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  #1  
Old Sat 07 July 2007, 12:27
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Mains power wiring

Following on from this archived thread, here are suggested mains power schematics. All the disclaimers and safety warnings apply. These circuits probably do not comply with your local health & safety laws - use entirely at own risk!

The first sheet, 10 60 105 C A, shows the simplest of circuits which will cut wood just as well as any of the more complicated circuits. But it won't give you safe Emergency Stops or control of the router from Mach3. The unscreened router cable might radiate electrical noise into exposed control signal wires - avoid this by keeping cables far apart and/or screening the control cables.
Attached Files
File Type: pdf MainsPowerSchemes.pdf (927.9 KB, 463 views)
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  #2  
Old Mon 06 August 2007, 19:17
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Gerald or Mike, or who-ever,

Would you mind checking my wiring for the contact and the on/off switch in the attached schematic. My contact is a Teco CN-22(4P). I just don't get the current flow when the "on button" is closed. It just seems like everything is a short. How does the coil (A1 and A2) get energized without frying everything

Greg

MM1 8 7 07 Model (1).pdf

Relevant part of Greg's diagram below:

Circuit.gif
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  #3  
Old Mon 06 August 2007, 23:33
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Why do you say everything "is a short"? Did you get sparks/smoke/dark neighbourhood, or are you measuring zero resistance? Shorts are serious, life threatening things and make me wish that I had never shown any schematics!
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  #4  
Old Tue 07 August 2007, 06:12
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Gerald,

You misunderstood what I posted. I Posted "it just SEEMS like everything is a short". Just on paper, no fires, no lights out, no blown fuses on my end. If your worried about someone causing harm from the electrical side, what about the mechanical aspects? The persons who is strong on the electrics, will say that welding, cutting metal worries them. The person who is strong on the mechanicals, will say that the electrics scare them. All aspects of this project require sound, safe, practices and a complete understanding of all components. Trust me, I still have all my fingers and no wound scars. One of my first lessons when entering a new machine shop with a project, was to look at the operators hands. I would avoid the operators with missing fingers. Maybe a dedicated thread/section on safety is in order. I have read several posts with very good links to grounding, etc, but no thread specifically dedicated to mechanical and electrical safety.

Anyways, I'm just at the point of wiring the contactor and on/off switch, along with the E-stops, etc. Before I actually take the electrical plug and put it into the wall, I want to make darn sure, I understand the current flow. When the on contact is closed, current flows thru one leg of the 115 VAC, to the 1 amp fuse, thru the sheilded cable and to the NC off button. After the off button, one path goes thru the closed on button, to the lamp, and energizes the coil. The circuit is complete and were happy.

The path I don't understand is after the off button (just left of the off button in my previous posts attachment), current can flow to 5L3 to 6T3 to the on button to that same point. Making a complete circle. Well, now that I'm writing this, that path is not a complete circuit. Current will flow thru 5L3/6T3, to the on lamp, thru the coil to the neutral leg and make a complete circuit. Would that be a correct statement?

Greg
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  #5  
Old Tue 07 August 2007, 06:50
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
When you said "I just don't get the current flow when the "on button" is closed" I read it as "I just don't get the current to flow when the "on button" is closed" forgetting that you guys tend to use the word "get" and "understand" interchangeably. I had the clear message that you had actually pushed the button and either nothing or something bad had happened. To all intents and puposes we are speaking a common language "english" but the meanings and intents have differences. When you ask "Would that be a correct statement?", my answer would have to be "I don't know", because I could not know for sure if I am interpreting your words with the same meaning.

Consider the On Button and the 6T3/5L3 contact to be parallel switches. The On button moves the core of the contactor and the 6T3/5L3 holds it there after the On Button is released. This is the "latching" we talk of.

If you want to be safe at the first switch on, prod it with a stick while you close your eyes!
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  #6  
Old Tue 07 August 2007, 07:08
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
If it helps your understanding, remove the lamp and connect 6T3 direct to A2. ie. consider the lamp blown.

Play with what-ifs, like above, and see if you get a clearer picture.

What if 6T3 was disconnected?

What if 5L3 was disconnected?

What if 6T3/5L3 burned permanently closed?

Etc.
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  #7  
Old Tue 07 August 2007, 07:13
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Thanks Gerald,

I like the idea of closing my eyes and prodding the on button with a long stick

The parallel switches makes sense to me. I'll take the contact data sheet and the electrical schematic into work today and discuss with our "electrical" guy.

