in welding set how the current increase?

Answer 1

you increase the amperage for thicker welds and decrease amperage for lighter welds. this is true regardless of whether youy use a/c or d/c welder. thick materials use a hiugher amp setting than say light tubing. too little current, the weld won't hold, to much and you can blow hole through the metal. a good weld is done with a fast rod but should be specific for certain metals, and for a/c or d/c welding. wire welding is similar but gas wire, no flux, and flux wire machines make a big difference in how easy the welding is. a/c welding arcs jumps all over the place and only experienced welders can do it well. d/c and wire are both very easy since you get the arc right off and it is easily controlled.

Answer 2

no.. actually , the voltage/potential difference is increased between the 2 surfaces to be welded by the help of a high capacity transformer,creating such a high p.d. makes electrons jump throught the air to the positively charged metal from the negatively charged one, creating lots of heat, and molten metal..