# Switchng my Unisaw to 110v - what is all this stuff?



## RepairmanJack (Aug 4, 2013)

I've been using a 1983 Jet (Asian) Contractor saw for about 9 years now. This week I had a chance to pick up a Rockwell Delta Cabinet Saw for a decent price, so I jumped on it. It's now sitting in my shop, waiting to be hooked up. 

The Unisaw is 1973 model, great condition with a single phase, 2hp motor, but wired up for 220. We tested it for wobble and smooth running at the warehouse, so I know that it starts and runs ok. 

Trouble is, I don't have 220 in my shop, and there's no room in my panel to upgrade right now, so I want to downgrade the setup for 110v. 

I did the same for my old Jet via a small panel on the motor. Seems that it's usually just a matter of switching a couple wires. The diagram on the Unisaw motor shows pretty much the same thing

The issue is that this unisaw has some sort of gigantic breaker panel with a smaller sub-box that contains some sort of voltage transformer. These don't look original, and I'm not sure if the wiring setup can be configured to run at 110 - or if all this stuff is even necessary. This appears to be a very complex magnetic starter assembly. the brand Name is Arrow Hart of Hartford Connecticut. The push-button switch on the front is the same brand. My Jet is about 110x simpler than this. 










The wires from the motor and the switch are in terrible shape. Hard and crumbly insulation. I put some shrink tube on for now, but it's beyond help. I will get a replacement cord tomorrow. Th wires in the rest of the main panel, and the smaller box with a transformer in it, are all nice and intact, so maybe I'll be safe with some new cords. 

I have two questions: 

1) Where are the wires for the motor voltage - inside the motor?

2) Is all this "stuff" necessary if i am going to run this saw at 110v? Should I keep this setup, or buy a modern/safer replacement setup? 










One of the wires wasn't even hooked up to anything.


-edit-

Did I mention the sawdust? fine-fine dust inside of everything. breaker box, the connector box on the motor, the switch on the front.


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## Trav (May 30, 2011)

Looks like ya got a contactor or a motor starter there. Depending on the type of switch and how the motor is wired it is possible that it is necessary to have it. More info is needed to make that determination.


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## Dave Paine (May 30, 2012)

What is the nameplate amperage? This will be doubled if you attempt to run on 120V.

The motor should state if it can be wired to run on 120V. I would be surprised. It likely needs a 30Amp circuit, if the motor can be run on 120V.

The picture you show may be the guts of a magnetic switch, common for the larger table saw motors.


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## woodnthings (Jan 24, 2009)

*I run a lot of motors on 220 V*

Some are 3 HP with the contactor type magnetic switch and run on 20 AMP breakers. Others use just simple double pole, double throw switches on 20 AMP breakers. Those 220V motors draw about 8 AMPs, so a 20 amp 120 V setup would work.



If you can get inside the motor for a wiring diagram to show connections, line in and load, and rotation, that's all you'll need.Post a photo of the diagram if you find it OR go to OWWM or Vintage Machinery for a diagram of your motor. http://vintagemachinery.org/


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## Toller (Dec 30, 2007)

Looks like someone kludged up a starter; there is a 24v relay and a transformer. I can't really tell from your photos, but you might be better off ripping that stuff out no matter what you do.

2hp is normally about 2400w, so you would probably need to put in a 30a line to use it on 120v. (I am just guessing, and I can't read your motor plate) As long as you are putting in a line, it might as well be 240v.


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## RepairmanJack (Aug 4, 2013)

This is a 2 HP motor. The plate pretty clearly says it can run on 115










The current Amperage of the dedicated line for my table saw is 20a

I agree that this stuff looks a bit sketchy. With all the dust and bad insulation, I'm surprised it didn't catch fire when we ran it at the warehouse. 
Any recommendations on new "guts" for this starter setup? 

--edit--

Also, what I know about this saw is that it came from a former High School woodshop.