Safety first,
Greg
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  #8  
Old Tue 07 August 2007, 09:11
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Greg,
I didn't see your post until just a few minutes ago. Here's how the 'latching' circuit works:

1. When the door switch is 'closed' (turned on), power is available at 4T2, which means that power is also available to the Slo-Blo fuse and the (normally closed) limit switch(es) outside the control box. The circuit continues back into the control box through the normally closed Off Switch to 5L3 (normally open) and the normally open On Switch. The other side of the On Switch is connected to A2 of the contactor's coil and to 6T3.

2. The neutral line is connected to A1 of the contactor's coil.

3. When the On Switch is momentarily depressed, the contactor's coil is energized, so that contacts 6T3 and 5L3 become a 'closed' switch contact. As soon as 6T3 and 5L3 make contact, the On Switch is bypassed, which means that you can release the On Switch without 'turning off' the contactor.

4. The contactor will stay On until any of the circuits in series with the contactor's coil is opened (i.e., limit switch, Off Switch, Door Switch).

5. When power is momentarily cut from the coil by opening any of the switches listed in step 4 above, contacts 6T3 and 5L3 open, and the contactor unlatches.
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  #9  
Old Tue 07 August 2007, 11:22
Greg J
Just call me: Greg #13
 
Hagerman, New Mexico
United States of America
Gerald and Mike,

Thanks again guys. I finally "got" it. Geeez, I'm a slow learner.

Between you two gentlemen and my "old" electrical guy at work, I understand the latching. Pretty cool actually.

I should have motors turning, maybe by the end of the week. We'll see.

Again, thanks,
Greg
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  #10  
Old Tue 07 August 2007, 11:41
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Hear that Mike? Greg thinks that we are the youngsters!
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  #11  
Old Tue 07 August 2007, 12:35
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Gray hair notwithstanding and old eyes that need a lot of magnification, this forum reminds me what it was like years and years and years ago when I was one of the 'young bucks' trying to figure it all out. Kudos to those who are joining this great adventure and are willing to jump right in.
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  #12  
Old Sat 10 November 2007, 13:49
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Can someone please help me? This weekend, I began the process of wiring up my control box but things aren't working correctly. I can't get the contactor to latch. I've checked and rechecked everything several times. I hope I'm doing something wrong but I believe the coil in the contactor is bad. Shouldn't there be an audible click when power is applied to the coil? I don't hear anything. Just now, I connected a temporary power cord directly from the wall to the coil on the contactor and checked for continuity across the terminals but there is none. However, when I manually press down on the center of the contactor, I achieve continuity.

I'm using the recommended TECO contactor.

Before someone asks, yes, there is power coming from the wall. When I press the on button, which is mounted on the control box door, the "on" light stays on until I release the on button.

Any ideas?
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  #13  
Old Sat 10 November 2007, 14:24
Tom Caudle
Just call me: Tom
 
Texas
United States of America
Doug: Take a DVM set of ac volts 200 scale and measure across the coil of the contactor. With the button not pressed you might get a few volts of AC. When you hit the button the voltage should go to your line voltage. If it does and the contactor does not pull in you have a bad contactor (not very likely). IF it the voltage does not go to full AC then something is hooked up wrong. I suspect you have both sides of the contactor coil wired to the same side of the AC circuit. Coil needs Hot and Neutral across it to activate. The pushbutton should put it across the coil to pull in the contactor then one set of contacts are used to "hold" by being in parallel with the pushbutton. It shuts off with another NC switch to break the current flow at the coil.

Another thing to try if high voltage makes you nervious: Unplug the AC cord and put an ohmmeter across the two line wires (not safety ground). Low ohms meter setting (2K). Take the lamp out of the Start button or disconnect one side of the lamp from it's connection to the AC. When you push the button the ohmmeter should register a few hundred ohms (of the AC coil). Measure across the coil with no power and get a reading. You should see close to that when you hit the button out at the two AC line cord pins.

Use your meter with one side to one leg of the AC cord (unplugged) to tack it through the circuit. Then do the other one. If you go through it methodically you will turn up the bad/wrong connection
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  #14  
Old Sat 10 November 2007, 15:59
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Doug, if you remove all wires from the contactor, then put your temp. mains wires direct to A1 & A2, you must hear a satisfactory "clunk" when you power up.

