Relay clicks but wire doesn't feed

tollertoller · May 20, 2016

Amazing.

Mike, I did as you suggested and pushed in the contactor high output relay and when I pulled the trigger on the gun, the wire feed activated and produced an arc.

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The PCB connects to the computer via the 6 pin junction and the 4 wires, 2 are out and 2 are in. What is it I'm looking for next?

This is an incredible forum!

mike 109444 · May 20, 2016

There could be a couple of reasons for it not to operate correctly. If the "operate" feed to the contactor (not computer :whistle:

auto correct ? :doh:

) is missing then there is a fault on the pcb or wires from pcb to contactor. Other reason is that the contactor is faulty. If you look at the contactor (which is just a big a55 relay) you will see there are several thick wires. These are the high current (and maybe high voltage) that the contactor has to switch on and off. There will also be a pair of thinner wires (think they are white on yours, pic not to clear), these are connect to a coil inside the contactor that when energized pulls the contactor in (on) and does what you did by pressing the button! If you put a meter on each of the two coil (white?) wires where they connect to the contactor and set your meter to AC volts, you should see on your meter a reading when you pull the trigger may be 12, 24, 48 110 or 220 AC depending what it is fed from. If you get none of these reading then try meter on DC but it is unlikely that it is a DC operated one as they are a bit more expensive as there is more copper in the coil !
If you get a reading of AC voltage then it's very likely your contactor is duff (well the coil is) Contactors are available and there should be a number on it that should allow matching up a replacement.
If you don't get a voltage reading at the contactor when trigger pulled then follow the two thin (white?) wires back to the pcb, checking there condition as you go. You could also do a resistance reading from one end of the wires to the other just to check for breaks. If ok then post up where they connect on the pcb and will try and figure what next but would need a pic of under side of pcb (track side)

tollertoller · May 21, 2016

I do believe here lies the problem. There is 122 volts AC at the two white leads and the same for the 2 brown leads.

Is the CNA-2 a separate item from the CN-16? Do I buy they separately and put them together or should they come as a pair?
I haven't attempted to pull them apart in case they are tricky to assemble.

mike 109444 · May 21, 2016

They are modular to a certain extent (I think) but believe that they are put together in the factory so they may have a range of say CN-16's that can then have a CNA2 or CNA4, CNA6 etc (just guessing at the range numbers!). So when the maker of the welder needed a contactor they would have chosen a CN-16 and CNA2 from a list to match the operating voltage and switching voltage available and also how many cables they needed to switch ON and or OFF ( if you notice on yours some connections are marked NO = Normally open and some marked NC = normally closed, so in there relaxed (no "operate" power applied) some will be open and some closed.
I have a quick Google of TAIAN and there is a company under that name linky http://www.taianjaya.com/p-CU-CN-Series-IEC-Contactors-16.html They may no longer do that particular contactor as it has been superseded but they will do an equivalent. It may be possible to get just the coil (not this one I don't believe is suitable as it's for 480v and would probable not operate on 120v unless yours is same ?) http://www.ebay.co.uk/itm/Replaceme...419162?hash=item2335db4a1a:g:EfoAAMXQlgtS89uB
In the UK there are companies that supply to the electrical trade these types of contactor as they are used for switching in plant rooms for say boilers etc, don't know what you have in USA.
IF you remove it to take along to such a place MAKE SURE YOU LABEL ALL THE WIRES AND TAKE LOTS OF PHOTOS WITH LABELS ATTACHED. You should be able to leave the jumpers in place when/if you remove it and if you can find the right sort of supplier they should be able to cross reference it with a suitable replacement. Might be worth doing a local (to you) google for "Taian contactor suppliers" and that way you will find a better match. Remember this is only a BIG switch at the en of the day !

tollertoller · May 21, 2016

That coil is similar but not the correct voltage. Mine says 220/240.
I have removed the bits leaving on the jumpers and marking the wires as well as lots of photos.
So is the big coil the most likely culprit and not the CNA2 smaller unit. A matter of one thing at a time so we'll see how I'm able to source the parts or if I need an alternate combination replacing the CN-16 with another part.

Thank you again for the guidance.

tollertoller · May 21, 2016

Believe I've found the coil.
http://www.ebay.com/itm/Teco-Replac...hash=item2a4e8e5a27:m:m0VzpYUe8sQ63w4OIUaFBVQ

mike 109444 · May 21, 2016

I had expected it to be a 120V one !
Still it was working so should be ok.
If you set your meter to Ohms and meter across the two terminals of the coil you should find it's open circuit, confirming it is duff.

Robotstar5 · May 21, 2016

CN16 is a contactor and CNA2 is an add-on or auxiliary contact block, you should be able to slide the add-on block off while depressing the retaining clip under it.

You state you have 122VAC on the 2 white wires which appear to be the coil connections?, yet your coil is marked 220/240VAC, the coil will not operate correctly on half voltage.

tollertoller · May 21, 2016

Robotstar5 said:
CN16 is a contactor and CNA2 is an add-on or auxiliary contact block, you should be able to slide the add-on block off while depressing the retaining clip under it.

You state you have 122VAC on the 2 white wires which appear to be the coil connections?, yet your coil is marked 220/240VAC, the coil will not operate correctly on half voltage.

