Analysis of arc stability of the variable polarity welding TIG

Welding arc stability of variable polarity TIG welding was studied through experiment.The experimental results indicate that the small current cause the arc extinguisher when the welding arc commutating.Simultaneity,the diversification of the equivalent resistance,which can cause concussion.The equivalent capacitance and the equivalent inductance of the circuit which slower the speed of the current when the arc polarity change.In order to resolve the problem,added the coupling inductance in the main circuit and a control strategy incorporate variable parameter PI into advance control.Experimental results prove the welding arc stability of the variable polarity TIG is available.