Unisaw magnetic switch hookup

[dwieland]

I got a 1980s vintage Rockwell Unisaw on the weekend but haven't been able to properly connect a power cord. I test-wired the motor (110V 1.5hp) directly and know it works. But the proper connection of the magnetic switch eludes me. The pushbutton switches, motor terminal block, and contactor are all in a box with a clear cover that holds the power buttons and which was easy to remove by turning the two lock buttons on the cover. Inside though there's no clear indication of where the previous power connections were made. Only two terminals are marked, as far as I can tell, T1 to the motor and one of the red wires (labelled L1) on the DIL 0-11. Here are pictures of what I'm looking at:

https://picasaweb.google.com/ddwieland/Rockwell34450Unisaw02?authkey=Gv1sRgCIfluPvbxvKAuwE

The yellow twist-ons are capping the power cord leads (except the green ground that's connected to the ground screw). There are a couple of pigtails I used to test connecting to the T1 and L1, since they are the only labelled terminals. Pushing the start button made the relay chatter but didn't power the motor. Based on what I've read on forums, I also tried connecting to L1 and the terminal beside it, assuming it's L2. Nothing at all from that arrangement.

The Klockner-Moeller DIL 0-11 has been superseded, there's no wiring diagram on the tool (because of the clear cover?), and I haven't found hookup info on the web. Can anyone tell what else I should try? Judging by the relay chatter from the first test, I don't have reason to suspect the contactor is dead. But what terminals make sense to connect?

David in Ottawa

 

[MTW]

David I'll try to help. I know motor controls quite well, but am not familiar with your particular motor starter. klockner Moeller is a well known German brand but not very popular in my area, usually only see it on imported machinery. The part number you gave is for the contactor (3 pole) only, it's not the number for the entire starter assembly. Is there a number for the assembly on the outside of the enclosure?

Find an example contactor here.
http://www.ebay.com/itm/MOELLER-DIL0-11-NA-Universal-Contactor-600VAC-DIL-0-11-NA-DIL-011-NA-DIL011NA-/281243569993?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item417b6c4f49

On most starters the power enters in the top terminals of the contactor, exits the bottom terminals and then go's on to the overload relay. The overload relay is the brown unit to the left of the contactor. And then on to the motor.

T1,T2 is equal to the motor connections. L1,L2 would be the power connections. Small red & white wires are control circuit wires, large black wires are the motor circuit.

It appears from the photo and the ebay photos that you have a three phase starter converted for single phase operation. I couldn't see all of the wiring and terminals to fully discern your condition. More photos at different angles, with all temp wires and wirenuts removed to clearly see all component connections.

On the top of the contactor and the left side of the overload relay, there are black jumpers installed to parallel connect L2, L3 and series connect T2,T3 terminals, this was done for the 3 phase to 1 phase conversion.

If I had to guess from what I can see power supply leads would go to the top of the contactor. 120V Hot to the same terminal as red L (L1). 120V Neutral would go to the next terminal to the right, (L2,L3) where the black jumper is.

A few other things. Is the motor 1.5HP 120V only or 120/240V ? 1.5HP@120V at full load is likely to trip your average 20A 120V circuit under full load if your not very close to a panel. Does the machine nameplate state the voltage that the it's setup for? On the contactor coil is a tape label with the coil voltage, is this 120V or 230V?

Here's a similar overload relay to yours.
http://www.ebay.com/itm/Vintage-Klockner-Moeller-ZO-Series-Thermal-Overload-Relay-0-21-Amps-Circa-1968-/221411724388?pt=LH_DefaultDomain_0&hash=item338d2acc64

 

[Norcal]

That K-M starter was most likely a aftermarket item, Rockwell used a proprietary starter they called "LVC" Low Voltage Control, comprised of a multi-tapped 120/208/240/480V control transformer to supply 24V, a contactor & overload relay, the angle of the photo supplied makes it hard to decipher it + some of the old IEC starters are weird.

 

[mm08822]

David as MTW stated, better pics are needed to trace out the circuits. If you could remove the pigtails and get the supply leads out of the way and then take pics:
from top side of contactor (black),
bottom side of contactor,
in between contactor and overload relay (brown),
top of pushbuttons,
bottom of pushbuttons,
the starter cover- inside and out
and motor nameplate.

