| 摘要 |
PURPOSE:To make the controlling of the secondary voltage waveform effective for welding in a short time electricity conduction possible by applying a reverse voltage to one of control rectifying elements coupled respectively to the voltage changing taps on the primary side of a welding transformer to extinguish its arc and commutating the same to the other. CONSTITUTION:If in an electric power sourceI-II (a) firing signal is applied to a thyristor (THY)A from a firing circuit, the secondary voltage waveform 6 8 appears from a welding transformer 12. Here, a THYB is fired by the firing signal of the firing circuit. Then, the primary voltage of the transformer is higher with the other tap T1 than one tap T2 by the effect of the transformer 12. Since the anode voltage to be applied upon the cathode of the THYA is the differential voltage of the taps T1 and T2 as a negative voltage, the THYA is extinguished and the THYB fires. The commutation of the THYB continues to fire until the current conduction period determined by the reactance of the welding machine. In the period (a), the voltage waveform 6 8 9 appears accordingly. The same procedure is held in the period (b) where the power source inverts. |
