Abstract: The invention relates to a welding method and apparatus. According to the method between the welding wire and the base material an arc (4) is electrically formed, which behaves periodically (12, t2) in such a way that the duration of the period is (t2) and within the period (12) at least on average short-circuit periods (11) arise, which have an average duration (t1), and the arc voltage is controlled. According to the invention, the arc voltage is controlled at least mainly in such a way that the ratio of the average duration (t1) of the short-circuit periods (11) to the period duration (t2) is kept to a desired magnitude.

Abstract: The present invention concerns a half-bridge inverter and a method for controlling such a welding inverter which has a nominal output power P.sub.n and a nominal operating angular frequency .omega..sub.t, the inverter being comprised of a DC power source (E); of a capacitor configuration comprising at least one capacitor (C.sub.n), the circuit being connected at its first end to one end of the DC power source (E) and at its other end to a point A; of two switching elements (T.sub.1, T.sub.2) connected in series over the DC power supply (E), the switching elements being capable of controlling the pulse width .tau. of the current to the welding load, and thus the power to the welding load, whereby .tau..sub.max determines the nominal power output of the inverter; and of a transformer primary (L.sub.p) connected at its first end to point A and at its second end to the center point of the switching elements (T.sub.1, T.sub.2), and the current switched through the primary has a peak value I.sub.i.

Abstract: The present invention relates to a method for measuring the free wire length in hot-arc or short-arc MIG/MAG welding by making use of the typical behavior of the current or the voltage in the bead short-circuit situation, in which the voltage rises in different ways depending on the free wire length. The phenomenon can be used for measuring the free wire length.

Abstract: An improved D-C to A-C inverter circuit is provided including push-pull sequentially activated thyristor switches connected across a center-tapped D-C voltage source with a saturable reactor connected in series between each thyristor and the center-tap return branch and at least one saturable reactor connected in the center-tap return branch to effectively reduce peak operating voltages.