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## toolguy1000 (Oct 4, 2012)

RepairmanJack said:


> I've been using a 1983 Jet (Asian) Contractor saw for about 9 years now. This week I had a chance to pick up a Rockwell Delta Cabinet Saw for a decent price, so I jumped on it. It's now sitting in my shop, waiting to be hooked up.
> 
> The Unisaw is 1973 model, great condition with a single phase, 2hp motor, but wired up for 220. We tested it for wobble and smooth running at the warehouse, so I know that it starts and runs ok.
> 
> ...


blow out the saw dust with compressed air. get a few tandem breakers for your panel to free up space in the electrical panel. adding a 20A 220v line is not a big deal at all, if one has a basic understanding of electrical wiring.

and looking ahead to dust collection for your new saw, see that little square plate beneath the magnetic starter on the saw's base? that makes a great dust collection port, as long as a floor is placed at the bottom of the saw's base (that's the wood slats sealed with foil tape). here's how i did it on the '72 unisaw i sold. with the OEM dust clean out door on the front of the saw and the fabricated motor cover, a 4" hose connected to the dust collection port did a remarkably good job of clearing dust from the saw cabinet.


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## Alchymist (Jan 2, 2011)

NEC says 125% of motor rated full load current, in this case 30 amp minimum, and #10 wire. Might better throw in a new sub panel, and run 240 volts as suggested above. Would also leave some room to expand for the next tool to come dragging in. :thumbsup:


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## woodnthings (Jan 24, 2009)

*Just me*

But I would ditch that whole arrangement and use one of these: 
http://www.grizzly.com/products/110-220V-Paddle-On-Off-Switch/H8243

I like the large safety paddles and use them on many of my stationary power tools. It is a double pole swicth and will break both the hot and neutral wires, not necessary for 120 V, but a good safety feature. I use them on my router tables running 120 V and my table saws running on 220 V. I replaced a magnetic type switch on an import bandsaw with one also, just as you are wanting to do.

I can't read the 115 V diagram in your photo, but I would simply follow that and use run the wires from the "line to switch" as shown. I like to use 12 ga stranded wire and solder the ends or use crimped on spade terminals. Use a little silicon grease to prevent oxidation of the copper. Black is hot, white is neutral and bare or green is ground to the frame and the green grounding conductor on the plug wire. :smile:


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## RepairmanJack (Aug 4, 2013)

woodnthings said:


> But I would ditch that whole arrangement and use one of these:
> http://www.grizzly.com/products/110-220V-Paddle-On-Off-Switch/H8243
> 
> I like the large safety paddles and use them on many of my stationary power tools. It is a double pole swicth and will break both the hot and neutral wires, not necessary for 120 V, but a good safety feature. I use them on my router tables running 120 V and my table saws running on 220 V. I replaced a magnetic type switch on an import bandsaw with one also, just as you are wanting to do.
> ...


I've got a similar switch on my Jet. Are you suggesting that I can ditch the entire crazy-looking panel? My jet's wiring goes from the plug to the switch to the motor. That set up would be *highly* preferred here. 

I plan to go 220, but my panel is full. Already have double-pole switches everywhere that can take them. I can do household wiring, but I'm not ready to install a sub-panel on my own.

--edit--

Also... where are the connectors depicted on the motor plate?


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## woodnthings (Jan 24, 2009)

*YUP, ditch the panel*



RepairmanJack said:


> I've got a similar switch on my Jet. Are you suggesting that I can ditch the entire crazy-looking panel? My jet goes from the plug to the switch to the motor. That would be *highly* preferred.
> 
> I plan to go 220, but my panel is full. Already have double-pole switches everywhere that can take them. I can do household wiring, but I'm not ready to install a sub-panel on my own.
> 
> ...


Last question first. See on the right side 115 diagram where it says "line to switch" those go to the switch. the wires from the plug go to the other side of the switch. SIMPLE. See where it says .."to reverse rotation above" interchange T5 and T8 if that's necessary.


