38
In older machines, a balanced current output wave was achieved using a large number of capacitors in series or
a battery in the welding circuit. Modern TIG power sources use electronics to create and maintain a balanced
wave and now most AC TIG power sources produce a square wave current output.
A square wave power supply can change the current from ele positive to electrode - negative very quickly.
This produces high voltage as the current switches polarities allowing the arc to restart easily. The arc can be
maintained without the use of high-frequency or any other arc stabilising methods.
The output current and voltage are controlled electronically so the balance between the amount of current elec-
trode positive and the amount of current electrode negative can be adjusted. This allows the welder to adjust
the amount of cleaning and the amount of penetration. This is achieved electronically by adjusting the balance
control dial on the welding machine. More current flow from the + polarity produces stronger arc energy and cur-
rent flow from the tungsten and is good for removing the oxidized surface of the work piece. However too much
+ current flow can drive too much energy to the tungsten causing it to overheat and melt the tungsten electrode.
BALANCED SQUARE WAVE FORM
Balance Adjusted for More Oxide Cleansing Action - Hotter Tungsten
Balance Adjusted for More Penetration - Cooler Tungsten
reverse polarity
current
straight polarity
EVEN BALANCE
Even Penetration - Stable Arc
LESS POSITIVE
BALANCE
More Penetration - Faster Welding
More Electrode Capacity
MORE POSITIVE
BALANCE
Less Penetration - Oxide Cleaning
Less Electrode Capacity
EVEN BALANCE
Even Penetration - Stable Arc
LESS POSITIVE
BALANCE
More Penetration - Faster Welding
More Electrode Capacity
MORE POSITIVE
BALANCE
Less Penetration - Oxide Cleaning
Less Electrode Capacity
EVEN BALANCE
Even Penetration - Stable Arc
LESS POSITIVE
BALANCE
More Penetration - Faster Welding
More Electrode Capacity
MORE POSITIVE
BALANCE
Less Penetration - Oxide Cleaning
Less Electrode Capacity
current
current
straight polarity
reverse polarity
current
AC TIG Welding - AC Wave Balance Control
Razor
32OAC/DC
TIG-MMA
AC TIG WELDING GUIDE
54
Summary of Contents for Xcel-Arc MULTI 230 AC/DC
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