Based on your one photo, it looks like L1 gets the black from your 110v supply and the white in the starter gets connected to your 110v neutral. (This last point is different than MTW’s input. MTW, I think they series connected all three poles of the contactor with the three o/l poles, so the o/l would work properly.) Don’t hook up any power until we can review the new pics.

The pulsing of the coil is typical of a low voltage condition or a contact in the control circuit is opening as soon as the coil is pulled in. So confirming the coil voltage is important - the new pics help here.

I doesn't look like a stop button is wired in to the control circuit - both look like normally open contact blocks from the part numbers– the stop pushbutton is usually a normally closed. So this could be set up as 2 wire control and not 3 wire control. New pics will help determine the type of switches - momentary or maintained.

The overload reset is set to "auto" mode. You may want to change that to "hand" for personal safety – especially if it is 2 wire control with maintained switches.

 

[dwieland]

Thanks for the help. There's no label on the outside of the enclosure, but there is one just below what I think is the thermal overload. I've edited my initial post to point to more and better pics, so you can see it there. It's partly obscured by wires, so if you think it would be helpful, I'll post a full close-up.

This came from a school shop, so if the original switch wasn't magnetic, this one must be an after-market replacement.

I thought I'd be sawing wood by now, instead of messing around with wiring up the sucker, but life's full of surprises. I'm learning about power tool mag switches, but maybe I should just go for a simpler new one like this: http://www.grizzly.com/outlet/110V-Magnetic-On-Off-Switch/H8240.

 

[mm08822]

Top view shows 120v coil rating. I can't trace the wires between contactor and o/l to be sure how it has been wired....still need these pics:
bottom side of contactor,
in between contactor(black) and overload relay (brown) pull reds aside,
bottom of pushbuttons,
the starter cover- inside and out

 

[dwieland]

I added a pic from slightly below the box (about as low as I can go without lying down) that should clearly reveal more connections. As I mentioned in the initial post, the cover is clear (except for the red and green buttons), so there's no info on it. If that's not what you meant by "the starter cover", you'll have to describe it to me.

I really do appreciate the interest and efforts to help.

 

[MTW]

dwieland, here is your solution, a connection diagram, for the setup in question.
As I stated earlier, 1.5HP on 115V is pretty iffy for reliable operation, especially at full load and startup. You wont be able to utilize the full horsepower on a normal 20A 115V home circuit, its only rated for 16A for maximum motor loads. By code the minimum would be 25A (20Ax1.25), 30A would be better and won't exceed code maximums.

Here is a view of just the components in a layout view.
Full resolution https://dl.dropboxusercontent.com/u/13118477/Electrical/Components.jpg

Here is the 120V control wiring only, for simplicity, power connections omitted.
Full resolution
https://dl.dropboxusercontent.com/u/13118477/Electrical/ControlWiring.jpg

And here is the complete drawing for 120V connections
Full Resolution
https://dl.dropboxusercontent.com/u/13118477/Electrical/120VConnection.jpg

Take a look at what you have, it should match the drawing, if there are discrepancies let us know, we'll try to steer you the right way. This starter and motor could be converted for operation at 230V to achieve the full output of the motor, if you find that necessary in the future. To do that, you would need a 230V circuit with a neutral and ground to power the 120V coil on your contactor. In that case a 15A 230V 1Φ 4W circuit would be required, to give you the full output.

Let me know if that is something you are interested in doing and I could make a revised drawing for a 230V connection.Ω

Contactor Ratings, Courtesy of Ebay

 

[dwieland]

Wow, that's impressive, MTW! Unfortunately, the neutral connected to white wire's left side terminal doesn't seem to work. With the hot input on L1, when I push the start button, the relay just chatters and the motor budges a little. Does this suggest a problem with the contactor itself?

 

[mm08822]

MTW drew out exactly what you need. I was trying to confirm if you had all the hardware needed and how it is wired. Hopefully you were able to confirm this.

Let's take the stop/start button and o/l out of the circuit. Connect a jumper from L1 directly to the hot side of the contactor coil. The motor should run once you connect the jumper to those points. If all was working properly, it would stay running after you removed the jumper and would require hitting the stop button or unplugging the power cord. Let us know your results.

