Everlast PowerMTS 251Si Operator's Manual page 43

Section 3
times referred to as pulse balance, as it
indeed can be used to "balance" the time
the pulse spends in base and the peak
stages. Always remember that pulse time-
on only has a specific observable effect on
the weld puddle if the other two settings
remain unchanged while the pulse time-on
is being adjusted. Increasing the pulse
time-on will result in faster wet in, but can
lead to overheating of the weld metal and
filler wire if adjusted too high. Adjusted
too low, the weld will become cold and the
arc may become rough. When welding
with a low welding voltage and or low
pulse frequency, the arc may appear to go
completely out between the pulses if the
pulse time-on is not adjusted to 80% or
above (or if the pulse frequency is not in-
creased to above 20-30 Hz.) This will pro-
vide for a majority of peak voltage time
during the weld, but still render the defi-
nite rapid cooling effect needed for weld-
ing thin materials. For general purpose
welding, select a value of somewhere be-
tween 50% and 80%. If welding at a higher
welding voltage, you may find that a lower
pulse time-on value offers a greater freeze
effect. Note: if you are attempting to use
this for pulse spray mode, your pulse time
-on value combined with your frequency
setting should roughly equal one droplet
of filler metal per pulse cycle for best re-
sults. Admittedly, this may not be a
measurable to the naked eye. However,
when the pulse spray mode is correctly set,
you will be able to see the effects and the
actual transfer of wire across the arc in the
form of fast-moving molten droplets with-
out the wire digging deep into the puddle
or cracking. More simply put, the pulse
spray mode will be better if the time-on is
PULSE MIG OPERATION
Basic Theory and Function
set for a briefer period of time rather than
a longer period of time to prevent the wire
from being fed into the puddle as it crosses
the threshold into the colder portion of the
pulse cycle (short circuit). Pulse time-on is
critical to determining how much wet-in
the peak stage of the pulse is providing. It
contributes to travel speed as well. In-
creasing pulse time-on will increase fluidity
and travel speed. As a good starting point
for all types of pulse use, pulsed spray or
short circuit, start with a setting of 50-75%.
Begin at your chosen setting and slowly
increase the setting values. Pulse time-on
settings below 50% will generally be rarely
used. Lower pulse time-on settings be-
tween 75% and 50% are useful in control-
ling warping. But again, that is going to be
dependent upon the application and the
performance goal of the user. Some ex-
perimentation below the 50% mark may
prove useful in some circumstances.
4. MIG Inductance/Arc Force (%). Even
though Arc force/Inductance has already
been covered in this manual, this will ulti-
mately prove helpful in the final stage of
tuning the pulse. For steel/stainless use,
the inductance should be set at 65-70%
before pulse adjustment is made. Then
after all adjustments are made, use the
inductance control to improve arc charac-
teristics. Adjustment of only 1 or 2% can
make a difference when welding on thin
gauges of metal. As an example, on stain-
less, the puddle is typically defined as slug-
gish and lazy, making everything in the
puddle seem cold. However, if too much
voltage is used to make the bead wet in
faster, the surrounding material may over-
heat and warp. In these cases a faster
travel speed is not supported due to slow
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