Testing table saw paddle switch

[Kaizen]

My old table saw has recently refused to start. It sounds like there is something jammed in it so I just get that buzzing sound. Hoped it was the switch but got confused on how to test it once opened. I have 117 bolts on the feed. But under the feed screws were also one wire going out. I assume those go to a starter as it’s constant voltage? On the other side of the switch is another wire. Do I still test between just the two sides for continuity? Any way to jump out the switch to start diagnosing motor/starter? This I believe is 1.5 or 2 hp 120 volt






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[Jim greengo]

I'd check straight across from black wire for continuity with switch off,then check it again with switch on to see if it changes.

 

[wyliesdiesels]

There should be a coil with 2 terminals.

Connect the terminals and you should be getting 120v on the output side of the contactor.

 

[dogdog]

Looks like a DPST to me... means that switch switches both neutral and hot when on and off not just HOT in most case... most power tools are like that as well...

so when on two set of the screws would have continuity.... Just test with a continuity meter also an ohm meter... for me.. mine (craftsman saw..) had arc pitted so bad on the hard contact point.. that prevented electricity flow... I have a thread few years ago and pics .. not sure... I just open the switch, took the two contact points out and wire wheel it, sand paper it, then put it back and greased it... been fine so far.. at least 2 or 3 years now...

Anyways... if you are adventurous , then go check...

the motor looks like it's hard wired... it is just two lead 120V AC... you can't change direction or voltage that is why you only see two wires out... excluding the ground...



add:

this is my post about that HY56 look alike switch... same thing with the Jet Drill press I have from the 90s arcing inside caused the switch points to be not conductive

only uploaded the pic of the contact point that have been cleaned up... It was black or sooted when I took it out.. YMMV.


https://www.garagejournal.com/forum/showthread.php?t=332512

 

[dogdog]

HY56 looks like a standard generic DPST.. double pole single throw...

Line side has hot and neutral and load side the switched hot and neutral... two switch in one... same as my craftsman one. pretty sure it's generic and typical for most power tools...


https://www.lumberjocks.com/replies/on/10541985

 

[James-W]

What is causing the buzzing sound, the motor or the switch? If the buzzing sound is coming from the motor then it is likely you have shorted starter windings or you have a defective starter winding switch. If the starter windings won't start the motor turning, then you will get a hum or a buzz from the motor. You can try turning the motor by hand when it is buzzing and see if it starts. If it does, you know the problem is with the starter windings.

 

[Kaizen]

Looks like a DPST to me... means that switch switches both neutral and hot when on and off not just HOT in most case... most power tools are like that as well...

so when on two set of the screws would have continuity.... Just test with a continuity meter also an ohm meter... for me.. mine (craftsman saw..) had arc pitted so bad on the hard contact point.. that prevented electricity flow... I have a thread few years ago and pics .. not sure... I just open the switch, took the two contact points out and wire wheel it, sand paper it, then put it back and greased it... been fine so far.. at least 2 or 3 years now...

Anyways... if you are advantageous, then go check...

the motor looks like it's hard wired... it is just two lead 120V AC... you can't change direction or voltage that is why you only see two wires out... excluding the ground...



add:

this is my post about that HY56 look alike switch... same thing with the Jet Drill press I have from the 90s arcing inside caused the switch points to be not conductive

only uploaded the pic of the contact point that have been cleaned up... It was black or sooted when I took it out.. YMMV.


https://www.garagejournal.com/forum/showthread.php?t=332512

Thanks for looking that up. I will take s look


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[Kaizen]

HY56 looks like a standard generic DPST.. double pole single throw...

Line side has hot and neutral and load side the switched hot and neutral... two switch in one... same as my craftsman one. pretty sure it's generic and typical for most power tools...


https://www.lumberjocks.com/replies/on/10541985

What’s throwing me off is I have another set of wires also attached to the line terminals. Do something in there is getting constant power besides the switched load.


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[Kaizen]

There should be a coil with 2 terminals.

Connect the terminals and you should be getting 120v on the output side of the contactor.

On the motor right?


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[dogdog]

What’s throwing me off is I have another set of wires also attached to the line terminals. Do something in there is getting constant power besides the switched load.


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I think it is easier if you break the troubleshooting down to sections... the switch / the motor/ something else... without knowing what your motor is... at least from the pictures...

The switch is a DPST... means its just two on/off switch in one... the line side of the one terminal should have continuity to the opposite load side of screw terminal when the switch is on... so continuity test/ohm test with everything off (just testing the switch, hope you have marked every wires) and /or physical inspection of the contact points if you are adventurous. but that is all to it...

Now what those extra set of wires you'll have to figure out if they are all going into the motor. If it is.... maybe ohm test the sets... Not sure without looking at it or poking at it...

more PICS of the motor or where that extra set goes ? maybe to a work light ? The one for my Jet Drill press goes to a work light. but that is only a 1/2HP... maybe some one hooked it up wrong ... it should have been on the Load side ? 1.5HP/2HP motor should have a start capacitor and start coil too ? does that extra set of wires (one of them) goes to the capacitor ? (just not sure if it should have been on the load side)... anything is a wild guess... me.... not sure ... just throwing more confusions at you but do break down your troubleshooting it makes it easier for you.

 

[BillK]

What’s throwing me off is I have another set of wires also attached to the line terminals. Do something in there is getting constant power besides the switched load.

Maybe a start capacitor ? Is the saw belt drive or direct drive ? Can you try spinning the motor by hand and see if it will run ? Put up a pic of the motor.

 

[Kaizen]

Maybe a start capacitor ? Is the saw belt drive or direct drive ? Can you try spinning the motor by hand and see if it will run ? Put up a pic of the motor.

