User Manual
Version 1.0k of 11.06.2019
Original manual
PONTIG 202 AC/DC MOST
-17-
To choose the method press button (
12
), the diode (
10
) lights up (see figure 4).
In the TIG DC Pulse method, all TIG parameters are available, but the welding current consists
of two components: Ip and Ib. Four parameters are subject to regulation. Description below
according to the Figure 9:
- Peak current (Ip):
current in amperes at time tp according to the customer’s welding technolo-
gy.
- Background current (Ib):
current in amperes at time tb according to client welding technology.
- Pulse rate (1/T):
according to the formula T = tp + tb. value according to client welding techno
-
logy, range of 0.2-200 Hz (see Fig. 12).
- Peak current time factor (100% * tp / T):
percentage of peak current in the pulse period,
value according to client welding technology, range 10-90%.
8.3 TIG AC welding
tc
tp
I0
I2
0
I1
tu
td
I0 - Initial current; I1 - welding current; I2 - final current, tu - upslope time; td - downslope time
tp - alternating current (AC) period; tc - positive electrode time
Figure 13: Alternating current flow TIG AC square wave
To choose the method press button (
12
), the diode (
7
) lights up (see figure 4).
In the case of TIG AC welding, the gas pre-flow time and the outflow time are the same
as in DC TIG welding. Other parameters are described below (according to figure 12):
- Initial current (I0 - range 5 - 160A), welding current (I1) and final current (I2):
The preset
value of three parameters is the average (average deviations) of the welding current, values
according to the user’s welding requirements.
- Pulse rate (1/tp):
value according to the user’s welding requirements, range 20-
250 Hz
- AC balance (100% * tc / tp).
The ratio of negative and positive current within Alternating
Current affecting welding speed and weld cleanness for aluminium and its alloys, range 20 -
80%. In the alternating current, the negative electrode is responsible for cleaning the weld from
oxides generated during welding. Its high percentage slows down welding and causes faster
electrode wear, the weld pool is wide and shallow. Usually the share of the negative electrode
is 10-40% of the total. The positive electrodes of the AC current increases the welding speed,
the welding arc is more concentrated, the penetration is deeper.