(09-05-2018, 05:49 AM)TDKPE Wrote: So that suggests the motor is good, as is the wiring to it, and the contacts inside the contactor. 

What's not working is the control circuit, which pulls the contactor closed and holds it there until the Stop button is pushed or the overload device opens.  I would start with potentially loose or broken wiring, as that's the easiest thing to find and fix.  There's probably an auxiliary set of contacts mechanically linked to (more like piggy-back onto) the main contactor, which may have failed. 

If the Stop button is stuck in or a wire to/from it  is loose or the switch is otherwise is not closing that part of the control circuit, it will do what it's doing now - it won't start with the Start button, but will run if you manually close the contactor but only while you're holding it.  Start with blowing it out with compressed air.

Unplugged for safety, can you see the small set of contacts on the side of the main contactor, probably with small wires to it, closing when you close the main contactor manually?

And I agree with fishhh4 and Wild Turkey - it's a Furnas, and highly repairable, and you could take it to a motor repair shop or good electrical supply house and let them have a look if you're not comfortable troubleshooting it and replacing parts if necessary.  But they're industrial strength units, and worth fixing, IMO at least.

(09-05-2018, 08:56 AM)woodcutter100 Wrote: Update.. took the contactor out of the box plugged the saw in hit the switch and it worked. Put every thing back together and it works. I have no idea what I did to make it go but I aint complainin. Thanks for the great suggestions and I will keep them in mind if it happens again.

(09-04-2018, 06:08 PM)TDKPE Wrote: Can you show a pic of the internals?  An old Furnas will likely have a NEMA contactor with auxiliary contacts for the push button station plus heaters for overload protection, and a transformer if it's a low-voltage control.  Any of those parts should be replaceable.  

Alternatively, you can just buy a complete motor control unit from Grizzly and others for about $100.  Like this one, for 3 hp motors on 240V circuits.  http://www.grizzly.com/products/Magnetic-Switch-Single-Phase-220V-Only-3HP-21-25A/T24101

There are others for the same price for different voltages and max hp ratings and current ranges.