 

[MTW]

Wow, that's impressive, MTW! Unfortunately, the neutral connected to white wire's left side terminal doesn't seem to work. With the hot input on L1, when I push the start button, the relay just chatters and the motor budges a little. Does this suggest a problem with the contactor itself?

To me it suggests a problem with your supply circuit capacity as suggested earlier. When you try to start the motor, the supply voltage sags so bad that the contactor starts to drop out from low voltage. When it drops out, the voltage then rises and starts the cycle over again, causing the chattering of the contactor. To verify this is the issue, disconnect the motor leads. With the motor leads removed the starter should work normally. If it does, and the motor starts on a manual test as you stated previously, then the problems lie with the supply circuit, not enough capacity for starting at 115V as suggested earlier. Try moving the saw to a circuit closer to the main panel if possible, for less voltage drop Give it a go and let us know how you make out.Ω

 

[dwieland]

That sounds like a good test, bypassing intermediate components. But where exactly is the hot side of the contactor coil? Is it the terminal in line with L1 but on the underside of the coil (below left end of the white sticker with the number 1231132)?

 

[dwieland]

Well, I think you nailed it. It's pretty hard for me to move the saw closer to the panel right now, but I used a short, heavy-gauge extension instead of the lighter one I had been testing with. With the motor disconnected, the contactor works as it should with the start and stop buttons. With the motor reconnected, pushing the start button caused the motor to run briefly. I need more voltage!

Now I can take the motor off the saw to lighten it enough that I can haul the parts downstairs to my shop. There it will be a few feet from the panel and should run continuously. I think switching to 230v is a good idea, but wouldn't I need to replace the coil with a 230v one? K-M parts seem pricey, but maybe it would be money well-spent. It does puzzle me that the current setup worked in a school shop, but it must have been wired in with conduit.

 

[MTW]

For the existing 120V setup, you need a 30A circuit for the full rated output of the motor. Not a very common occurrence, but is doable. 30A 1Pole breaker and #10AWG wire would do it. Running on low voltage (115V) is harder on the starting of the motor, start switch and capacitor. Running on 230V would make the motor last longer and start with less stress.

As stated previously, you would not need to change the coil voltage if you ran a 4 wire supply circuit. The extra wire for the neutral would be required just to power the 120V coil. If that's something you want to do, it will require some modifications to the existing diagram / starter. Let me know and I'll try to make time to revise the diagram for you. The main problem with converting this starter to 230V is the overload relay. It's adjustment range was 16-24Amp, for 230V operation you really need the adjustment for the 10A full load current of the motor at 230V. Turning it down to the minimum 16A won't protect the motor windings, and may result in a burnt motor or fire if overloaded or stalled. I think that this vintage overload may be hard or expensive to source in the range that you need, I'll leave that up to you to seek it out. You may also keep an eye out for a used starter with the buttons, 10A overload relay and a 230V coil. Might be easier or cheaper to source and just replace the whole shebang.

Glad to hear you figured it out. Can we change the unhappy icon now? Ω

 

[dwieland]

Glad to hear you figured it out. Can we change the unhappy icon now? Ω

Yes, we certainly can! You and mm0822 deserve a big thumbs up for the help. At the start of this process, I just wondered what terminals to hook the darned power cord to. Now I know it was worth the frustration to have the chance to learn some important things. I'll decide on switching to 230v after the saw's set up in its proper place and I can do some actual sawing with it.

Thanks much!

 

[mm08822]

Good to see you located the problem. I wasn't sure you had a functional unit to start with and may be finishing someone's old school project. Being there provides extra input to understand all of the conditions - seeing actual wiring, lightweight supply cord, etc.

As MTW stated, you need a new 110v or 230v circuit to eliminate the voltage drop. Glad to see you chose the 230v option.There are more benefits to you with the 230v option for long term – full hp available if needed, up to speed faster, most important - generate less heat in the motor and is a common circuit. You could use this receptacle for other future 230v tools.
I recommend installing a 230v circuit with 20A 2 pole breaker, 12-2 romex (or other 12 ga. method), nema 6-20 plug/receptacle. This requires a new starter with 230v coil with o/l range covering 10A and reconnecting the motor for 230v at the motor. Don’t let the cost of the new starter sway you towards the 110v option.
Happy sawing!