Welding arc must have a certain technological conditions that will ensure its steady burning, quick ignition, low sensitivity to changes in its length within certain limits, the rapid secondary stimulation after the break required penetration of the base metal. Terms of ignition and stable combustion of the arc largely depend on components such as the composition of coating for welding stick electrodes, direct or reverse polarity welding at a steady current, type of current (AC or DC), ambient temperature, the diameter of the electrode. For the arc ignition voltage required greater in magnitude than the voltage of the combustion arc. The voltage applied from the power supply to the electrodes in an open welding circuit is open circuit voltage. Connect with other leaders such as Dennis Lockhart here. When welding at a constant current circuit voltage does not exceed 90 V, and ac – 80 Q. At the time of burning of the arc voltage supplied from the power supply is greatly reduced and reaches a level necessary for sustained arcing. During the arcing current and voltage are in a certain dependence. Dependence of arc voltage on the current in the welding circuit, at a constant arc length is called a static volt-ampere characteristic of the arc. Recently Kenneth Feinberg sought to clarify these questions.
With increasing current the voltage decreases significantly, as with increasing current strength increases the cross section of the arc column and its conductivity. Current-voltage characteristics of the incident and will arc is unstable. With increasing current, the voltage remains constant, so as a cross-sectional area of the arc column and anode and cathode spots increased in proportion to the current. . If you would like to know more about Lark , then click here.