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## RepairmanJack (Aug 4, 2013)

toolguy1000 said:


> looking ahead to dust collection for your new saw, see that little square plate beneath the magnetic starter on the saw's base? that makes a great dust collection port, as long as a floor is placed at the bottom of the saw's base (that's the wood slats sealed with foil tape). here's how i did it on the '72 unisaw i sold. with the OEM dust clean out door on the front of the saw and the fabricated motor cover, a 4" hose connected to the dust collection port did a remarkably good job of clearing dust from the saw cabinet.


Looks pretty nice. I've got a galvanized sheet metal cover for the engine side, with a dust-port built in. I doubt it worked very well, considering the dust that was inside of every nook and cranny in the saw. I'm planning to setup something better than a shop vac as soon as get things sorted on this saw.


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## RepairmanJack (Aug 4, 2013)

woodnthings said:


> Last question first. See on the right side 115 diagram where it says "line to switch" those go to the switch. the wires from the plug go to the other side of the switch. SIMPLE. See where it says .."to reverse rotation above" interchange T5 and T8 if that's necessary.



Oh, I think get it now. I just change the wire-to-wire setup in the big square block on the motor itself. 

The jet has a small terminal panel with spade and fork connectors in the side of the motor, I was looking for something like that here - guess it doesn't exist. 

Thanks!

-edit-

this is the switch I put on my JTS-10

http://www.grizzly.com/products/110-220V-On-Off-Switch/H8238


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## WarnerConstInc. (Nov 25, 2008)

I think it would be foolish to abandon that motor starter. The top box looks to be a junction box, with a cap in it???

You will need a 30 amp 120v circuit, with appropriate size wire. 

I think it may be time to seriously consider a service up grade or the like.


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## jigs-n-fixtures (Apr 28, 2012)

I agree with Warner: keep the relay control, it was added as a safety feature. In commercial applications machines must deenergize on power failure and stay off until manually restarted. 

Regardless of how you get power to the saw you will need to run new wire. Either a 30-Amp @ 110-Volt, or a 15-Amp @ 220-Volt. The motors required amperage is listed on the name plate, and you should bump up by 15%, so at 110-Volts you will need 24 X 1.15=27.6-Amps, which means a 30-Amp circuit. 

Since you are running new wire get a 220-Volt circuit installed.


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## woodnthings (Jan 24, 2009)

*commercial applications require a safety switch*

The theory is, IF the power to the saw is lost due to a storm or other failure, the machine will NOT start up on it's own when the power is restored. This will prevent a piece in the machine from being thrown back or worse yet if the operator had decided to place their hands in the cutter path, they won't be injured. The chances of this happening are remote, and in a home shop all you have to do is turn the machine off...if you can find the switch in the dark. 
Ideally your lighting circuit and the machine circuits are separate! 
This would only be an issue if the whole shop lost power, it was night/dark and there was no available or backup lighting. I have no qualms about operating my machines without the magnetic switches although several in the shop have them. The paddle switch at hip level is all I need for an instant OFF. I often use mine that way instead of using my hand.

What you choose to do is up to you, but for a simplified solution, a manual switch will work.


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## knotscott (Nov 8, 2007)

A 20 amp circuit won't fly for a motor drawing 24 amps nominally. If the current circuit wire is thick enough gauge, and your panel can handle the amp flow, there's a slim chance you could add a 30 amp breaker to the circuit, but I'd definitely consult an electrician first. 

Best route....run 220v to it if at all possible. A 220v circuit will run at a much lower percentage of it's capacity....better situation, less voltage loss, less excess heat, quicker response.


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## toolguy1000 (Oct 4, 2012)

knotscott said:


> ....Best route....run 220v to it if at all possible. A 220v circuit will run at a much lower percentage of it's capacity....better situation, less voltage loss, less excess heat, quicker response.


but not more power. that motor will only deliver 2 hp in either 110v or 220v configuration.


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## Skiptooth (Mar 12, 2013)

If that motor nameplate doesn’t say TP or thermally protected anywhere on it you'll definitely need to keep that motor starter in place because it contains the thermal overload protection for the motor [Those two spring looking things in the middle of the motor starter]. If you rewire for 120V, you'll only need one in series with the hot conductor, but not the neutral. The transformer is the step down to reduce the line voltage to 24V for the starter's control circuit.


