Product Description; Recommended Processes And Equipment; Welding Capability; Limitations - Lincoln Electric POWER MIG 256 Operator's Manual

B-2

PRODUCT DESCRIPTION

The POWER MIG 256 is a complete semiautomatic
®
constant voltage DC arc welding machine built to meet
NEMA specifications. It combines a constant voltage
power source and a constant speed wire feeder with a
microcomputer-based controller to form a reliable high-
performance welding system. A simple control
scheme, consisting of continuous full range voltage
and wire feed speed controls, provides versatility with
ease of use and accuracy. The POWER MIG
Spool Gun ready and includes a second Gas Solenoid
for Spool Gun use. Refer to Accessories Section for
Applicable Spool Guns.
Other features include a 2" (51 mm) O.D. wire reel
spindle with adjustable brake, an integral gas cylinder
mounting undercarriage, an adjustable CO
blend flow regulator with cylinder pressure gauge and
inlet hose, a 15 ft. (4.6 m) Magnum
gun and cable, a 10 ft. (3.1 m) power cable with plug
(208/230V models only) and a 10ft. (3.1 m) work cable
with clamp.
The POWER MIG ® 256 features built in timer functions
that provide variable burnback control, a spot function,
a selectable 4-step trigger interlock and adjustable
"Run In" for wire starting optimization. Optional
features include a Dual Cylinder Mounting kit.
RECOMMENDED PROCESSES AND
EQUIPMENT
The POWER MIG ® 256 is recommended for GMA
welding processes using 10 to 44 lb (4.5 to 20 kg)
2"(51 mm) I.D. spools or Readi-Reel
optional adapter) of .025" through .045" (0.6 – 1.1 mm)
solid steel, .035" (0.9 mm) stainless, 3/64" (1.2 mm)
aluminum and .045" (1.1 mm) Outershield
Ultracore ® ; as well as .035" (0.9 mm) and .045" (1.1
®
mm) Innershield self-shielding electrodes.
The POWER MIG 256 is factory equipped to feed .035"
®
(0.9 mm) and .045(1.1mm) electrode. It also includes a
200A, 60% duty cycle (or 250A, 40% duty cycle) rated,
15 ft. (4.6 m) GMAW gun and cable assembly
equipped for these wire sizes. Use of GMAW
processes requires a supply of shielding gas.

WELDING CAPABILITY

The POWER MIG ® 256 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.
OPERATION
® 256 is
or Argon
2
®
PRO 250L GMAW
® coils (with
® and
POWER MIG ®

LIMITATIONS

POWER MIG ® 256 WILL NOT operate satisfactorily if
powered with a portable or in-plant generating system.

DESCRIPTION OF CONTROLS

See Figure B.1
1. Power ON/OFF Switch — Place the lever in the
"ON" position to energize the POWER MIG
When the power is on, the red LED display lights
illuminate.
2. 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.
3. 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.
4. Trigger Switch - Select the desired mode with the
toggle switch:
• Normal Welding mode (2 Step) provides weld
power only while the trigger switch is depressed.
• 4-Step Trigger interlock mode eliminates the need
to hold the gun trigger while welding. It operates in 4
steps:
1. Close trigger and establish welding arc.
2. Release trigger and continue welding.
3. Reclose trigger near end of weld.
4. Release trigger again to stop welding.
If the arc is broken while using this feature, the
machine will reset to the "trigger off" condition
automatically.
Note: 4 Step Trigger interlock mode does not function
with a Spool Gun.
5. Spot Time - Spot Weld Mode is used for tack
welding parts into position or for spot plug welds to
hold thin sheet metal together prior to manual stitch
or continuous welding. To use this feature, adjust
the On-Time (0-25 seconds) as appropriate to
obtain the desired results. Closing the trigger
initiates a single timed spot weld cycle.
Plug welds are made by using a punch to make a
3/16" (5 mm) diameter hole in the top sheet and arc
welding through the hole into the back sheet.
256
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® 256.