Before that you could measure the resistance across A1 & A2 to make sure the coil is present. Don't know how much it should be, but there should be something of less than 1000 Ohm for sure (I think).
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  #15  
Old Sat 10 November 2007, 16:23
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Thanks Gerald and Tom.

Gerald: I just checked the resistance across A1 and A2. There is 0 continuity until I press the button. After I sent my last email, I connected one leg of my temp power cord to A1 and the other leg to A2 and no clunk.

Tom: I'll try your suggestions in the morning when I have better light.
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  #16  
Old Sat 10 November 2007, 19:51
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Doug,
I just took a new LS Industrial Systems GMC-18 120VAC 60 Hz contactor right out of the box. With nothing connected to the contactor, I read 108 ohms across the coil. (Other brands of contactors and coils designed to work at other voltages will show different amounts of resistance.) Start with Gerald's suggestion, disconnect everything from the contactor and then connect power directly to the coil. (Be sure that you know which contact points go to the coil. Some contactors have a lot of screws and it can become really easy to confuse the coil connections with the auxiliary switch connections.) When you turn the power on, the contactor should activate. When you turn the power off, the contactor should de-activate. If the contactor's coil doesn't work properly, try another contactor.

If the coil works, then use Tom's suggestion as you rewire everything and carefully trace each connection to verify that everything is connected properly. To make things easy, print out the schematic and color each line with a red pencil as you verify connection points. That way you'll be able to tell at a glance that you've thoroughly checked each and every connection.

Just for the record, whenever I've had a problem when using commercial grade components, the problem has always been the result of a bad connection. I've never had a fresh-out-of-the-box component failure. (Obvisiously, I don't count as component failures the times that I goofed and fried things. Those were all operator errors. The sight and smell of the magic smoke let me know that I'd made a mistake.)

(Soap Box Time: One of the things that everyone is going to have to do when they build their own control boxes is to have spares of everything on hand. When you build your own box for 10% to 25% of the cost of a ready-made box, part of that price difference is the spare parts that the dealer stocks - just in case the box he sold you has a problem. When you become the manufacturer, you'll need to stock the spare parts. The good news is that even if you have a spare of everything, your cost will still be just a fraction of what if would be if you bought the controller ready-to-go.)

Above all, don't feel badly if it takes a few tries to get things working. After a while, building and troubleshooting electronics will become easier. If you want to see something really funny, just watch me attempt to do anything mechanical. You'll think that you're watching the three-stooges with me playing all three parts at the same time.

Last edited by Richards; Sat 10 November 2007 at 19:54..
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  #17  
Old Sat 10 November 2007, 20:44
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Tom, this type of thing has happened to me when I purchased a contactor with the incorrect coil voltage. If the rated coil voltage is too high, nothing happens, but there will still be a some Ohms measured. If the rated coil voltage was too low, it would clunk once, burn out and no Ohms measured after that, but the burnt smell would be there. And, for some contactor brands the coil is purchased as a seperate option - there is no coil in the case and nothing happens.
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  #18  
Old Sat 10 November 2007, 21:05
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Thanks Mike. I read and reread all of the posts dealing with the contactor and am sure I know which terminals to use so I think I'm using the right ones. However, the door switch and e-stop circuit could have had a mistake in it although I checked and rechecked it several times too. I'll perform Gerald and Tom's tests as soon as I get up in the morning. Then I'll disassemble it to see if there's a coil present and try to determine if I burned it up or something. The box discusses coil replacement but I believe the brief instructions were translated from Chinese to English by a computer so they weren't much help. At least I know it's possible to look inside it.
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  #19  
Old Sun 11 November 2007, 10:10
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Moron Obviously Needs More Supervision

Dang it. I had rather be shot than have to write this email.

The problem was my stupidity. I had the temp power cords hooked up to the NO relay terminals. I hadn't even noticed the coil connections on the back of the contactor. When I disassembled it and started trying to figure out how it works, the coil connections were staring me in the face. Heavy sigh. I apologize for wasting everyone's time but maybe some other dummy like me can learn from my stupidity.

Gerald, we need to add a smiley face with egg on it.
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  #20  
Old Sun 11 November 2007, 10:17
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Doug,
We've all been there and done that. It's part of the price that we all pay to get an education in electronics.
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  #21  
Old Sun 11 November 2007, 10:45
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Doug, we have all been there and done that.