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## RepairmanJack (Aug 4, 2013)

Alrighty. You folks make a pretty convincing case. 

I checked my breaker panel this AM and it looks like I've got x2 220V breakers already. 

About 12 years ago, my father in-law (an electrician) installed a 30 amp 220v for us that services the 2nd floor (it splits into four 15a 110v breakers at a sub-box on the 2nd floor). 

I also have a second 220v breaker. This one is 50a with 8 gauge wire and that used to service our old electric oven. 

It looks like I can use this 220v position, (downgrade from 50a to 20A) and simply run my saw from this breaker location. I plan to eventually get some better-quality stationary tools, but for the moment, this saw is the only thing that needs 220v. 

I'll replace the cord & switch wiring in the saw, but I'll keep the Unisaw wiring setup the same.


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## RepairmanJack (Aug 4, 2013)

Just to give you all a little closure, I'll report what I've done. 

The saw's power was already on a dedicated 20-amp line, wired with 12/2 BX cable. In my breaker box, I switched out the old unused 50a 220 breaker for a 20a 220 breaker. I wired the saw's 20a line to the new breaker, and replaced the receptacle with a 20a/250v outlet. I also painted the white wire on both ends to indicate that it's now a "hot" wire. 

I kept the saw wiring at 220, and replaced the main plug cord with new 12/2 (3 wire) cable. I also replaced the wiring from the magnetic switch to the on/off with new 12/3 (4 wire) cable. I replaced everything wire-for-wire. The setup is exactly as it was when I checked it out at the warehouse. 

I plugged in the saw, switched the breaker on, and pressed the on switch. The saw fired up and started humming nicely. 

Thanks for the advice. Wiring up 220 was way easier than I thought. Seems that I've done this before, but I didn't realize that it was the same thing that I did for the electric oven. 

I've got more questions (including the persistent problem, note below) but they don't necessarily relate to the 110/220 question that started this thread. 

---
There's a new problem. After putting the top back on, the saw starts up, but switches off as soon as I release the "on" button. I need to investigate this further. If I hold the button down, it hums along. Dies as soon as I release.

At the moment, I'm thinking that it's either the switch itself or the overly-complicated magnetic switch assembly on the back.
---


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## jigs-n-fixtures (Apr 28, 2012)

The magnetic starter should be locking in, until the stop button is pushed which opens and breaks the hold in current. 

Check that the stop button is actually closed


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## RepairmanJack (Aug 4, 2013)

jigs-n-fixtures said:


> The magnetic starter should be locking in, until the stop button is pushed which opens and breaks the hold in current.
> 
> Check that the stop button is actually closed



I was just fiddling with it before stopping from the night. Pressing the stop doesn't seem to do anything. I can feel the magnetic switch causing the motor to cut-out. I'll look into it further tomorrow. 

Otherwise, I've got the saw in place, the top has been cleaned up and polished with paste wax, and I've got my VSCTools beisemeyer style fence installed.


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## RepairmanJack (Aug 4, 2013)

Ok, I've done a little more investigation and have determined that it's something with the magnetic switch assembly and/or the transformer. 

The switch on the front is a heavy-cast metal momentary switch - almost nothing there to go wrong. The "on" button briefly bridges the Red to the Black & White wires and energizes the magnetic switch on the back. The "off" button breaks the connection between the Black and White wires to de-energize the magnetic switch. 

The problem is that the magnetic switch stays off unless I hold down the momentary switch on the front. I can run the saw by holding the magnetic switch closed or by holding down the On button on the front. 

What is odd, is that I changed nothing and it stopped working. After replacing the rotten 4-wire between the front and back, the saw started and ran nicely, until I shut it down with the stop button. Since I put all the covers back on and parked it in the "place of honor" in my shop, it has refused to run. 

My working theory is that "reset" mechanism is jammed somehow. There's a surface mechanism on the magnetic starter panel. Plastic with some some of pin that pushed a large reset mechanism inside the panel. It has almost no travel, so perhaps it was pushed down too hard when I was parking the saw up against my workbench.


