New with a question

[Robert 2006]

Hi,
New to the post in San Diego, Ca. I have had this happen two time now and would like to see if any one else has seen or had this problem. I have a Delta cabinet table saw that justs starts automatically:( . Used the saw the day before the next day go into the shop to find the table saw running not a good feeling, not sure how long the saw ran for but the motor is hot to the touch. Would a spike in the power or the contacts on the sealed switch? I will be contacting Delta on Monday to see if there was any recalls on the problem. Thanks in addvance for the help.

Robert

[Don]

Hey, Robert and welcome to the forum. I've worked with these saws and ones similar all my life - this is the first that I've heard of a situation like this. I don't know what model you have but I'm going to assume that you have one of the full size "cabinet" shop saws. These units usually start with about a 3hp motor and most often are 220. This type of saw has a two part starting and stopping system and it's easy to tell you if you have the one that I'm going to describe. If you start your saw and then unplug it, then plug it back in; it will NOT resume running, correct?

This means that you have a low voltage starting system. The buttons that you push to start the saw complete the circuit on usually a 12 or 24 volt subsystem, this in turn causes the larger contacts to close on a magnetic contactor. This contactor has larger contacts that actually complete the circuit to the the motor. This type of system solves a couple of problems; in power outage situation the saw will not start on it's own. The magnetic contactor connects the circuit in a micro-second, this keeps the contacts from burning out due to the load of the motor. The contactor usually has some load heaters in it to cancel the run in an overload/overheat situation.

Here's my guess on your situation. The micro-switches that start your saw are binding and obviously the start button. I bet that on your saw you only have to breath on the switch to get it to run, true? If that's so the contact is so slight that something might be changing in your shop, temperature, etc. that causes the circuit to close. You might want to take the cover off of the start switch and examine it for debris or incorrect assembly. This is the only thing that could be causing the start system to energize the saw.

Now . . if you have a smaller saw with just a simple switch - the switch is bad/broken and needs to be replaced. You have an unusual situation and you do need to get to the bottom of it, it could start on you while you are changing a blade or using the surface for storage. I'd always unplug this puppy until you get things right.

Let us know what you find out, or if you need to give us more information.

All the best, Don

[jerrymayfield]

It can be hazardous giving electrical advice. What you are attempting to explain is no voltage protection(3 wire control) where (if running) if power is lost and then restored the motor must go through the normal starting procedure before it will restart. It is certainly possible to have line voltage applied to the coil of the starter(if it has overload protection it is a starter) thats not good if you are expecting 12 or 24volts. One more thing the nominal voltage in the USA has been 240 for over fourty years.

Regards

Jerry

[Don]

Thanks for the reply, Jerry, and the heads up on the possible dangers of electricity. Do you have any helpful and practical solutions to this member's problem?

[jerrymayfield]

It is most likely some mal-function in the starting or holding circuit. First remove all power then look at the start button wires and contacts then the holding circuit wires and contacts. These are the most likely places for this type of problem.

Regards

Jerry

[Joe C]

Robert,
I would definitely have that looked at. In the mean time, I would disconnect the power to the saw when not in use.