Yea plan is to take the belt off today and try spinning it. Tight quarters so trying to not get hurt. Hence why I want to find where to constant is going to. Most likely a start capacitor


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[Kaizen]

Maybe a start capacitor ? Is the saw belt drive or direct drive ? Can you try spinning the motor by hand and see if it will run ? Put up a pic of the motor.

Switch tested fine. took off the belt. Spun it by hand and it ran with no load. Then shut it off and then on and it started on its own with no load. Added load and back to buzzing.
Time to pull the motor and start pulling it apart I guess. Thanks for everyone’s help


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[Kaizen]

Thanks dogdog. That’s the factory wiring. I bought this new and haven’t had it opened in the 20 years I’ve owned it. I will pull the motor to test the capacitors and go from there.


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[Bert_]

If the motor makes noise then the switch is fine. You need to be looking at the motor.

The suggestion to look at capacitors is a good one.

 

[Jim greengo]

Take a piece of wood and try spinning blade to see if motor takes off.

 

[BukitCase]

Bert's suggestion is likely the right one - @ 20 years old, there's a good chance BOTH caps are dried out. Decreased capacitance on the Start cap may not keep the motor from starting with just its OWN inertia, but the extra load of belt/blade would be too much for it.

Hopefully you can still read the markings on the caps; then the trick these days is finding caps that will actually fit in the cover AND not be too difficult to adapt the connections... Steve

Jim posted while I was typing; another good suggestion (especially about using a piece of wood, INSTEAD of a finger :=)

 

[Kaizen]

Take a piece of wood and try spinning blade to see if motor takes off.

No it won’t.


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[dogdog]

Thanks dogdog. That’s the factory wiring. I bought this new and haven’t had it opened in the 20 years I’ve owned it. I will pull the motor to test the capacitors and go from there.


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too many people already suggested the cap... feels like I am echoing so I delete. but yes it is odd that they precharge the caps.... if that extra wiring is for the starting circuit.. no personal experiences in this department to why... if anyone knows would be good for me to learn as well...

 

[BFBOB]

if that extra wiring is for the starting circuit..

Extra wires for an always-on convenience outlet?

I have a split convienience outlet on my table saw - one half always on, the other half switched.

 

[Kaizen]

Got the motor out. Extra constant voltage went to digital readout.
Here is the motor plate. 2hp. Have two capacitors. One marked starting capacitor tests fine. Then I have this thing that only goes to two ohms and does not climb. No markings on it at all?? I knocked the wires to test.


From what I have seen I should have a throughout bearing that engages with start capacitor and then centrifugal weights stop its engagement. Took off the pulley and case cover but only have this.

This is the other side. Did I take off the wrong side?



If that is a capacitor and it’s blown how do I get the specs to replace it?


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[Bert_]

Start switch is almost always in the back of the motor.

How did you test the capacitor? You can do a good/bad test with an ohm meter. No matter what test method you use the capacitor needs to have at least one lead disconnected.

 

[Kaizen]

Start switch is almost always in the back of the motor.

How did you test the capacitor? You can do a good/bad test with an ohm meter. No matter what test method you use the capacitor needs to have at least one lead disconnected.

So which side is the back?
I put leads on capacitor and ohm increased to infinity. I didn’t disconnect lead. You sure about that?


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[Bert_]

So which side is the back?
I put leads on capacitor and ohm increased to infinity. I didn’t disconnect lead. You sure about that?


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The side with the shaft sticking out for the pulley is the front. If you were able to get a reading with the capacitor in circuit then there is something wrong inside the motor. Either the start switch is stuck open or the winding is open.

Did you try the tried and true method of smacking the motor with a hammer? You laugh but many times that will unstick a start switch. If the capacitors are good I'll often try it.

Always gets a good reaction from the customer when the tool of choice to fix a motor is a hammer.

 

[bubinga]

The side with the shaft sticking out for the pulley is the front. If you were able to get a reading with the capacitor in circuit then there is something wrong inside the motor. Either the start switch is stuck open or the winding is open.



Did you try the tried and true method of smacking the motor with a hammer? You laugh but many times that will unstick a start switch. If the capacitors are good I'll often try it.



Always gets a good reaction from the customer when the tool of choice to fix a motor is a hammer.

Yeah I hit my old Craftsman table saw motor with a hammer and it started never had no trouble with it after that.

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[dogdog]

So which side is the back?
I put leads on capacitor and ohm increased to infinity. I didn’t disconnect lead. You sure about that?


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The ones with the fan blade is usually the back... in your pic, just take off that blade with a small hex key, you should be able to take it out... just be careful though that switch is like a flywheel... sort of.. might be tricky to re-assembly... was for me.

The start switch is same as the Centrifugal switch ("I think") , it should be normally close ( normally conduct ) and disconnects ( off ) when the motor spins to certain RPM.


You do normally isolate the capacitor to test... as any components attach to it might distort the readings, better to use capacitance settings in your multimeter. even better if you have one of those capacitance meter(LCR) or something with ESR capabilities... ... It's a good time to test your switch as well to see if it had continuity...as well as your start coil..

 

[Kaizen]

Well she is back humming along. I appreciate all of your help. This was my first time getting into motors like these and I definitely gained knowledge.
Turned out to just have sawdust packed into the throw out bearing which was preventing it from moving. No parts were damaged so I just cleaned it out well. Glad it’s fixed.


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[wyliesdiesels]

Have you considered some kind of dust collection system to keep the motor from sucking in sawdust?

 

[Kaizen]

Have you considered some kind of dust collection system to keep the motor from sucking in sawdust?

Yes it’s a hybrid cabinet saw that has a dust port. I use a stand alone dust collector but I don’t have power in the new garage yet so I haven’t been able to run both on cords along with lights. Like I said it’s 20 years old so could just be build up as well from decades of use.


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