Lincoln Electric SQUARE WAVE TIG 355 Service Manual page 25

B-9
Example: The Peak Current control is preset at 50
amps and the Amptrol is partially down, giving a
peak current of 30 amps.
Current control is set at 50%, the Background (low
pulse) current will be 15 amps.
The Amptrol raises and lowers the Peak current.
Since Background current is always a percentage
of Peak current, the Amptrol also raises and lowers
the Background current.
Pulse % On — Controls the percentage of the
pulse cycle that is at the Peak current.
Example: You are pulsing at 1 Pulse per second
with a 30% Pulse % On setting. The welding cur-
rent would be at the Peak current for 0.3 seconds
and at the Background current for the remainder of
the cycle, 0.7 seconds.
16. CRATER FILL CONTROLS
Use the Crater Fill controls to automatically control
current fade-out at the end of a weld. LOCAL cur-
rent control (Item 1) MUST be used when Crater
Fill is used.
Crater Fill Switch — A two-position toggle switch.
ON: Crater Fill Fade-out will begin when the Arc
Start Switch or Amptrol is released (2-Step mode)
or pressed and released a second time (4-Step
mode). If used with Spot Time (item 13), Crater Fill
begins at the end of the Spot Time. The current
control (item 1) switch must be in LOCAL when
using Crater Fill.
OFF: Locks out Crater Fill controls.
FIGURE B.2 – STATUS INDICATOR LIGHT SEQUENCE SQUARE WAVE TIG 355
OPERATION
If the Background
17. STATUS INDICATOR LEDs — Seven Light
SQUARE WAVE TIG 355
Fade-out Control — Controls how slowly the cur-
rent fades out. The FAST setting will cause current
to ramp down from the welding current toward 2
amps in approximately 1/2 second; the SLOW set-
ting, in approximately 20 seconds. The time for
downslope to the Crater Fill Current level depends
on the difference between the weld current and the
Crater Fill Current.
Crater Fill % Peak Current Control — Controls
the final Crater Fill current from zero to 100% of the
weld current preset on the Peak Current control.
Example: With a Crater Fill % Current setting of
20% and a weld current preset at 100 amps, the
current will fade from 100 amps to 20 amps and
then dwell at 20 amps for about 1-1/2 seconds
before the arc goes out.
The final Crater Fill current dwell time is approxi-
mately 1-1/2 seconds, regardless of Crater Fill
control settings.
Emitting Diodes (LEDs) which light when their
function is active.
• GAS & WATER LED is on when the solenoid
valves are open, from the beginning of Preflow to
the end of Afterflow.
• HIGH FREQUENCY LED is on when the high
frequency circuit is on.
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