OVERVIEW
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2.2 Working Principle
The working principle of MIG SERIES arc welding machine is shown as the following figure.
Single-phase 220V work frequency AC is rectified into DC
（
350V
）
, then is converted to medium
frequency AC (about 40KHz) by inverter device (IGBT), after reducing voltage by medium
transformer (the main transformer) and rectifying by medium frequency rectifier (fast recovery
diodes), and is outputted by inductance filtering. The circuit adopts current feedback control
technology to insure current output stably when MMA or TIG. And adopts voltage feedback
control technology to insure voltage output stably when MIG. Meanwhile, the welding current
parameter can be adjusted continuously and infinitely to meet with the requirements of welding
craft.
2.3 Volt-Ampere Characteristic
MIG SERIES welding machine has an excellent volt-ampere characteristic, whose graph is shown as the
following figure. The relation between the rated loading voltage U
2
and welding current I
2
is as follows:
U
2
=14+0.05I
2
(V)
Current sensor