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## TimPa (Jan 27, 2010)

did I miss what you did with the previously un-connected wire? 

as mentioned, your relay is not "pulling in" to latch ON your contacts, this would be your 24vac coil control circuit that needs attention. or it is pulling in then releasing??


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## RepairmanJack (Aug 4, 2013)

TimPa said:


> did I miss what you did with the previously un-connected wire?
> 
> as mentioned, your relay is not "pulling in" to latch ON your contacts, this would be your 24vac coil control circuit that needs attention. or it is pulling in then releasing??


Yeah, thanks for reminding me. I mentioned that the panel was *full* of sawdust. When I cleaned it out, I found a little brass screw-down contact. The contact fit perfectly where the loose wire was hanging in front of the contact, so before I did my first test-start, I reconnected the wire. 

Here a photo of it all re-assembled








(basically, I borrowed the unused contact screw from the left side)

For the other issue, the magnetic switch is being pulled shut when I press and hold the On switch. It just releases as soon as I release the momentary switch on the front. 


--
In a nutshell, it's pulling in, then releasing. 
--


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## FrankC (Aug 24, 2012)

RepairmanJack said:


> Alrighty. You folks make a pretty convincing case.
> 
> I checked my breaker panel this AM and it looks like I've got x2 220V breakers already.
> 
> ...


You will be much happier running the saw on 220, the comparison looks great on paper but there are catches to using 110.


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## RepairmanJack (Aug 4, 2013)

FrankC said:


> You will be much happier running the saw on 220, the comparison looks great on paper but there are catches to using 110.


Well, downgrading to 110 "sounds" like the easier option, but clearly not. An under-powered circuit is likely why my 110v-configured Jet would cut out on me when making heavy-duty cuts in thick stock. 

Now if I could just get the unisaw started and running reliably...


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## TimPa (Jan 27, 2010)

RepairmanJack said:


> Yeah, thanks for reminding me. I mentioned that the panel was *full* of sawdust. When I cleaned it out, I found a little brass screw-down contact. The contact fit perfectly where the loose wire was hanging in front of the contact, so before I did my first test-start, I reconnected the wire.
> 
> Here a photo of it all re-assembled
> 
> ...


as I mentioned, the coil ckt needs ts. it appears that you reconnected the previously loose wire to one end of the coil, while borrowing a screw from the contact for the other end. there needs to be 24vac on the coil connections while the on button is depressed, and it takes 2 wires to accomplish that - one on each "to coil" screw terminal. do you have a voltmeter and know how to use it?

fyi... the top half is the contactor/relay portion, and the bottom half of the device is thermal overload (OL) heater protection = motor starter.


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## RepairmanJack (Aug 4, 2013)

TimPa said:


> as I mentioned, the coil ckt needs ts. it appears that you reconnected the previously loose wire to one end of the coil, while borrowing a screw from the contact for the other end. there needs to be 24vac on the coil connections while the on button is depressed, and it takes 2 wires to accomplish that - one on each "to coil" screw terminal. do you have a voltmeter and know how to use it?
> 
> fyi... the top half is the contactor/relay portion, and the bottom half of the device is thermal overload (OL) heater protection = motor starter.


Thanks, I've come to the same conclusion after some more investigation. 

I had everything disconnected at the breaker box and from the receptacle and examined this whole assembly much closer. I removed the front part of the setup and checked out the magnetic contacts. Lots more sawdust back there. I reassembled it all and tried again, no change. I *did* notice a bit of a buzz coming from the transformer/coil, after when it was all switched back on. 

I'm wondering if this thing is the problem... 

I've got a voltimeter and know how to use it for automotive work. Testing grounds, voltage output, etc. 

Also, for reference, here are the diagrams from the inside cover of the saw. 

Magnetic Starter









Switch









I seem to have something close to the 2-pole single phase for the magswitch, and the "start-Stop 3-wire remote"

The screws on the magswitch are coded, so I put the borrowed "C-1" screw back where it belongs on the left side. 

