-
Parameter "0.1 - 20" is used to set a drooping characteristic (5). The setting
range extends from 0.1 A / V (very steep) to 20 A / V (very flat).
-
Setting a flat characteristic (5) is only advisable for cellulose electrodes.
P-constant (constant welding power)
-
If the "P-constant" parameter is set, the welding power is kept constant, irre-
spective of the welding voltage and welding current. This results in a hyper-
bolic characteristic (6).
-
The "P-constant" parameter is particularly suitable for cellulose electrodes,
as well as for arc air gouging.
-
For arc air gouging, set the arc-force dynamic to "100".
10
20
30
40
50
60
U (V)
004003001 200
I (A)
I
H
+ DynamikI
H
- 50 %
(8)
(2)
(1)
(3)
(7)
(c)
(c)
(b)
(a)
(a)
(6)
(5)
(4)
(1) Load line for rod electrode
(2) Load line for rod electrode
where arc length is increased
(3) Load line for rod electrode
where arc length is reduced
(4) Characteristic where "I-con-
stant" parameter is selected
(constant welding current)
(5) Characteristic where "0.1 - 20"
parameter is selected (drooping
characteristic with adjustable
slope)
(6) Characteristic where "P-con-
stant" parameter is selected
(constant welding power)
(8) Example of pre-set arc-force dynamic where characteristic (5) or (6) is se-
lected
(9) Possible change in the current where characteristic (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 where welding current I
H
is set
(c) Operating point where arc length is short
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 operating point provides information on the actual welding voltage
and the actual welding current.
Where the welding current (I
H
) is permanently set, the operating point may mi-
grate along the characteristics (4), (5) and (6) according to the welding voltage at
a given moment. The welding voltage U is dependent upon the arc length.
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).
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
H
remains the same.
118
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