Unisaw Issue

[Mark Blatter]

I have a Delta X5 left tilt, 3hp single phase table saw I bought in early 2005. While I have used it a fair bit, by no means has it been over used. I find that occasionally it will shut off after it has been running for 5 - 7 minutes. I presumed it is getting hot, but I took off the side cover and ran it that way and it did the same thing. While I have a heater in my garage, I have it set at about 55 or so for the winter. I truly don't see how it can be overheating, but after it shuts down, it will restart in 3-4 minutes. I don't have a dust collector on it, so airflow is less than ideal. It does it even with light usage, such as cutting expanded PVC, which is about the same as cutting balsa.

Thoughts?

I would like to get it resolved as I have been thinking about replacing it in the next month or two.

Thanks

[Mike Schuch]

Is it an open frame motor... the windings are open to the air? Or is it a TEFC (totally enclosed fan cooled) motor... where the windings are sealed and there is a separate fan to cool the motor?

The previous owner of my Powermatic 65 replaced the (probably a 3ph) motor with a single phase open frame motor. About every 40 hours or so of sawing on it the motor will stop and I have to blow all the saw dust out of the windings... then it is happy again.

Maybe you have dust build up in your windings if it is an open frame motor? Or maybe you have dust build up in the fan section of a TEFC motor?


Many motor starters have heaters in them to prevent overloading the motor. If the heaters are size wrong they will open at a lower current rating than they are supposed to. If you bought the saw new I doubt it would have come with the wrong heaters though.

I assume you are running the saw on 220v? Are you using a long extension cord or anything?

Are the bearings in the motor or the arbor going bad placing an undue load on the motor?

When it stops is the motor hot to the touch?

It should be a life time saw... it would be a shame to get rid of it if it is easily fixable.

[mark kosse]

It sounds like a thermal overload is tripping. The question is why. Is the motor hot to the touch when it stops? If not the overload could be bad or maybe needs cleaned.

[Mark Blatter]

I am pretty sure it is a TEFC motor. I have blown it out a few times so don't believe that is the issue.

I have checked and it is not hot to the touch when it cuts off. I am using about a 50' extension cord on it, but the cord is 3 wire 220 10 gauge wiring, not really an extension cord. At a previous home I was renting, the only way to access 220 was from the outside breaker panel, so I installed an outlet just below the breaker panel and used the 10 gauge wiring as an extension cord, installing plugs on both ends. I would only run the wire in good weather and it would only be plugged in when I used the saw.

Today I am still using the same cord, but it is plugged into an outlet in my garage. I could certainly cut it down in length, but hate to reduce the length unless required.

[Charles Lent]

I think you either have a loose connection in the stop button circuit, or there is a problem with the motor overloads, either the one in the motor or the one adjacent to the contactor. The first thing that I would do is make certain that the blade can be turned freely by hand with the power source unplugged. If it turns free, then check and tighten all of the electrical connections in the start/stop button box and then in the motor control contactor box. If it turns hard, you may have a bearing problem in either the motor or the arbor assembly. If it turns freely and you have all of the electrical connections tight, use the saw for awhile. If you still have the problem, look at, and possibly replace the motor overload heater in the control box next to the contactor. Again, run the saw for awhile. The last possibility is the overload in the motor and the electrical connections in the motor. I've saved these for last because of the difficulty in accessing them. Make certain that all of the electrical connections are tight and possibly consider changing the overload detector - the mechanism just behind the externally accessible red button.

Charley

[Harold Weaver]

First off, ditch the power cord for one of more appropriate length. 50ft. is too long. Secondly, on the bearings, if they spin freely when spun by hand and then continue to spin, then they need to be replaced. There should be a little resistance when turning by hand, if not then the grease is gone.

As others have said, check all the connections in your starter to make sure they are not loose. This machine should be run on nothing less than a 20 amp breaker. You could also have a problem with your capacitor as well. Find a quality motor shop and have them test it, especially since you are not feeling any heat from the motor once it shuts off

[Mike Schuch]

If you were running the saw on a 120v circuit you would need a 20amp circuit. When you double the voltage to 240v you half the current draw. A 15amp 240v circuit should be plenty... hence you haven't tripped the breaker in the breaker panel.

I would try running the saw without the extension cord and see if the problem goe away. 10 gauge at 50 feet should be fine.... but I would test it without the eextension cord and see if the problem goes away.

The overload protection for the motor is either in the starter (switch) or on the motor itself. Since the motor isn't heating up the overload protection sounds like a likely culprit.

[Mark Blatter]

I will give it a shot. I can reduce the length of the extension cord pretty easily, but I don't believe it is the culprit. Just the way it is acting, I think it is in the motor or switch.

I am running it at 220 on a 20 or 30 amp circuit, don't recall now. Will check it when I have a chance.

[Steve Baumgartner]

Check the setting on the overload protector (inside the switch box below the contactor). Nominal is 12A if I recall right. At the right end of the protector is a manual reset button. It is normally popped out and you reset by pressing in then releasing. If you can restart the saw by pressing this (be careful if you do so with the saw plugged in - exposed 220V in there!), the overload is definitely tripping. When that happens it could be either that there really is an overload or that the protector has failed.

[Fidel Fernandez]

I had a similar experience and the culprit was the extension cord.
I bought another 220V machine and that one didn't want to start, so I decided to open the extension cord and check it.
The screws that held the wires inside were loose, after so many years of use. I cut and reset wires and tight the screws and everything is fine now.