Do you mean that based on the voltage via the two white leads being 120 and the voltage from the two browns being 120 that it wouldn't operate because it calls for 240? If the brown wires are one leg and the white ones the other leg, then together wouldn't that be 240?

tollertoller · May 21, 2016

mike 109444 said:
I had expected it to be a 120V one !
Still it was working so should be ok.
If you set your meter to Ohms and meter across the two terminals of the coil you should find it's open circuit, confirming it is duff.

When I checked the coil leads for continuity, it was incontinent (no continuity; just trying to be clever). Set to ohms, the reading was .514; I don't know how to interpret that number. Is this coil good or toast? Or am I using my voltmeter wrong? I'm capable of most any mistake.

Robotstar5 · May 21, 2016

tollertoller said:
Do you mean that based on the voltage via the two white leads being 120 and the voltage from the two browns being 120 that it wouldn't operate because it calls for 240? If the brown wires are one leg and the white ones the other leg, then together wouldn't that be 240?

The coil connections are normally marked A1 & A2 and it looked like you have a white wire going to each, I couldn't see any brown wires near the coil connections.

mike 109444 · May 22, 2016

As I was unsure what might be a typical reading for such a coil I did a google of "resistance value of a 240v ac contactor coil" and the results seam to imply that on a 120vAC coil you would see a resistance of about 100 to 200, ish ohms and for a 240vAC coil it would be 400 to 600, ish ohms (not figures rounded to give aprox values)
See the reply post 3 here http://cr4.globalspec.com/thread/63786/Contactor-Coil-Resistance-Values
and the top one of the list here (AC coil data for CA7 etc..) http://www.sprecherschuh.com/library/techdocs/posts/2014/01/ca7-coil-resistance.html
Assuming I am taking your meter reading as 514 Ohms (.514) that would fall within the values for a 240/220 coil indicating the coil is good! BUT the operating voltage going to it is wrong.
As I believe in the states you can have domestic supplies that are 120V + 120v (two phases ?) then most items operate from one phase to neutral BUT for heavy current devices (big washing machines and there heating elements ?) you have the facility to run phase to phase giving you 220v. I am not 100% on this as I have only once needed to get a large bit of kit (wired for USA 220v 60Hz phase to phase) to run on UK 240 50Hz via a very big ups set to 60Hz and two big transformers, did not go well !
Other mentions of the 220v supply in USA have been from queries on this forum form from members in USA asking if they should up grade there small welder (120v) to a 220v machine and also some of the USA "home make over show!" where they talk of the utility room needing a bigger supply for wash machines etc.
So my question would be what does the rating plate on the back of the welder say ? As I wonder if you have been running this machine from a 120v supply (and it has just about been working) but now is struggling to pull the contactor in and should be on a 220v supply?

tollertoller · May 23, 2016

It is and always has been running on 220v. If you look at the photo of the CN-16 above with the two white leads, you can see one of the two brown leads going to the rear. The other brown lead comes in from the rear. As I look at this, I realize that the coil sounds like it should be 120 as RobotStar pointed out.

Robotstar5 said:
The coil connections are normally marked A1 & A2 and it looked like you have a white wire going to each, I couldn't see any brown wires near the coil connections.

You are absolutely right. There are only two white leads to the coil. My thinking is off.

tollertoller · May 23, 2016

Let us assume that the bits are correct as it functioned and the markings are right. I should have gotten 240 volts between the two white leads and instead got 120. Each of those leads should have been 120 and together made 240.

LECKYBELL · May 23, 2016

Do the two white leads go back to the pcb and to the out terminals? If so you should be getting the correct supply 240 VAC going into the card on the in terminals, I think you have a supply problem to the card as I have not heard you say that L1 comes on when the relay is energised, I think L1 monitors the output of the relay on the card feeding the coil on the contactor. Thats my two penworth for what its worth

mike 109444 · May 23, 2016

tollertoller said:
Let us assume that the bits are correct as it functioned and the markings are right. I should have gotten 240 volts between the two white leads and instead got 120. Each of those leads should have been 120 and together made 240.

I am a bit unsure what/where you are metering. If the two ends of the coil where the screw wire clamps are, as in the last pic of your post number 25 is where you are metering then yes you should see 220vAC I assume one white wire is clamped under each screw clamp. When you say "each should have been 120 were you metering between one of the whites and the machine frame ?? which would not be the way to meter it.
Much as Leckybell has said the 220V goes onto the pcb, then is turned on and off (possible by the relay on the pcb). So you would need to confirm that there is 220v going on/into the pcb. Maybe post a pic of pcb rear would allow tracing across pcb.

LECKYBELL · May 23, 2016

It might be 415vac going in as there is a large wire wound resistor on the board next to the relay so be careful

mike 109444 · May 23, 2016

LECKYBELL said:
It might be 415vac going in as there is a large wire wound resistor on the board next to the relay so be careful

Should not be 415 as this is a domestic welder rather than industrial.

LECKYBELL · May 23, 2016

Your right Mike, my mistake, but it would still be nice to see the reverse of the board

tollertoller · May 25, 2016

I find myself a bit lost so have taken a bunch of photos that perhaps can help with the diagnostics.

As best as I recall, when I pushed in CNA-2 manually and fired up the torch and the wire fed and created an arc, at that point I believe all 4 of the red lights were bright.