Fronius TransTig 2200 Comfort - Page 134

134
"P" parameter (constant welding power)
- If the “P” parameter is set, the welding power is kept constant, irrespective of the weld-
ing voltage and welding current. This results in a hyperbolic characteristic (6).
- The “P” parameter is particularly suitable for cellulose electrodes.
The characteristics (4), (5) and (6) shown here apply when using a rod electrode whose
characteristic corresponds - at a given arc length - to the load line (1).
Depending on what welding current (I) has been set, the point of intersection (operating
point) of characteristics (4), (5) and (6) will be displaced along the load line (1). The oper-
ating point provides information on the actual welding voltage and the actual welding cur-
rent.
Where the welding current (I
1
) is permanently set, the operating point may migrate along
the characteristics (4), (5) and (6) depending on the welding voltage at that moment in time.
The welding voltage U is dependent upon the length of the arc.
If the arc length changes (e.g. in accordance with the load line (2)) the resulting operating
point will be the point where the corresponding characteristic (4), (5) or (6) intersects with
the load line (2).
NOTE! When setting a flat characteristic (5), set the arc-force dynamic to a higher
value.
NOTE! If there are problems with a rod electrode tending to "stick", set the arc-
force dynamic to a higher value.
(1) Load line for rod electrode
(2) Load line for rod electrode where arc length is in-
creased
(3) Load line for rod electrode where arc length is re-
duced
(4) Characteristic where "CON" parameter is select-
ed (constant welding current)
(5) Characteristic where "0.1 - 20" parameter is se-
lected (drooping characteristic with adjustable
slope)
(6) Characteristic where "P" parameter is selected
(constant welding power)
(7) Example of pre-set arc-force dynamic where
characteristic (5) or (6) is selected
(8) Possible change in the current where character-
istic (5) or (6) is selected, as a function of the
welding voltage (arc length)
(a) Operating point where arc length is long
(b) Operating point when welding current IH is set
(c) Operating point where arc length is short
Setting example: I1 = 250 A, arc-force dynamic = 50
Applies to characteristics (5) and (6): Depending upon the welding voltage (arc length),
the welding current (I) will also become either smaller or larger, even though the value set
for I
1
remains the same.
10
20
30
40
50
60
U (V)
004003001 200
I (A
)
I
1
+ DynamikI
1
- 50 %
(8)
(2)
(1)
(3)
(7)
(c)
(c)
(b)
(a)
(a)
(6)
(5)
(4)