I tried following the diagrams and the only differences I could see are that the C1 wire from the switch detours directly through the coil and that the C2 and C3 wires seem to be reversed at the remote switch. I tried switching the C2 and C3 wires, but got nothing at all.


--edit--
Also, there was no evidence of a second coil wire in there that would have been attached to the left side.


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## toolguy1000 (Oct 4, 2012)

RepairmanJack said:


> ........ I *did* notice a bit of a buzz coming from the transformer/coil, after when it was all switched back on......


this is totally normal. that's the humming you hear. when the plug is inserted in the wall receptacle, the transformer in the starter is energized. the transformer provides the low voltage current that is used in the starter switch circuitry to energize the relay that sends 220v from the wall outlet through the starter to the motor. it was also one of the reasons i sold the unisaw i refurbed. the idea of drawing current when the saw wasn't in use didn't sit well with me.


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## RepairmanJack (Aug 4, 2013)

This transformer is necessary for normal operation? Dang. It looks like a cheap add-on, bolted to the top of the magswitch box to solve some sort of past problem. It has about 4 extra, unused wires coming from it, and the fit inside the box looks accidental at best. The wires connecting it to the AH-32 magswitch are solid 12ga household wires. I see this AH-32-132 switch for sale by itself, but to function normally, it requires some sort of add-on transformer?


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## RepairmanJack (Aug 4, 2013)

OK, so I disassembled the magswitch and found the contacts were a bit scorched, so I removed all the contacts and cleaned them thoroughly with 1000-grit wet/dry sandpaper until they were much cleaner. I also added proper fork terminal ends to the all the new wires. I also cleaned up the magnetic contacts on the bottom of the switch itself. 

After reassembly... no change at all. 

I also tried routing wires to the other coil terminal and either the saw did nothing, or I still got momentary function.

I found a thread on another site that described almost exactly the same problem resulting from some sort of adjustable switch. 
I haven't found anything that looks like an adjustable switch on this saw. 

Getting discouraged here.


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## woodnthings (Jan 24, 2009)

*I all else fails*

Get one of these: http://www.grizzly.com/products/Magnetic-Switch-Single-Phase-220V-Only-2-HP/G4572

In your case, there may be a heater circuit that is adjustable for different starting loads. I just remember something about this in another thread.


http://www.sawmillcreek.org/showthread.php?130818-Magnetic-starter-3-wires-or-2


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## toolguy1000 (Oct 4, 2012)

RepairmanJack said:


> This transformer is necessary for normal operation? Dang. It looks like a cheap add-on, bolted to the top of the magswitch box to solve some sort of past problem. It has about 4 extra, unused wires coming from it, and the fit inside the box looks accidental at best. The wires connecting it to the AH-32 magswitch are solid 12ga household wires. I see this AH-32-132 switch for sale by itself, but to function normally, it requires some sort of add-on transformer?


what's the voltage of the control circuit? could the transformer mounted atop the magnetic starter been placed there to function for a defective transformer inclusive starter (the part that sits above the relay)?


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## RepairmanJack (Aug 4, 2013)

toolguy1000 said:


> what's the voltage of the control circuit? could the transformer mounted atop the magnetic starter been placed there to function for a defective transformer inclusive starter (the part that sits above the relay)?


24v, according to the labeling on the magswitch. The transformer looks pretty generic, so you might be on to something about this being a fix for a defective magswitch. 

I'd really like to make the original setup work, but at the moment, I have a very fine saw that does nothing useful. All my woodworking projects are on hold until I determine if this Unisaw can replace my old jet. 


These grizzly mag switches, would this completely replace the AH32 that I've got right now? I'd be willing to drop $70 if it would make my saw "work" without substantially compromising my safety. I could always come back to the original switch later.


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## woodnthings (Jan 24, 2009)

*I certainly think so*



RepairmanJack said:


> These grizzly mag switches, would this completely replace the AH32 that I've got right now? I'd be willing to drop $70 if it would make my saw "work" without substantially compromising my safety. I could always come back to the original switch later.


