Table Saw Not Starting

Hey All,

I got a hand-me-down table saw and I used to be able to start it by turning it on, and then spinning the blade with a scrap of wood. Now it won’t start up no matter what. A guy from work said I could get a new starting capacitor or something. I looked on the sears website and I can buy parts for the saw.

If I buy the part that is a box where all the wires go to, and has the starter switch on it, will that fix the saw? Or do I need a new motor as well?

Help!

It could be any number of things wrong. First check the outlet you have it plugged into with a lamp. If there’s power there, then the problem is definitely in the saw. However, to narrow down the exact problem, you’ll need at least a continuity meter. Unplug the saw and test each main part of the saw’s circuit: the motor, the switch, and the power cord. Check to see if the saw has either a fuse or a fuseable link. I’ve never seen a power saw motor with a starting capacitor, but there’s always a first time, I suppose.

If you had to “kick start” it, I’d bet the capacitor (the little extra part mounted on the motor) blew out. If it’s this old, the entire motor may be shot by now. If you know who the made it, you could get a replacement motor, otherwise an industrial type store or a machine store will probably be able to help you. If you know anyone who has an account with the http://www.grainger.com will be able to get you an exact or close to match for you. They really do know what they’re doing and are quite helpful (I’ve even had them turn me down a couple of times becuase they couldn’t get a good enough match for me and sent me to a different place). The only problem is, they don’t sell to the general public, you have to have an account with them.

Hey Q.E.D.

The outlet has power. I took the switch housing apart. The ground wire is connected to the table. One power wire goes straight through to the motor. The other power wire goes through the switch. High ohms when switch is ‘off’, zero ohms when switch is on. The power wire leaves the switch and goes to the “Relay”. The relay has two wires coming out going to the motor. One wire output wire has zero ohms to the input wire, the other wire output has high ohms to the input wire.

The two output wires from the relay and the first power wire go to the motor. I can’t probe them at the motor.

It looks like there are three pieces, the switch, the relay, and the motor. The switch appears to be working. I don’t know about the relay or about the motor. The relay is 14.99, and the motor is unavailable.

Would it be a waste to try a new relay? What other tests can I perform?

At the plug, there are High ohms when the switch is ‘off’ and zero ohms when the switch is ‘on.’ It’s an AC motor, so I think that is okay?

Thanks,
-Sandwriter

That’s between the two blades. There are high ohms between either blade and the ground.

Just a woodworker here, but try these before you buy anything. Do you have an air compressor? blow the crap out of the housing … literally… and especially at the ends <. Spray a bunch of electrical contact cleaner in there, let it dry and try turning it on. (if this is an open housing motor?)
2. Pull the cover off the capacitor. If it fried there will be a nasty residue leaking out and it will have to be replaced. Note the MFD # on the side and get one that has the same number .
3. If the capacitor looks OK and blowing out the motor did not work then I go ahead and pull the end off the motor. On larger motors you will find a set of contacts on one end of the shaft that need to be filed clean from time to time. Mark the housing before you crack it apart so that you can line everything up to reassemble. If your motor does not have these contacts,it falls into a category that I have to take to a shop, or just replace.

This is what I go through with something or other around here every couple of weeks and I very rarely have to actually replace a motor.

If it HAS been fried, it is good to assume that it was underpowered for what it was being used for and it is a good idea to replace it with a motor with more HP.

Hope this helps

The motor has 4 areas that can cause the problem. There is the capacitor, the start windings, the centrifugal switch for the start windings or internal wiring for the start components. What “relay” are you referring to? Do you know what the capacitor is? If you try a new capacitor, it must be of the same mfd size.

The brushes in the motor could be shot too. You may have seen a lot of arcing in the vent holes if this was the case.

Hey All,

Thanks for the responses. I need to take the table saw apart to get to the motor. I did use canned air to clear out all the sawdust. I will try some electrical cleaner spray (didn’t think of that) before tear down.

I’ll update tonight.

Unless it’s a “universal motor”, unlikley on a table saw, it has no brushes.

I had the same trouble with my Delta.
I couldn’t figure it out so I took it to a power tool repair shop.
Sawdust had packed into the relay .Duh.
It works just fine now and I learned something.

Yes, I would first check out the relay, which I believe was used in place of a centrifigal switch in older motors. If you could get the saw running by spinning the shaft it sounds like the motors start windings weren’t being energized. And points on the relay close to allow current to flow into the start windings, then open as the motor comes up to speed.

My problem was that the centrifugal starter switch would pack with fine saw dust and no amount of compressed air would clear it out, I would have to remove the end of the motor and pick it clean.

Well, I took the motor apart and I didn’t find any capacitors or centrifugal switches or anything. The three wires, two from the relay and one from the wall go straight to the motor windings. There was some sawdust inside the motor.

I took apart the relay and noticed some slight scorching on the contacts. I will clean the contacts and see if that does anything.

Hopefully CBEscapee is on the money and cleaning the contacts will solve the problem.

I’m done for tonight, I’ll put it back together tomorrow and let you know what happens.

I’m not sure if anyone is following this, but I put it all back together and it still doesn’t work.

So I did find a use for the metal table part. It does a good job of holding up the “4 Free” sign out on the curb.