Testing out tig, no arc

  1. seileren New Member

    Messages:
    13
    Location:
    Norway
    Hi

    I've never done any welding before and just aquired an old kemppi ekatig 160HF (3phase transformer, DC). It has stick mode and TIG with HF. Stick mode seems to work fine, but in TIG mode I get little action. Zero response trying scratch start, but when pushing/holding in the HF button on the torch I get sparks but are not able to strike an arc. I did not connect Argon gas for the test, thought I should be able to atleast get a little arc going without?

    I successfully tested continuity between DCEN, the gas connector for the torch, and the tungsten tip. Measuring voltage between DCEN and DCEP on the machine i get 0v in TIG mode, is this correct? When holding in the HF button I get voltage. If I've read correctly you just push/hold the HF to get an arc going, not needing to hold it in while welding?

    From the manual:
    The TIG high-frequency unit accommodates the ignition of the TIG arc without touching. The high frequency unit also has a controller for the contactor and time control for gas post flow.

    welding current values: idle voltage = 98V. (I guess this should be same for stick and tig mode?)


    Thanks for any help/reply!
     
    Last edited: Feb 17, 2018
  2. Paul.

    Paul. Moderator Staff Member

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    When you say HF button do you mean the torch switch?, you need to keep that pressed, the hf will initiate the arc then switch itself off when the machine senses that the arc is established, keep it pressed while welding then release button to stop welding.
     
  3. seileren New Member

    Messages:
    13
    Location:
    Norway
    Paul: Yep! Sorry I'm not that much into the terminology yet. Should there be any idle voltage when its not pressed? I see manual says idle voltage=98V, but it doesnt say in which mode (I assume both). I guess this means I should measure ~98V between DCEN and DCEP when its powered on and don't have the torch switch pressed? I get 0V in TIG mode.

    I guess what I am wondering is if only the HF circuit could be working and not the welding circuit? While trying to scratch an arc while keeping the torch switch pressed (still no gas connected) I ended up burning a hole in the 1.5mm plate, would this be possible if there was no arc involved or welding circuit wasn't working?
     
  4. MattH

    MattH Member

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    3,578
    Location:
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    If you are burning through the plate then you have welding current.

    To maintain an arc you are going to need gas.

    Tungsten Inert Gas.

    At the moment you just have T.
     
    Richard. likes this.
  5. Paul.

    Paul. Moderator Staff Member

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    I would say your machine is working ok, you just need some argon as Matt says,
     
  6. Richard.

    Richard. Member

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    Striking up is extremely poor with out argon flow.
    To the point on some machines it simply won’t strike without gas. Argon carries hf to the job. A lot of people do Machine tests with out argon thinking it’s just a test then often the machine doesn’t strike and the belief is it’s faulty. Connect the gas then test it. As you’ve got hf and OCV when the switch is pressed I see no reason why that wouldn’t work. Connect the gas then try it.
     
  7. seileren New Member

    Messages:
    13
    Location:
    Norway
    Thanks for your replies! Got a little bit scared with the 0V measurement between the DCEN and DCEP, and no spark / sign of life when trying scratch start. I'll try again with gas tomorrow, didn't have time today. Guess I need to do some tip grinding as well hehe..
     
  8. Richard.

    Richard. Member

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    18,091
    Location:
    Cambridgeshire
    In stick mode you’ll have open circuit voltage between the terminals. This will always be there in stick. 98v is a very healthy ocv.
    In tig mode you’ll have 0v across the terminals. You press the switch and you’ll get voltage. Hold the trigger to maintain the arc. Release it and it stops.
    Little tip from experience ..... if your testing for ocv in tig mode turn the hf off.
    Take it from me high frequency voltage can very quickly knacker your multi meter.
     
  9. Paul.

    Paul. Moderator Staff Member

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    Location:
    Northampton. UK
  10. seileren New Member

    Messages:
    13
    Location:
    Norway
    So today with the argon flowing (dont have flow meter yet) I was able to get an arc and a puddle going, atleast for some seconds. The hf gives me that little spark but I still had to touch metal with the tungsten to get the arc going. There is also just about 6cm left of the tungsten so not really much to work/train with. I guess the rest now is up to the user and some practice :)

    Regarding the hf I've read you shouldn't use it on cars with electronics or around computers. Does this mean you shouldn't use it near a compute like 3feet away, or just that you shouldn't have it connected to the metal you are working on?

    Again thanks for the help and feedback last night, much appreciated!

    (And yeah, my meter is still working:))
     
  11. AndersK Member

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    617
    Location:
    Sweden
  12. seileren New Member

    Messages:
    13
    Location:
    Norway
    AndersK: nice, grabbed the pdfs :) Do you think I would still get a steady spark if the spark transformer wasn't working? The spark I get between the metal an the tungsten looks pretty good to me, but then again this is my first time trying out tig.. I'll check out the connections around it, get a new tungsten and some scrap metal and try again.

    The ekatig had been collecting dust for about a decade in an old garage before I got it and the prev owner knew very little about it.. Funny thing is the connections to the hf torch switch were cut of from the socket inside the chassis, had to solder them back on..
     
  13. AndersK Member

    Messages:
    617
    Location:
    Sweden
    No, no spark if it's broken. If it's been sitting for long I would loose all bolted connections and give them a scrub with scotch Brite and reconnect. Checking with an ohm meter can mislead. A bad connection can show low resistance but cannot carry over the high current. Been there before.
     
  14. seileren New Member

    Messages:
    13
    Location:
    Norway
    Some more progress today. Stopped by a local welding garage and got a new tungsten, gas lens, collet +body, some rods and scrap metal.
    Cleaned and retightened a bunch of connections and went over with some crc electronic cleaner.

    After this I had no issues maintaining an arc, but still had to touch the work piece with the tungsten to establish it, even tho the hf spark seems good and stable.. I took a little pic of the hf unit:

     
    Last edited: Feb 19, 2018
  15. MattH

    MattH Member

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    3,578
    Location:
    Bristol
    That’s not the HF unit, the unit will habe a wire leading from it to the torch connection with a lot of insulation and usually an extra cover on it to prevent leakage (HF is also high voltage and by design can jump air gaps).
    If the unit is a spark gap generator then it might need the gap adjusting (search Youtube).
     
  16. MattH

    MattH Member

    Messages:
    3,578
    Location:
    Bristol
    Take a pic of the other side of the unit (black box).
     
  17. seileren New Member

    Messages:
    13
    Location:
    Norway
    Right! Bad naming from my end, manual says "pulse unit".. I was focusing on the possibility of leaking capacitors. Will get a better pic of the other side tomorrow, the one I took today was out of focus. Also not sure if its spark gap generator, but would sure be nice if some adjustment would fix it :)
     
  18. Jlg

    Jlg Member

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    Location:
    Cumbria
    I may be asking you a stupid question but have you got the torch connected properly
     
  19. seileren New Member

    Messages:
    13
    Location:
    Norway
    Jlg: everything is worth checking, especially with a beginner like me. Funny how easy everything looks on youtube jus to later figure out you missed some stuff or the creator leaves those small things out that everyone with experience just takes for granted. Regarding the torch I've connected the gas connector good (tho not with a wrench) and the clamp twisted tight in place. HF switch connector plugged in and locked.
     
    Jlg likes this.
  20. Jlg

    Jlg Member

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    2,092
    Location:
    Cumbria
    image.png Have you got gas conected to one and power conected to one of the dins connectors because that's where you're going wrong from what I can see on the Internet it's a gas and power connection in one like in the picture I found of a kempi the same as yours so where you gas is connected is also the power for the tig side and the spare dinse is for mma hope this helps you
     
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