PM 66 switch problem

[Ken Gulley]

My 5hp 1ph saw quit working today; worked fine all morning then on the last start up there was a short start, then off, similar to a tripped breaker. I have a mag switch with an overload relay. I'm not familiar with OL relay and wondered if anyone could shed some light on a few things:

- It has a weird reset button next to the stop button (this is internal with the main cover off). this button can be pushed in and turned 90 deg with a screwdriver and it will remain in. I'm not sure how it works...

- There is a dial that can also be turned with a screwdriver; I don't know how that works either. What might this adjust?

Any help or ideas will be appreciated

[Rob Haskell]

My 66 quit working also on Fri. If you hold the green button in it will run fine but as soon as you stop pushing in the contacts let loose. My usual solution is to blow the mag switch box out with the air gun and it starts working again. I tried that but this feels different. Got this saw early 90's, do these switches need replacing? It's gotten alot of use.
Thanks
Rob

[Pete Bradley]

Rob's problem is a very common one with mag starters caused when the contact for the magnet (which holds the circuit closed) gets dust in it. I don't think it applies to Ken though.

Ken, it sounds like you have a starter with an adjustable overload. Since it was working until recently it's not likely that adjustment is the root cause. If the overload is tripping, either the motor is drawing a lot more current all of a sudden (not a good sign), something mechanical is binding, or the overload has failed. I'd start by slipping off the belts and see if the motor and arbor turn freely. Check the wiring for damage or bad/loose connections. If you have a good motor shop near you, they can check the motor out.

Pete

[Ken Gulley]

Thanks, Pete, for your quick response. Yes, mine is different in that holding in the green start button has no effect. I can spin the blade with the belts still on, seems to be as easy as it ever was (with the breaker shut off!) I'm about to get back out to the shop and find my trusty multimeter and check the connections.

Still curious about the little reset button. Does anyone know if it should be out or in. As I mentioned, I can push it in and then turn it and it will stay in. I have done that and it didn't make a difference, but I don't want to have it in the wrong position while I'm trying to diagnose.

Thanks again

[Ken Gulley]

Problem solved...

I was a victim of chasing the "apparent". Since the saw was working all morning then all of a sudden stopped, it was "apparently" the mag switch/overload relay. Then after popping the cover and seeing the buttons mentioned I continued to chase that.

What I should have done, was go back to the basics; check the connections. Sure enough, no 230v to the switch, chased it back to a failed connection at a junction box.

As far as those relay buttons, other than the ones I mentioned originally, there is a small red test square below the current selection dial. You press this to test the overload (it will click and show an orange bar when set), then press the reset to reset it. Similar to the GFI outlets in restrooms.

The reset button has two positions, turning it to the left and having it point towards the H where it remains out, puts in manual mode. Pushing in and turning right towards the A where it remains in puts it in automatic mode. I would think most us home shop guys want it in manual.

BTW, pushing the stop button with the cover on also pushes the reset button inside. So, if you ever do hear your switch "click", just hit the stop button to reset.

Thanks all

[Mike Spanbauer]

Dang Ken, 60 minutes to troubleshoot the whole thing. Heck, it takes me 60 minutes to find my multi-meter sometimes ;)

Glad you figured it out.

mike