A quick call to Grizzly tech should give you that answer. AND they will come with a wiring digram which will certainly be helpful. :yes:


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## TimPa (Jan 27, 2010)

RepairmanJack said:


> 24v, according to the labeling on the magswitch. The transformer looks pretty generic, so you might be on to something about this being a fix for a defective magswitch.
> 
> I'd really like to make the original setup work, but at the moment, I have a very fine saw that does nothing useful. All my woodworking projects are on hold until I determine if this Unisaw can replace my old jet.
> 
> ...


although the status of your starter is unknown, it is likely not yet wired correctly. until then, i would not recommend a new starter. 

i can't see enough of the terminal labels in the pics to see what wire(s) are missing, especially the back terminals. from what can be seen the coil is not yet wired up. the transformer secondary (output) 24vac should be read at the coil terminals when the ON button is depressed. 

this box has 240vac inside, do not proceed if you do not feel comfortabe or capable doing so, get professional assistance.


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## dodgeboy77 (Mar 18, 2009)

Jack,

After thinking on this, the saw is acting like the normally closed 'off' switch button is staying open. Or one of the wires from it is disconnected. Someone correct me if I'm wrong, but if there was a break in the 'Off' switch circuit, isn't this how the saw would act?

Bill


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## TimPa (Jan 27, 2010)

yes, that was mentioned in post 22. but you're right.


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## RepairmanJack (Aug 4, 2013)

Ok, I've looked over the Magnetic Starter info over at OWWM. I can report partial (though temporary) success. 

Here's what I posted.

--
I've read up, tried couple things... had it working briefly, but it quit working again. 

The long and short is that the fat Red wire on the front is the momentary power from the "Start" button. White and Black wires are supposed to be constantly bridged at the front switch until the "stop" button breaks the contact. 

Looking over the wiring diagram and the coded machine screws (C1, C2, C3), I finally realized that the White wire (C1) was connected to the front terminal marked C2, while the black wire (routed through the transformer) eventually connected to the 3rd coil terminal (right above "CY 50-60" on the front of the coil.

Although I have "before" photos and know for sure that the fat Black wire was originally going through the coil, I followed the wiring diagram and swapped the black and white wires. Routing C2 (Black) to the front, and routing the C1 White wire through the coil, I hooked up the saw and was treated to it starting and then running after I removed my finger from the "Start" Switch. 

I switched it off and on twice with normal function. 

And then it went back to "normal" (not working). Again, it doesn't work unless I hold the Start button down. 


This is pretty much what happened when I first replaced the crumbling wire. It worked fine, once or twice, then the magnetic switch stopped staying closed. 

Unless the transformer or coil is intermittently defective (or I'm burning something out), I've really no clue why it "works" and then doesn't "work"
--


I'll add that there are two skinny red wires coming from the back of the contactor. On connector to the momentary (fat red), while the other connects to "C-9" (which has a C1 screw in the photo).


---
TimPa may be right that there's another wire to the coil missing here.
---

I'll also note that from the panel photo above, if I switch the red and white wires, the saw runs until I pull the cord or hold the "Stop" button down (breaking the connection between Red and White...


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## Alchymist (Jan 2, 2011)

Have you verified the coil voltage? If it's not 240, and an external transformer is used it should most likely be wired as shown below. If it uses a 240 volt coil, then the other drawing is the one to use. In either case note that the set of normally closed contacts next to T1 are thermal contacts, and could be worn/dirty where they make intermittent contact. Also note than if the transformer diagram is appropriate, the jumper at (x) next to C9 is removed. Troubleshooting from pictures is difficult, but the diagrams should give you something to go on, IF they match your starter.


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## RepairmanJack (Aug 4, 2013)

Thanks for the detailed connector mark-up diagram. I *think* that's the setup that I got to work earlier today. 

The coil is marked as 24V (which jibes with presence of the transformer) but I haven't put my multimeter on it yet. My wife drafted me to help her make a batch of beer, so I didn't get back down to check the saw again. 

