Welding Capability; Limitations; Description Of Controls; Wire Drive Roll - Lincoln Electric 11519 Service Manual

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WELDING CAPABILITY

The Power MIG® 255XT is rated at 250 amps @ 26
volts, at a 40% duty cycle based on a ten minute cycle
time. It is capable of higher duty cycles at lower output
currents and capable of up to 300 Amps at lower duty
cycles.

LIMITATIONS

The Power MIG® 255XT WILL NOT operate
satisfactorily if powered with a portable or in-plant
generating system.

DESCRIPTION OF CONTROLS

Power ON/OFF Switch — Place the lever in the "ON"
position to energize the Power MIG® 255XT. When the
power is on, the red LED display lights illuminate.
Voltage Control — This is a continuous control that
gives full range adjustment of power source output
voltage. It can be adjusted while welding over its 10 to
28 volt range.
Wire Speed Control — This controls the wire feed
speed from 50 – 700 inches per minute (1.2 – 17.8
m/min). The control can be preset on the dial to the
setting specified on the Procedure Decal on the inside
of the wire compartment door. Wire speed is not
affected when changes are made in the voltage
control.

WIRE DRIVE ROLL

The drive rolls installed with the Power MIG® 255XT
have two grooves one for .035(0.9mm) wire Solid Steel
electrode and the other for .045(1.2mm) wire. Drive roll
size is stenciled on each side of the drive roll. If feed-
ing problems occur, check to make sure that the wire
size and the drive roll size matches. See "Procedure
for Changing Drive Roll" in this section. This informa-
tion also appears on the Procedure Decal on the door
inside the wire compartment.
OPERATION

WIRE SIZE CONVERSION PARTS

The Power MIG® 255XT is rated to feed .025 through
.045" (0.6-1.2 mm) solid or cored electrode sizes.
The drive roll kits and Magnum 250L gun and cable
parts are available to feed different sizes and types of
electrodes. See Accessories section.
PROCEDURE FOR CHANGING
DRIVE AND IDLE ROLL SETS
1. Turn off the power source.
2. 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 assembly and
allow it to sit in an upright position.
3. Remove the outside wire guide retaining plate by
loosening the two large knurled screws.
4. Twist the drive roll retaining mechanism to the
unlocked position as shown below and remove the
drive roll. (See Figure B.1)
UNLOCKED POSITION
5. Remove the inside wire guide plate.
6. Replace the drive and idle rolls and inside wire
guide with a set marked for the new wire size.
NOTE: Be sure that the gun liner and contact tip are
also sized to match the selected wire size.
7. Manually feed the wire from the wire reel, over the
drive roll groove and through the wire guide and
then into the brass bushing of the gun and cable
assembly.
8. Replace the outside wire guide retaining plate by
tightening the two large knurled screws. Reposition
the adjustable pressure arm to its original position
to apply pressure. Adjust pressure as necessary.
Power MIG® 255XT
FIGURE B.1
LOCKED POSITION
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