Everlast PowerMTS 251Si Operator's Manual page 24

Section 2
"0.0" without severely affecting weld quality.
3. Pre-Flow and Post-Flow of Shielding Gas. Both
Pre flow and Post flow are functional in the MIG
and TIG welding processes. However, many MIG
welders do not provide Pre and Post flow of
shielding gas. This is a reason that many people
do not consider MIG for high quality welds,
where porosity must be minimized. By provid-
ing a Pre-flow and Post-flow of shielding gas in
MIG mode, the weld will be much cleaner, with
less porosity at both the beginning and the end
of the weld. Additionally the wire ball will not be
oxidized, reducing the need to trim the wire be-
fore starting. However, if you are trying to con-
serve MIG gas, the Pre and Post-flow time may
be set to "0.0" if the MIG welding is not of a criti-
cal nature. For best results, set Pre-flow time for
about .5 seconds and Post-flow time for at least
2 seconds. Add more time as amps are in-
creased if needed. While In TIG mode, Pre-flow
is required to prevent balling and oxidation of
the tungsten when the arc is struck. It also helps
to flood the area to be welded with shielding gas
before the arc is initiated. Post-Flow in TIG
mode is also essential to providing shielding of
the tungsten and weld as they cool together to
prevent oxidation of the tungsten and porosity in
the coalescing weld. As a starting point, set at
least .2 seconds Pre-Flow time. For Post-Flow set
approximately .5 seconds of Post-Flow for every
10-12 amps used. HINT: The arc start of both
MIG and TIG will be delayed until the Pre-Flow
time has been satisfied. This is not considered
to be a fault. The arc simply cannot be started
until the defined amount of Pre-flow time has
expired. If arc start feels excessively delayed,
check your Pre-Flow settings.
4. MIG and TIG Upslope/Downslope. This control
is active in both MIG and TIG modes. In the TIG
mode, the function is only necessary if you are
operating with the Torch switch instead of the
foot pedal. If operating in either TIG mode with
a foot pedal, set both Upslope and Downslope to
"0.0" if the programming allows. (Some program
versions may allow adjustment of slopes with the
foot pedal while others may block this feature
with the foot pedal.) In TIG mode, Upslope ad-
justs the amount of time it takes for the amps to
be raised from the minimum arc start amps to
the maximum selected amps. Start amps are
factory preset and this point is not adjustable.
Downslope is similar in TIG mode except it is the
Setup Guide and Component Identification
amount of time it takes for the unit to decrease
Amps from the maximum set amps to the mini-
mum arc termination amps. End amps where the
arc is terminated is factory pre-set and nonadjusta-
ble. For MIG operation, the up and down slope
functions are similar in concept, except the unit is
actually upsloping and downsloping voltage, in-
stead of amps. MIG Upslope works in conjunction
with the slow run in to help soften (or increase) the
run-in effect. For MIG Downslope, the goal is to
help aid in filling the weld crater. This is particular-
ly useful in the 4T setting of the final motion of the
trigger, to gradually cool the weld and fill the crater
just before the arc terminates. The amount of time
allowed for slope (Up or down) is different than TIG
because of the short run-in time that is pro-
grammed into the machine and the limited time
needed for crater filling. If the standard run-in is
satisfactory or standard operation is desired, either
of these settings may be kept at "0.0"
5. MIG Wire Speed, TIG and Stick Amps. Amperage,
simply described, controls penetration during
welding. Amp adjustment is allowed in all modes.
However in the standard MIG and spool gun
modes, Amps are controlled by adjusting the wire
feed speed rate (IPM). The faster the wire feeds
into the puddle, amperage will climb proportion-
ately according to the wire size. The larger the
diameter of the wire, the slower the wire needs to
feed to obtain the same amperage. In the same
manner, more wire speed is needed with a smaller
diameter wire to obtain an equal amp value of a
larger diameter wire. You will notice as you set up
the synergic mode that the unit displays selected
amperage instead of wire feed speed (IPM). This is
because the synergic mode, requires you to enter
the wire diameter and wire type. This allows the
welder's programming to accurately pre-figure
amps being set based off these two parameters.
Amps are a more accurate figure to use in this situ-
ation. Regardless of what process is selected, the
function of the display changes to reflect the
realtime amp output while welding. If adjustments
are completed, the unit will default to back to
Amps within a few seconds. If used in the Pulse
TIG mode, the unit will default to "TIG Pulse
Amps."
6. MIG Volts. Voltage dictates the height and width
of the bead while MIG welding. If Voltage are set
too low, the weld will appear ropey and cold and
the wire may even stub into the puddle. If the volt-
age is set too high, undercut may develop at
24