200803291c0602c2ccbce09047003770 .jpg

[sv Lorelei]

Check Graingers. I'd try and match the frame size and RPM's, and don't get a low slip motor (Class A or B). Ideally you want a Class F or higher.

[Rob Stokes, N. Vancouver]

I'd call your local tools stores - the ones that sell off-shore stationary equipment and see if they have a 1.5HP motor. If they do, it should be a bolt-in. You can also try www.grizzly.com as they sell spares, and of course you can also try your local motor ships for a Baldor etc.

Rob

[Lulworth]

These old motors are hard to kill. On my old 1950's craftsman, when the the motor stopped working, I fixed it by disassembling the motor casing and cleaning the accumulated dust out of it. It may be enough to simply blow the dust out of it -- I may be making this up but I think there is a centrifugal switch that can get bunged-up with dust but is necessary to disconnect the starting capacitor after the motor starts turning. Be careful but here is a test: take the belt off the motor pulley then wrap a thin rope several times around the pulley (don't tie it but wrap it so that the end comes off at the end of the pull). Turn the motor on and give the rope a pull so that the motor is turning (in the right direction). If you pull it fast and it starts running like normal you know the problem is related to the capacitor start (but is probably the switch). This is almost always the problem (or so I'm told).

David

[kc8pql]

These old motors are hard to kill. On my old 1950's craftsman, when the the motor stopped working, I fixed it by disassembling the motor casing and cleaning the accumulated dust out of it. It may be enough to simply blow the dust out of it --

Exactly. I have an old saw with an open frame motor that I've brought back from the dead several times by blowing the dust out of it.

[Bob Cleek]

Exactly what Lulworth said. If it is a Craftsman motor of the same vintage as the saw, it should be essentially bulletproof. It's also probably the right size for the saw. I'm not a big fan of overpowering older table saws. The saw is engineered for a particular horsepower. Don't overpower it.

The capacitor "kick starts" the motor turning with a hit of juice to overcome the inertia. Once it gets rolling, the motor will run fine on its own. Using a cord to get the motor turning, like starting a lawnmower, will give you the same effect. If that does it, then you need to replace the capacitor. Sears doesn't have the replacement capacitor anymore, last I needed one. You can get them from any decent electronics store. The tricky part is finding one that will fit into the base of the motor. I didn't find that too hard, though.

No question, too, clean the bugger out now and then with a blast of compressed air. That will reduce the resistance to turning that may be stalling the motor out. Most cases, though, it's the capacitor that has crapped out. No reason to throw out a motor like that if it can be easily fixed. They don't make 'em like that anymore, ya know.

[Cuyahoga Chuck]

Well, I picked-up a older Craftsman table saw last year and the motor gave out yesterday. Turned it on and it turned real slow then stopped. Its an older 1hp motor.

So the table is nice and heavy and its got a nice base on it so I'm thinking of replacing the motor.

Any thoughts on where I should look?

I'm thinking of getting alittle bigger motor also.

Any thoughts would be great. FM

I wouldn't give up on it without checking it out. If it is not a sealed motor it may have ingested a lethal amount of sawdust or run out of brush contact.

[From Mystic]

Well I thought I had it.

I rook the motor apart tonight. There was alot of dust in there. I cleaned it all out. I plugged it in and it started spinning. Yippie!

However when I set it all back it still seemed to be running slow and after about 30 seconds just cut out again.

Not sure what to do. The fact that it did run makes me want to try and use this motor,

Any ideas what would make it just cut out like that.

I did try the capacitor test. Nothing. FM

[Ron Williamson]

It could also be that the centrifugal contacts(points) that engage the capacitor aren't working.
They are supposed to engage the capacitor for starting,then pop open at a certain RPM.
I've yet to find a bad cap.,but have found plenty of burned and dirty points.
R

[Tylerdurden]

Make sure the centrifugal switch drops out. Sounds like she is stuck in start. If you give me the frame of the motor I will look and see if I have one in the shop. Mark

[From Mystic]

Hello all

Thanks for all the replys. It turned out to be the thermal switch on the motor. Little red button on the motor itself. Replaced it and motor works fine.

This site is a great place to get information. I not only was able to fix my saw but learned abit more about electric motors.

Thanks from mystic

[andrewe]

Just a point, the motors with centrifugal switches don't have capacitors. They have a set of 'start' windings that the switch disconnects when the revs. rise. More torque than a capaciter, but more expensive too, so not common on new kit. (3ph. motors have neither.)
A

[TerryLL]

Just a point, the motors with centrifugal switches don't have capacitors. They have a set of 'start' windings that the switch disconnects when the revs. rise. More torque than a capaciter, but more expensive too, so not common on new kit. (3ph. motors have neither.)
A

A correction if I might.
Capacitor-start induction motors use a capacitor to shift the phase in the start winding. Once the motor attains a certain speed, a centrifugal switch removes both the capacitor and the start winding from the circuit. This configuration of capacitor and centrifugal switch is found in induction motors from fractional HP up to several HP. The capacitor does not produce the starting torque, but only serves to shift the phase of the starting current through the start winding. It is the magnetic field of the start winding that produces the starting torque. 3HP motors of this type are common.

[andrewe]

My comments were based on personal experience only, so correction in order. I have taken quite a few motors apart and have yet to find one that has both capacitor and centrifugal switch. This is up to about 8 hp, I had some bigger 3 ph. pump motors that have external time delayed contactors that switch from starter windings to run. 15 to 25 hp.
In my shop I have a couple of switched small motors (metal lathe and pillar drill) all the rest are cap. start , all 230v.single phase. (std. european voltage)
Andrew

[David W Pratt]

Mine was old when I bought it 25 years ago. Did have to replace the capacitor.
Walked into the store and held it out, the guy didn't even turn around, he just reached out and got one off the shelf, $12.00 IIRC.