AC Frequency
Depress the “SET AC” button (4) once. As shown in Fig 12, the
frequency light (4A) will flash and the amps display will flash
“F.AC”. While the display is flashing, the frequency will be
displayed in the “AMPS” digital display in Hz (Cycles per second).
Use the encoder (1) to adjust the AC frequency from 20 Hz to
200 Hz in 1 Hz increments while the display is flashing.
Higher
AC frequenc
ies
focus the arc cone more to a point and
give you greater arc control with less arc wandering.
Lower AC
frequencies increase the overall heat input in the material to
weld thicker sections of aluminum.
2G – Post Gas
–
Depressing the function button (2) until the
“post gas” light (2G) is illuminated will allow you to adjust the
post-gas flow. As shown in Fig 10, the post gas light (2G) is
illuminated and the amps display will flash “PrG”. While the
display is flashing, the post gas time will be displayed in the
“AMPS” digital display in seconds. Use the encoder to adjust
the post
gas from .1 sec to 30.0 sec in .1 sec increments while
the display is flashing.
Fig 10
Post gas is the amount of time the gas flows after the arc
has been extinguished. This ensures there will be no weld
contamination from the atmosphere while the weld puddle
cools, since the weld area will be purged with shielding gas
after welding. A good starting value is 6 sec. The larger the
tungsten diameter and the higher the amperage, the longer
the post gas flow needs to be.
3) AC Welding Mode
-
Depressing the AC welding mode
button (3) will illuminate the green “AC ON” light indicating
your Invertig 221 is in the AC welding mode as shown in Fig 11.
If the AC ON light is flashing, it indicates you have independent
AC amperage adjustment engaged.
Fig 11
To turn the AC Welding Mode off, depress the AC Welding
Mode button for at least 3 seconds until the green AC welding
mode light goes out.
For welding aluminum and magnesium, you want the “AC ON”.
For steel, stainless steel, 4130 tubing, and all other materials,
you want the AC welding mode off.
4) Set AC
The “Set AC” button (4) allows you to adjust the AC welding
parameters when the machine is in the AC welding mode.
The parameters which can be adjusted are AC Frequency,
AC Balance, Electrode Negative welding amperage and
Electrode Positive welding amperage.
Figure 11
8
3
Figure 10
1
2G
2
Chart 12a
In chart 12A you can see the effect the AC Frequency has on
the square wave. The 20 Hz wave is shown at the top. The
AC wave changes from electrode positive to electrode
negative 20 times a second. In the bottom you see a 200 Hz
wave – The AC wave changes from electrode positive to
electrode negative 200 times a second – 10 times faster than
the 20 Hz wave. The higher AC frequency focuses the arc
cone more to a point, allows you to maintain a point on the
tungsten, a gives you greater arc control with less arc wander-
ing. I try to picture this graph in my head when I change the
AC frequency so I can understand how I am changing the
wave and the arc characteristics.
1
4A
1
4
Figure 12
