Welder tripping

  1. Liam Mepham New Member

    Messages:
    17
    Location:
    Uk - south east
    Hello all,

    not your usual tripping post here.

    so yesterday doing some welding with my trusty cheap and basic Clarke 90en on some van sills - nothing major.

    overnight welder was stored in shed out the weather.

    Today get it out setup and it instantly trips the 20amp rcbo breaker its on, but only when connected to the van.

    I believe it’s not the breaker because it will weld fine if I just weld two bolts together.

    here is a video
    https://sitecore.box.com/s/dr3hf1pk3la9lcf4qkn84d3kvx2ajgfl

    Obviously it somehow finds ground and trips out...

    any tips or tests I can try to work out what’s going on welcomed, racking my brains now!
     
  2. voipio Member

    Messages:
    877
    Cambridge, UK
    Does connecting an Earth cable directly to the van (i.e. welder not connected to the mains) cause the same problem? The video doesn't load here, unfortunately!
     
  3. jimbo84 Forum Supporter

    Messages:
    1,123
    Location:
    Up North
    The trouble with RCBOs is you don't know whether they're tripping due to overload or earth leakage. I'd be very surprised if it was finding a fault to earth through the van as it's sat on rubber tyres so insulated from earth, unless you have it jacked up of course.

    Are you using an extension cable to weld to the van and not when welding the bolts? Does it trip the RCBO when you first turn on or strike up or does it let you run a bit of a bead and then trip? Is the van jacked up?
     
  4. Liam Mepham New Member

    Messages:
    17
    Location:
    Uk - south east
    Sorry I should have said only when I touch the trigger to start welding will it trip if the negative lead is connected to the van, or any metal touching ground.

    the video shows me welding two bolts together on a block of wood, then taking them two bolts and placing them on the ramps the van is sat on, as soon as I touch the trigger it trips.

    does that link not work? Let me try again
     
  5. Liam Mepham New Member

    Messages:
    17
    Location:
    Uk - south east
    All tyres are on, that’s why it’s so confusing.

    both the bolts and when attached to the van welding was done on extension cable, exactly the same as yesterday...was welding for a few hours with the exact same setup, only difference today is the weather...
     
  6. jimbo84 Forum Supporter

    Messages:
    1,123
    Location:
    Up North
    Is any metal part of the van touching the ground either directly or indirectly through an axle stand or is it sat on tyres on the ramp you mentioned?
     
  7. Liam Mepham New Member

    Messages:
    17
    Location:
    Uk - south east
    Just tyres, back tyres are on metal ramps.
    No axle stands or any other part of the van touching the floor
     
  8. jimbo84 Forum Supporter

    Messages:
    1,123
    Location:
    Up North
    Ok so in that case you haven't got an earth fault unless it's finding a path inside the welder itself, if only the rubber of the tyres is touching the floor it can't be finding a path to earth unless you're welding at 10,000v.

    It's looking most likely like an overcurrent fault, most likely inrush current. Is there anything else plugged into that circuit, particularly something that wasn't on yesterday?

    When I first used my oil filled welder from the garage supply it worked ok. The next time I used it it would trip the breaker on turning it on, it was a 16a B type MCB. Nothing I could do after that day would let me turn the welder on without the MCB tripping even though it worked fine previously, same with a big motor I had. I swapped it out for a type C and all was well.

    Smaller MCBs don't ride out start up currents well, particularly if they're on long cable runs/extensions. 32a handle it better but anything smaller than that can trip due to start up currents.

    Do you have a socket circuit on a larger RCBO you can try it on?

    Is the welding clamp definitely making a good connection to the body?
     
  9. a111r Member

    Messages:
    424
    Location:
    London
    The choke connection to the transformer on those machines is prone to go high resistance.
     
  10. Liam Mepham New Member

    Messages:
    17
    Location:
    Uk - south east
    Nothing else plugged in.

    I could try of an external socket running on a 32amp rcbo for the ring...but that would mean increased extension lead length. I’ll try that tomorrow morning.

    I think the moister makes the welder internal resistance higher and then the inrush current is off the charts.
    Happened before, next sunny day absolutely fine!

    trouble is it will trip even when not connected to the van I.e it will well bolts fine on a block of wood, move them bolts onto the ramp the van is sitting on and it trips...wtf. So the clamp is making a good connection to start with...move it to the ramps and the connection is exactly the same but it shorts you ground?
     
  11. Liam Mepham New Member

    Messages:
    17
    Location:
    Uk - south east
    Is it worth replacing them? Can you even get replacements?
     
  12. a111r Member

    Messages:
    424
    Location:
    London
    It's an alloy crimp joint that's possibly at fault. If corroded or burned, chop it out and use a large screw terminal block to remake the joint.
    Have a look in the Clarke section.
     
  13. Liam Mepham New Member

    Messages:
    17
    Location:
    Uk - south east
    https://www.mig-welding.co.uk/forum/threads/another-deal-clarke-im-perplexed.100987/

    thanks found it! Looks like you’ve done quiet a bit with these welders, thanks for the help.

    I will go have a look at the connection in a moment and report back, it’s a nice sunny day here today so I bet it just works as normal...stay tuned.
     
    a111r likes this.
  14. a111r Member

    Messages:
    424
    Location:
    London
    Whilst the case is off, clean up the three rocker switch spades, they're another common one..
     
  15. Liam Mepham New Member

    Messages:
    17
    Location:
    Uk - south east
    ok will do.

    found the choke connection, added a bit of solder which made it look a bit nearer and a better connection..no difference.

    will do spade connectors too now.
    Is there a way to check voltages inside to check the components?
     
  16. a111r Member

    Messages:
    424
    Location:
    London
    You can check the four open circuit voltages from the outside, measuring the DC between torch tip and the earth when triggered. Range is approx. 18v to 28v on these.
     
  17. Liam Mepham New Member

    Messages:
    17
    Location:
    Uk - south east
    The voltages check out as follows
    28.6 max 2
    25.8 max 1
    21.8 min 2
    20.1 min 1

    so they seem in range hmmmm
     
  18. Liam Mepham New Member

    Messages:
    17
    Location:
    Uk - south east
    Spade connectors all cleaned up too
     
  19. Liam Mepham New Member

    Messages:
    17
    Location:
    Uk - south east
    Tried on the 32amp rcbo socket ring circuit with an extension lead, still blew it
     
  20. a111r Member

    Messages:
    424
    Location:
    London
    Most odd...
    Gas shroud OK, free of build up?
     
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