C-1
OPERATION
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MAGNUM® PRO 350, 450 AND 550 DUAL PROCEDURE & DUAL SCHEDULE
ELECTRODES AND EqUIPMENT
The MAGNUM
®
PRO DP and DS and cables have
been designed for use with Lincoln L-50 and Super
Arc L-56, solid steel wire electrodes for the GMAW
process and Lincoln Outershield7 cored electrodes for
the gas-shielded FCAW process. Refer to the appro-
priate Lincoln Process and Procedure Guidelines for
the electrode used for information on recommended
electrical and visible stickouts.
MAKING A WELD
Do not attempt to use this equipment until you
have thoroughly read all operating and mainte-
nance manuals supplied with your machine. They
include important safety precautions, detailed
engine starting, operating and maintenance
instructions and parts lists.
ELECTRIC SHOCK can kill.
• Do not touch electrically live parts
such as output terminals or inter-
nal wiring.
• Insulate yourself from the work and
ground.
• Always wear dry insulating gloves.
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FUMES AND GASES can be danger-
ous.
• Keep your head out of fumes.
• Use ventilation or exhaust to
remove fumes from breathing zone.
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WELDING SPARKS can cause fire or
explosion.
• Keep flammable material away.
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ARC RAYS can burn.
• Wear eye, ear and body protection.
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Only qualified personnel should operate this
equipment.
a. Check that the welding power source is on and that
the shielding gas supply is set for the proper flow rate.
b. For the MAGNUM
®
PRO DP switch set the rocker
switch to the desired procedure.
c. Position electrode over joint. End of the electrode
should be slightly off the work.
d. Lower welding helmet. close gun trigger and begin
welding. Hold the gun so the contact tip to work dis-
tance gives the correct electrical stickout as required
for the procedure being used.
e. To stop welding, release the gun trigger and then pull
the gun away from the work after the arc goes out.
Follow wire feeder instruction manual if using a trigger
interlock circuit.
f. When using MAGNUM
®
PRO DS gun and cable, the
trigger operates as follows:
-Pulling the trigger in part of the way will engage the
first procedure set at the feeder.
-Pulling the trigger the rest of the way will engage the
second procedure.
If the optional interlocking trigger is installed,
-With the trigger pulled in all the way, the trigger can
be slid forward into the interlock position.
-To release interlock, squeeze trigger and pull back.
g. When using the MAGNUM
®
PRO DP switch, the trig-
ger only starts and stops the welding. The procedure
is changed by actuating the rocker switch that is built
into the top of the gun.
AVOIDING WIRE FEEDING PROBLEMS
Wire feeding problems can be avoided by observing the
following gun handling procedures:
a. Do not kink or pull cable around sharp corners.
b. Keep the electrode cable as straight as possible when
welding or loading electrode through cable.
c. Avoid wrapping excess cable around handle or front
of wire feeder especially on longer 20 and 25 ft (6.1
and 7.6 m) length guns.
d. Do not allow dolly wheels or trucks to run over cables.
e. Keep cable clean by following maintenance instruc-
tions.
f. Use only clean, rust-free electrode. The Lincoln elec-
trodes have proper surface lubrication.
g. Replace contact tip when the arc starts to become
unstable or the contact tip end is fused or deformed.
WARNING