REHM TIGER DIGITAL 180 AC/DC ULTRA, Operating Instructions Manual

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Function description
36
6.2 AC settings menu
The AC settings menu [ BF7 ] is only visible on AC devices.
Depending on the equipment variant, further functions are restricted, ( Table 2 ).
6.2.1 AC waveform
Selection between sinus, rectangle and triangle waveforms.
In the
Auto setting, the waveform is set automatically.
6.2.2 AC frequency (Hz)
The frequency value determines how fast the output polarity reversal takes place
one after the other. The setting range extends from 30 Hz to 300 Hz.
For example, at a frequency of 200 Hz the polarity reversal at the output socket
from plus to minus and back occurs every 5ms (=0.005 seconds).
The welding current drops to zero with every polarity reversal, ignites again in the
opposite direction and increases to the set welding current.
The adjustable frequency when AC welding, results in a considerable noise
reduction and improvements in the alternating current welding.
The REHM patented automatic frequency control can be selected as a special
feature for TIG AC current welding.
The frequency is set to "Auto" for activation.
The automatic frequency control developed by REHM combines the benefits of a
very stable arc in the lower welding current range with the benefits of a high
electrode capacity in the high current range.
The AC frequency is automatically adjusted to the actual momentary value of the
welding current.
Normally, the selection of automatic frequency control makes setting the
frequency superfluous. This setting option provides unlimited flexibility other than
a few special application-specific cases where it is desirable to use a frequency
that is different to that selected by the automatic frequency control.
6.2.3 AC balance ( )
The AC balance setting option is only available with AC current welding with TIG.
It ranges from -5 to +5 and enables the arc to be influenced as well as the
penetration and cleaning when welding aluminium over a very large range.
In the centre position (0) the negative and positive welding current is equally
distributed over time.
With an increasing positive value the share of the positive welding current
increases (up to +5) and the negative share reduces. The cleaning of the weld
pool is improved by the positive share. The arc is wider and heat penetration less
deep.
With an increasing negative value the share of the negative welding current
increases (up to -5) and the positive share reduces. This makes the arc more
narrow and generates a deeper weld penetration at the same time as a low
electrode load.
The use of the highest possible negative value whilst maintaining a sufficient
cleaning effect is recommended.
6.2.4 Further settings for DualWave
The AC setting menu [ BF7 ] is augmented by the setting options for