Unisaw won't start - electical??

[Carl Moser]

My Unisaw series 34-450 1971 vintage won't start up.
Pressing the START button does nothing - no click, nothing, total silence.

I checked that I have 220vac at the saw and 220vac on the switch contacts.
Could it be a starter capacitor? Are these inside the motor?

Carl

[Kieran Kammerer]

Was it working before? Does it have an old switch or a newer type switch on it? Some times with mine I have to unplug the saw to reset things and then it starts right back up. Worth a try.

[Steve Griffin]

After checking the breaker, the next step I'd do is start spraying out everything. Takeoff the switch cover and spray it out and maybe clean the contacts with sandpaper. Take off the capacitor cover and spray that area out and of course spray out the motor.
Most of the time, that is the trouble with motors. The rest of the time, the trouble is usually the motor itself.

[Carl Moser]

I purchased my Unisaw last week. It was at an auction of a company where it sat unused for a few years.
I got it home and it worked great until it suddenly stopped working.

Here is the front switch and back control box. Not familar with what the control box -- circuit breaker or interlock???
The red button in the control box presses in and the cover has a copper metal piece that presses on the red button.

Carl

[Rod Sheridan]

Measure the voltage at the switch on the line side, and the voltage on the load side (motor side).

If you have 240 volts on both, then it's a problem with the motor wiring/motor.

Make sure you measure across the switch, not to ground..............Rod.

[Richard Coers]

If it's a start capacitor, the motor will hum, but not spin. Any noise at the motor?

[Carl Moser]

If it's a start capacitor, the motor will hum, but not spin. Any noise at the motor?

I found the problem -- there was a short in the Control Box -- note Red Arrow.
As part of my restoration I'm going to dress these wire connections a little better.

There is a box hanging off the motor. I opened it searching for the Starting Capacitor
but all was in there was a lot of sawdust and wire nuts. Amazing how sawdust can
collect everywhere.

That Red Switch in my control box must not be an Interlock because the Saw will
run with the cover off. Is it a Circuit Breaker or Thermal Overload Switch?

Also, for my information just in case I have a problem in the future, where in the Motor
is the Starting Capacitor.

[Richard Coers]

I found the problem -- there was a short in the Control Box -- note Red Arrow.
As part of my restoration I'm going to dress these wire connections a little better.

There is a box hanging off the motor. I opened it searching for the Starting Capacitor
but all was in there was a lot of sawdust and wire nuts. Amazing how sawdust can
collect everywhere.

That Red Switch in my control box must not be an Interlock because the Saw will
run with the cover off. Is it a Circuit Breaker or Thermal Overload Switch?

Also, for my information just in case I have a problem in the future, where in the Motor
is the Starting Capacitor.

There is a half round lump on the outside of the motor, about 5" long. Inside the metal can, the capacitor is hard plastic. Capacitors can hold energy, even with the electricity disconnected. Short it out with an insulated screwdriver, across both terminals, before unhooking the wires.