Arc welding machine

Abstract

When a gas protection metal electrode arc welding is carried out, because the voltage of the biggest load is higher, the arc suppression is difficult, and the operation is degenerated obviously during an intermittent weld. Therefore, the invention provides an arc welding machine, comprising a DC power supply circuit which rectifies and smoothes a commercial AC; an inverter circuit which transforms the DC voltage into a high frequency AC voltage; a main transformer of which the high frequency AC voltage is transformed into an AC voltage suitable for welding; a secondary rectification circuit which rectifies the output of the main transformer; an output current detection circuit which detects the rectified output current; a main control circuit which controls the inverter circuit according to the output current; and also an output voltage detecting circuit which detects a rectified output voltage. The main control circuit outputs a current detection value during the action of the inverter circuit to exceed a predetermined output current reference value, and after a preset-time, when an output voltage detection value is greater than a predetermined output voltage reference value, the action of the inverter circuit stops a predetermined time.

Description

technical field [0001] The present invention relates to a technical solution related to the control at the end of welding of gas metal arc welding (coated arc). Background technique [0002] In gas metal arc welding with an arc welding machine, arc extinction cannot be easily performed in tack welding in which arc ignition and arc extinction are repeated due to high maximum load voltage. [0003] Figure 5 It is the electrical connection diagram of the arc welding machine in the prior art. exist Figure 5 Among them, a DC power supply circuit is formed by a primary rectification circuit DR1 and a smoothing capacitor C1. The primary rectification circuit DR1 rectifies an AC power supply AC to generate a rectified voltage, and the smoothing capacitor C1 smoothes the rectified voltage with a pulsating flow to generate a DC voltage. [0004] The inverter circuit of the full bridge is formed by the first switching element TR1 to the fourth switching element TR4, and converts the...

AI Technical Summary

Problems solved by technology

[0011] However, in the prior art, a tap is required separately for the secondary side coil of the main transformer INT, and it is also necessary to select a switch or a thyristor element corresponding to a large current of the tap, so that the structure becomes complicated and the material cost increases.

[0012] Furthermore, in intermittent welding in which the manual electrode is frequently withdrawn and pulled down to repeat arc extinction and arc ignition, although the arc interruption performance becomes good, conversely, since the maximum load voltage is lowered, the startability of the arc is slightly reduced. In addition, the output cable cannot obtain sufficient arc voltage due to the long-term voltage drop of the cable, so the welding performance will also decline somewhat.

Images