Unisaw issue

[J D Thomas]

From out of left field today. I pushed the start button on my Unisaw, and it started then immediately shut off. I repeated this several times and ultimately the start button did nothing. Power to the saw was fine; breaker fine; no blade obstruction; everything seemed fine on the surface. I unplugged and replugged the power cord. Same thing again. After a few repeats of this scenario, the saw started and ran fine. Hmm.

Feels like something is beginning to go awry. Can anyone point me in the right direction? Capacitor? Maybe something else?

The Unisaw is a Classic White model, purchased new in 1998. No issues until today.

Thanks all.

[Carroll Courtney]

If you have a starter,then the overloads may be trip.With power off, try to reset them.On the starter cover there may be a external button,if not then you will have to remove the cover and hit the reset button.Or if you don't have a starter then the motor may have internal OL's which there should be a reset button on the motor.Again w/ power off,good luck and keep us posted----Carroll

[Harvey Melvin Richards]

Pull apart your start switch. It may be packed with sawdust. Also check the condition of the contacts. Sometimes they get burned and need to be lightly filed or abraded clean.

[Bob Wingard]

The holding relay is not latching, and the push-button is acting as a momentary contact switch. Take the cover off and get a picture of the insides ... it will help diagnose the problem.

[Bill Bukovec]

Have you looked for bad connections within the switch box? (I'm guessing by now you have)

I remember a similar thread and the problem was a bad crimp terminal on a wire.

Do you have a schematic that shows the wiring for the start and run windings? If so, track down your run winding connections and check for bad connections.

It may be helpful to talk to a tech at Delta. I have always had good luck when I called them.

Bill

[Larry Fox]

Happens to my X5 Uni every once in a while. When it does I remove the cover from the starter switch, give it a good once over with the air hose, check that the reset has not tripped and reassemble. Works every time - total elapsed time < 3 minutes.

[J D Thomas]

If you have a starter,then the overloads may be trip.With power off, try to reset them.On the starter cover there may be a external button,if not then you will have to remove the cover and hit the reset button.Or if you don't have a starter then the motor may have internal OL's which there should be a reset button on the motor.Again w/ power off,good luck and keep us posted----Carroll

Try as I might, I could not locate any reset switch. Nothing external on the motor and I took the square cover off one spot and that's where the wiring was located. I did blow that out. I also took the cover off the starter; clean as a whistle.

I'm curious as to the reset button or switch, since the saw did eventually start running normally. Hmm.

[Kevin W Johnson]

As long as it started running, it's not a reset problem.

As previously suggested, if you have a magnetic starter, it sounds like it isn't holding. Otherwise, with the power unplugged, check and tighten all associated electrical connections. If your saw is single phase, carefully check the wires that connect to the capacitors and make sure they are tight. Make sure you don't short the terminals together if your unfamiliar.

Might post a few pictures of what you have, with any boxes opened up. That would the people here narrow in on what your dealing with.

[Dan Hahr]

Sometimes my red stop button sticks in slightly, just enough to turn the saw off after the start button is released. I bump it a little and it loosens up. Other times, I leave my sled lying against the stop button accidentally. Very annoying.
Dan

[J D Thomas]

As long as it started running, it's not a reset problem.

This make sense to me.

Might post a few pictures of what you have, with any boxes opened up. That would the people here narrow in on what your dealing with.

Good idea Kevin. I took a few CUs of the switch attached here. I did blow it out even tho it appeared to be very clean when I pulled the cover.

Any suggestions are appreciated. You've all provided good insight on this for me.

Thanks.

UnisawSw1.jpgUnisawSw2.jpgUnisawSw3.jpg

[Jim Neeley]

JD,

The white circle near the lower left corner with the numbers 10 - 14 and the letter "A" on it is the overload setting for the switch. If the problem continues I would turn that *slightly* from 12 to perhaps 12.5 (amps) and see if your problem goes away. If it was set a little too close to what the motor draws when new, any small current increase due to aging (a little friction on the bearings or ???) may cause it to cross over the trip point. I do not recommend "cranking it up" as the overloads are there for a reason but a *little* shouldn't hurt anything.

If the problem goes away, I'd just use it that way. If it didn't, I would not crank it up more but would get the saw checked out by a motor specialist. I'd look in the yellow pages for a company that rebuilds electric motors and ask them for a referral. IMO this isn't thee best job for the rank-and-file electrician. Nothing against electricians and some could do it but I believe many more without enough experience in motors will claim to know all about it.

Just my $0.02.. YMMV.

Jim

[J D Thomas]

The saw was working fine during the week and I kind of hoped the issue resolved itself. Yeah right.

This morning it started doing the same thing and at one point quickly degraded to zip-a-dee-doo-dah; nothing.

I went back in to take a closer look at the switch innards and discovered the L1 and L3 terminals where the line connections are made were really LOOSE. Moreover, they couldn't be tightened; felt like the screw threads were stripped. From the looks of things this has probably been an ongoing issue. It looked and smelled like it today.

Bottom line, the switch is toast and it's time to order a new one. Hey, what else do I have to throw a couple hundred bucks toward… Well, let me think… naw, don't want to go there!!

Thanks again to all who chimed in with their expertise.

[Kevin W Johnson]

Glad you figured out where the problem lies.

Make a diagram of all the connections, and label wires if need be. Remove the old starter and/or see if you can remove the screws that won't tighten up. It might be that they were over torqued at the factory, and you may be able to install new screws. I'm guessing/hoping that the screws are softer then what they screw into, so maybe it's just the screws that are stripped. If so, it'd be way cheaper than a new starter.

[J D Thomas]

Actually, way ahead of you Kevin. That was my first reaction. But upon trying to disassemble things to the point of repair, it quickly became obvious to me that the best approach would be to replace it. The deeper I went the more I realized the damage was done. Time to bite and just do it right.

[Kevin W Johnson]

Good to know you gave it your best shot. Win some, lose some.