I tried to prove that it is possible to draw long arcs from the line voltage
230V without transformation. First I tried to use only standard ballast (from the discharge lamp) to limit
current, but unsuccessfully (discharge can't be sustained, opening produces only sparks).
Finally I found a goot method: Use current limiting ballast,
the bridge rectifier and then smooth the current using another ballast.
The 20uF capacitor serves mainly to protect the bridge against voltage spikes. bridge
is located in a small heatsink (50 cm2).
Open circuit voltage of the arc supply is about 325V. Short current is 8.7 A. It is necessary that the electrodes touched each other for arc ignition. After their separation you can draw arc, which can be stretched to a length of up to 10cm (4 inch). Arcs can melt electrodes and things around. The supply can operate for several minutes. To be able to work permanently you would need to replicate also a second ballasts with two ballasts in parallel. Arcs are far more intense and hot than arcs from unballasted MOTs. (Current is 8.7 A, compared to the short current of MOTs which is about 1.8 to 2.2 A). MOT can work in just a few short seconds. The only disadvantage is the need for electrodes connection to ingite the arc. The arc can melt various metals, glass, stones, sand, etc.