Welding a welder

[GraemeVW]

Odd question maybe, but my eland is a little too long and a bit too high to fit under my bench with the gas bottle on the back.
I only use 20l bottles, so not even big ones.

I was thinking of moving the rear wheels forward, cutting the back bottle support off, and making a new, shorter, lower bottle support so it will all wheel under the bench.

Thing is, this will be my only working welder.
Will it throw a fit if I use it to weld itself?
It may be no different to normal work, but the welding circuit earth looks separate to the other earths so wasn't sure.
I will trace the earths, see if its all linked back to the chassis earth or not, just don't want to fry anything!

Otherwise I guess I'll have to fix the clarke welder too and use that on the eland chassis. Whole point of buying the eland was so I didn't have to fix the clarke though!

 

[eddie49]

Both the positive ( = torch ) and the negative ( = "the Earth lead" - actually the workpiece return cable & clamp ) connections of a MIG's DC output are floating. There is ( should be! ) no connection to the casing/chassis/metalwork of the machine, nor to AC mains earth.

Putting the return clamp onto a piece of metal that happens to be the chassis of a welder and is connected to AC ground should be no different than, for example, welding on an RSJ that is embedded 6 feet into the ground.

However, it wouldn't hurt to do a quick Ohms check on the Eland, making sure that the chassis does go to the Earth pin in the 13A plug, and doesn't go the work clamp nor to the MIG torch tip....

 

[GraemeVW]

Both the positive ( = torch ) and the negative ( = "the Earth lead" - actually the workpiece return cable & clamp ) connections of a MIG's DC output are floating. There is ( should be! ) no connection to the casing/chassis/metalwork of the machine, nor to AC mains earth.

Putting the return clamp onto a piece of metal that happens to be the chassis of a welder and is connected to AC ground should be no different than, for example, welding on an RSJ that is embedded 6 feet into the ground.

However, it wouldn't hurt to do a quick Ohms check on the Eland, making sure that the chassis does go to the Earth pin in the 13A plug, and doesn't go the work clamp nor to the MIG torch tip....

The mains earth is direct to the chassis star point, along with all the other small earths.
The DC earth is direct to the small transformer.

 

[eddie49]

The mains earth is direct to the chassis star point, along with all the other small earths.
The DC earth is direct to the small transformer.

That sounds correct. The small transformer is the inductor or choke, which has just one winding of thick solid wire. It slows the rate of the initial current spike when the MIG wire short-circuits onto the work.