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6
WIG welding (optional)
Due to the same welding characteristics as with electrode welding, WIG welding is possible with Inverter welding
device ST 140/60 DC.
A WIG torch model SR 17 V is used, which is always connected to the negative (-) pole (5). The arc is ignited by
scratching with the tungsten electrode on the workpiece (causing a short-circuit).
The gas is supplied directly from the torch to the pressure reducer of the gas cylinder. A flow setting quantity of 6
- 7 l/min is recommended. Pure argon must be used as tinted glass.
The connection to the welding table and workpiece is made (4). The light arc current is pre-selected with the
potentiometer (2). Then the light arc is ignited by briefly striking the tungsten electrode on the workpiece.
6.1 Tips for WIG
To ensure good arc ignition and good welding results, comply with the following points:
Electrode typ
1
For example, use:
WT 20 1.8 - 2.2 % thorium, colour code red or
WC 20 1.8 - 2.2 % Ceroxide, colour code grey
Electrode diameter
2
The electrode diameter must correspond to the welding current.
Standard values:
Tungsten electrodes must be ground in longitudinal direction! Use a fine grinding wheel and grind from tip to
3
shaft.
4
Too much gas flow can deteriorate the arc ignition properties (arc extinguished by blowing).
7
Overload
The inverter welding machine ST 140/60 is protected against overloads by protection devices. If the permissible
duty cycle is exceeded, the machine shuts down automatically. This is indicated by the control lamp (3).
After a short cooldown period the machine is operational again.
Important: Do not switch off the machine during the cooldown period, as this will extend the cooldown period
considerably (fan on).
8
Trouble-shooting
During welding, the control lamp (3) lights up and
there is no current supply.
It is difficult to keep the light arc burning when
welding.
There is no welding current when device is switched
on.
Poor ignition with WIG welding
Pores in weld seams
below 80 A:
Diameter 1.0 mm
70 to 140 A:
Diameter 1.6 mm
- Electrode stored too long, is damp or damaged.
- Current supply too low (< 190 V at full load).
- Cable too long
- Check mains fuse
- Voltage too high (over 250 V), which triggers the
- insufficient or no tinted glass
- tungsten electrode wrongly ground
- wrong electrode diameter
- workpiece surface not clean
- incorrect setting of tinted glass flow quantity (too high
- incorrect tinted glass (only pure argon)
- dirty tinted glass
- wrong position of torch
Excess temperature protection is activated. Keep the
device switched on and wait for a few minutes.
corresponding protection device
or too low)
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