Lincoln Electric 11141 Service Manual page 31

OPERATION
B-9 B-9
PULSE WELDING
FIGURE B.3
CURRENT WAVE FORM (PULSE)
Pulse welding procedures are set by controlling an
overall "arc length" variable. When pulse welding, the
arc voltage is highly dependent upon the waveform.
The peak current, back ground current, rise time, fall
Current
time and pulse frequency all affect the voltage. The
exact voltage for a given wire feed speed can only be
predicted when all the pulsing waveform parameters
are known. Using a preset voltage becomes impracti-
cal, and instead the arc length is set by adjusting
"trim".
Time
Trim adjusts the arc length and ranges from 0.50 to
1.50, with a nominal value of 1.00. Trim values greater
than 1.00 increase the arc length, while values less
than 1.00 decrease the arc length.
All pulse welding programs are synergic. As the wire
feed speed is adjusted, the Power Wave ® will automat-
ically recalculate the waveform parameters to maintain
similar arc properties.
The Power Wave utilizes "adaptive control" to com-
®
pensate for changes in electrical stick out while weld-
ing. (Contact to Work Distance is the distance from the
contact tip to the work piece.) The Power Wave wave
®
forms are optimized for a 0.75" (19mm) stick-out. The
adaptive behavior supports a range of stickouts from
0.50" (13mm) to 1.25" (32mm). At very low or high wire
feed speeds, the adaptive range may be less due to
reaching physical limitations of the welding process.
Arc Control, often referred to as wave control, in pulse
programs usually adjusts the focus or shape of the arc.
Wave control values greater than 0.0 increase the
pulse frequency while decreasing the background cur-
rent, resulting in a tight, stiff arc best for high speed
sheet metal welding. Wave control values less than 0.0
decrease the pulse frequency while increasing the
background current, for a soft arc good for out-of-posi-
tion welding.
POWER WAVE ® 355M/405M