Murex Tradesmig 201 tripping out mains RCB

[eddie49]

Is there anything I could put on the threads to help prevent arcing?

Nothing that I know of that would withstand the heat. If you have any, mica sheet ( e.g. from the heating element of an iron ) inserted between the coils would work. Otherwise, if there is space to the rear of the current layout, I would spread the coils so that the shape is more of a "U" rather than the existing "C".
Not much point in getting a new one, it will have the same issue after you fit it.

Fixing this resistor issue will hopefully prevent the arcing seen inside the welder. It may or may not solve the breaker tripping.

 

[Tim H]

Nothing that I know of that would withstand the heat. If you have any, mica sheet ( e.g. from the heating element of an iron ) inserted between the coils would work. Otherwise, if there is space to the rear of the current layout, I would spread the coils so that the shape is more of a "U" rather than the existing "C".
Not much point in getting a new one, it will have the same issue after you fit it.

Fixing this resistor issue will hopefully prevent the arcing seen inside the welder. It may or may not solve the breaker tripping.

I have just stretched it and it looks a lot better. I have had to cable tie one of the cables that came from the 3 big capacitors to the chassis just in case it moved too close. I presume that coil will get hot? There is damage on the lance connection to the machine. There has been arcing on the threads. The lance was tight but could be that causing the trip? Guess if it arcs to the chassis it will go to earth? I will replace the lance and socket, but is there a grease or compound I could put on the threads to help prevent this re-occurring?

 

[eddie49]

Yes, the coiled wire resistor will get hot, so any plastic parts or insulated wires should be held clear.
The threaded brass Euro socket, the entire wirefeed assembly, and the MIG wire spool will all be "live" with the welding voltage ( +15 to +30 v DC ). However, the negative of this supply is the work return cable and clamp ( "earth" clamp ), not the AC mains earth. The primary/secondary separation of the main transformer provides isolation, so there can be no arcing from the Euro socket to the machine chassis ( and there should be a large gap and a full plastic shroud around the socket anyway ). I have sometimes had a Eurotorch plug not seating properly, but jiggling the plug whilst turning the locking collar has fixed it.