Following the switch diagram
C1 is the fat white wire on the front
C2 is the fat black wire on the top
C3 is the fat red wire on the front


There are no jumpers that I recognize, but disconnecting C9 would be putting it back to how I found the switch when I first opened up the starter panel. I assumed that the screw was loose and ended up in the shop-vac .. will look into it further.


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## dodgeboy77 (Mar 18, 2009)

Jack,

A simple suggestion and maybe you've done this already, but have you put an ohmmeter across the terminals of the 'Off' side of the magnetic switch to make sure it has consistent continuity? Any break in that switch or the circuit to it could be causing the problem.

Bill


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## RepairmanJack (Aug 4, 2013)

dodgeboy77 said:


> Jack,
> 
> A simple suggestion and maybe you've done this already, but have you put an ohmmeter across the terminals of the 'Off' side of the magnetic switch to make sure it has consistent continuity? Any break in that switch or the circuit to it could be causing the problem.
> 
> Bill


Sometimes simple is good. 

I had the entire assembly out for inspection and cleaning. All the wires check out with good continuity, but the terminal on the front of the switch were not registering as open or closed. I took the clear face off the coil and checked the contacts. Again, nothing when I closed them. 

I found more fine sawdust behind the terminals, so I cleaned them out further, lightly polished the contacts and re-assembled. 

Now I get good solid continuity readings across the terminals. 

It's getting late, so I'll have to hold off until tomorrow to get the magnetic switch and transformer back in place. 

I'll cross my fingers that this was part of the problem.


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## RepairmanJack (Aug 4, 2013)

Alchymist said:


> Have you verified the coil voltage? If it's not 240, and an external transformer is used it should most likely be wired as shown below. If it uses a 240 volt coil, then the other drawing is the one to use. In either case note that the set of normally closed contacts next to T1 are thermal contacts, and could be worn/dirty where they make intermittent contact. Also note than if the transformer diagram is appropriate, the jumper at (x) next to C9 is removed. Troubleshooting from pictures is difficult, but the diagrams should give you something to go on, IF they match your starter.


wanted to note that the diagrams you've connected up are helpful, but for some reason the saw was not wired in accordance with the diagram. No real idea why, but the wires were just routed differently. 

My transformer had two wires going to the 110vac trunks, another to the coil, and one to the momentary switch on the front. 

I'm not sure about the wiring on the transformer, or how to get it right.


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## Alchymist (Jan 2, 2011)

Perhaps this way?


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## RepairmanJack (Aug 4, 2013)

Alchymist said:


> Perhaps this way?


That appears to be very close to the original setup. exception was that the transformer wire was attached to the left of the coil, rather than at C9.

I'll try it our when I get home. 

Hopefully it was actually wired correctly to start with and the problems were due to corrosion on the front contacts. 

If so, I'll be ready to "dance" in the street. 

Will report back as soon as I get it tested. 

Thanks again for the diagrams.


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## RepairmanJack (Aug 4, 2013)

*It's Working!*

I reassembled all the magnetic starter components. Cleaned and checked wire continuity with my Multimeter. There's no more sawdust in the crevices. I put good terminal ends on all the wires, replaced anything that looked rotten or crumbly, and wired everything back up.

I pressed my "Start" button, and she hummed to life... and kept running after I released my finger. She switched off when I pushed "Stop" and functioned normally for several extended tests. 

Seems that the problem was bad contacts on the front of coil. A continuity test of the front screws revealed the problem. :thumbsup:

Thanks for sticking with me, while I learned how one of these mag switches work, and why I needed one. 

Now I just need to get my shop configured for this monster new saw...


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## woodnthings (Jan 24, 2009)

*congratulations!*

If you didn't manage to fix this, you were gonna have to change your user name to unclejack or some other name that didn't involve repairing anything ..... :blink: :yes:


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## toolguy1000 (Oct 4, 2012)

congrats on the fix!

but am i correct that it ceased operation because you removed wires and didn't get them reattached correctly, and that this was compounded by, or caused by, bad contacts on the front of coil? just curious.


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## dodgeboy77 (Mar 18, 2009)

Great work!


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