Operation, Feeding wire electrode, Idle roll pressure setting – Lincoln Electric POWER MIG 255 SVM144-B User Manual
Page 18: Warning
POWER MIG 255
OPERATION
B-6
B-6
TO START THE WELDER
Turn the Power Switch switch to ON. This lights the red
LED display lights. With the desired voltage and wire
speed selected, operate the gun trigger for welder out-
put and to energize the wire feed motor.
FEEDING WIRE ELECTRODE
When triggering, the electrode and drive mecha-
nism are electrically “hot” relative to work and
ground and remain “hot” several seconds after the
gun trigger is released.
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NOTE: Check that drive rolls, guide plates, and gun
parts are proper for the wire size and type being used.
Refer to Table C.1 in Accessories section.
1. Turn the Readi-Reel or spool until the free end of
the electrode is accessible.
2. While securely holding the electrode, cut off the
bent end and straighten the first six inches. (If the
electrode is not properly straightened, it may not
feed properly through the wire drive system.)
3. Release the pressure on the idle roll by swinging
the adjustable pressure arm down toward the
back of the machine. Lift the cast idle roll assem-
bly and allow it to sit in an upright position. Leave
the outer wire guide plate installed. Manually feed
the wire through the incoming guide bushing and
through the guide plates (over the drive roll
groove). Push a sufficient wire length to assure
that the wire has fed into the gun and cable
assembly without restriction. Reposition the
adjustable pressure arm to its original position to
apply pressure to the wire.
4. Press gun trigger to feed the electrode wire
through the gun.
IDLE ROLL PRESSURE SETTING
The idle roll pressure adjustment knob is set at the fac-
tory at the #2 hash mark. This is an approximate set-
ting. The optimum idle roll pressure varies with type of
wire, wire diameter, surface conditions, lubrication, and
hardness. As a general rule, hard wires may require
greater pressure, and soft, or aluminum wire, may
require less pressure than the factory setting. The opti-
mum idle roll setting can be determined as follows:
1. Press end of gun against a solid object that is
electrically isolated from the welder output and
press the gun trigger for several seconds.
2. If the wire “birdnests”, jams, or breaks at the drive
roll, the idle roll pressure is too great. Back the
adjustment knob out 1/2 turn, run new wire
through gun, and repeat above steps.
3. If the only result was drive roll slippage, loosen the
adjustment knob on the conductor plate and pull
the gun cable forward about 6 in. (15 cm). There
should be a slight waviness in the exposed wire. If
there is not waviness, the pressure is too low.
Tighten the adjustment knob 1/4 turn, reinstall the
gun cable and repeat the above steps.
SETTING RUN-IN SPEED ON STAN-
DARD POWER MIG FEEDER
FAST OR SLOW RUN-IN MODE SELECTION
(When Timer Option is not installed)
The POWER MIG 255 is factory set for fast run-in
mode where the wire feed will accelerate directly to the
preset wire feed speed when the gun trigger is closed.
Slow run-in mode may also be selected, where it will
initially feed wire at 50 IPM until output current is
sensed or for 1.0 second, whichever occurs first. It will
then accelerate to the preset wire feed speed.
NOTE: See operating instructions for Timer Option Kit
if it is installed, as it provides its own run-in operation.
INSTRUCTIONS TO ENTER SLOW RUN-IN
1. Turn power OFF on front panel of POWER MIG
255.
2. Turn the wire feed speed dial fully counterclock-
wise to minimum.
3. With the gun trigger closed, turn the power ON at
the front panel of the POWER MIG 255.
4. The display will read “SLO run”.
INSTRUCTIONS TO ENTER FAST RUN-IN
1. Turn power OFF on front panel of POWER MIG
255.
2. Turn the wire feed speed dial fully clockwise to
maximum.
3. With the gun trigger closed, turn the power ON at
the front panel of the POWER MIG 255.
4. The display will read “FAS run”.
WARNING