Close up photos of that relay will help the next generation. . . . (please )

Even those that havn't wired their Teco's yet can give us photos - don't leave it all to Doug.
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  #22  
Old Sun 11 November 2007, 13:21
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Not wasting my time here in florida....your just helping me not make any mistakes!
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  #23  
Old Sun 11 November 2007, 18:23
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
Thanks guys. Attached is a photo. I've circled the terminals in red. Notice that they are are low on the back and that's why I overlooked them.
Attached Images
File Type: jpg Teco Contactor.jpg (30.9 KB, 980 views)
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  #24  
Old Sun 11 November 2007, 22:33
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Thanks Doug!

Rather impressive that your wiring doesn't show any exposed copper - just be sure you don't have any pinched insulation either.
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  #25  
Old Mon 12 November 2007, 03:28
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Question for Gerald or Richard or anyone that can explain this to me.

First let me explain that I am getting an education here with regards to the electrical and electronics. I have some knowledge so I am asking questions that I am not finding on my own.

I am also assuming that the CN-22-F6 is one correct choice for the contactor.

If you look at the TECO CN-22-F6 contactor specs from FactoryMation, you find that the Rated Power Capacity at 120V is 2HP/24A and 240V is 5HP/28A. The PorterCable 7518 router is a 3 1/4 HP at 120V / 15A. I am thinking of running my MechMate at 120V.

My question is : Doesn't the contactor need to have a higher HP capacity if the tool, in this case the router, is of a higher HP?

How does it affect the fact that you might have a dust collector also running off of the same contactor?

If not briefly why?

Point in the direction of a thread if there is one.

Thanks
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  #26  
Old Mon 12 November 2007, 04:14
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Hi Nils, welcome!

You have to believe us when we tell you that Porter Cable is lying
You have just seen another proof of it yourself - a 15 Amp tool cannot give a genuine 3 1/4HP power. We tend to believe Porter Cable on the 15 Amps as an absolute max, so the contactor is sized on the amp rating only.

You must know how many amps your dust collector, or any other accessory might draw, your contactor must be able to handle the sum total of all the amps plus a bit spare.

These things are not absolute. Overloading the contactor will shorten its life. Oversizing it will lengthen its life. But this does nothing for its level of performance. An undersized contactor will start & run stuff as well as an oversized contactor, only for a shorter time.
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  #27  
Old Mon 12 November 2007, 04:30
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
(PS. I have not checked the CN-22-F6 number as being the correct one.)
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  #28  
Old Mon 12 November 2007, 07:18
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Gerald,

Thanks for the quick reply.

I will believe you about the Router HP. It appears that the number of the Amps is what is important when it comes to sizing. So if the Router needs 15A and if the dust collection needs 15A then you need a 30+A. The + is for the spare.

One answer brings on additional questions.

Looking at the spec sheet that FactoryMation provides (hopefully a copy is attached), on the second page there are three Rated Power Capacities blocks. One is for IEC, CNS and UL. I get the UL as it relates to HP. But what does the IEC and CNS stand for?

2nd Question:

If you have a contactor in your system and later you add additonal pieces of equipment, can you add another contactor or is it better to replace the current one with a higher rated one if you need more capacity?

Thanks for your help and your machine.

Nils
Attached Files
File Type: pdf CN-18toCN-22.pdf (182.6 KB, 174 views)
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  #29  
Old Mon 12 November 2007, 07:25
Doug_Ford
Just call me: Doug #3
 
Conway (Arkansas)
United States of America
That may not be the correct part. Factorymation substituted due to a shortage. I can't remember if it was the contactor or the disconnect. In any event, I remember that the part they substituted had a higher capacity.

I tried hard to follow the rules you gave us in the "wiring quality" thread. To check whether insulation was pinched, I touched DVM probes to the terminal screws at both ends of the wire I was installing to check for continuity. That's easy to do in the control box but a little tougher when I started installing the cables on the table.
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  #30  
Old Mon 12 November 2007, 07:45
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Nils,
Good morning!
It's good to see you up on the forum. It's a great point you bring up about the router and other accessories. You and I didn't spend much time at the shop the other day, but if you look at the main switch and contactors I have in my box you will see I have set it up for 22A/pole and a main switch with 40A/pole all at 110V. (This allows for the 17.6A useful load [22A x .8 factor = 17.6A] ) Hopefully, by next week I will have something to show you in person. (Nil's lives here in Orlando and has hopped on the MM wagon!)
Sean
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