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B-9
WARNING
When using an open arc process, it is necessary to use
correct eye, head, and body protection.
8. Position electrode over joint. End of electrode may
be lightly touching the work.
9. Lower welding helmet, close gun trigger, and begin
welding. Hold the gun so the contact tip to work dis-
tance is about 3/8" (10 mm) [3/4" (20 mm) for
Outershield].
10. To stop welding, release the gun trigger and then
pull the gun away from the work after the arc goes
out.
11. When no more welding is to be done, close valve
on gas cylinder (if used), momentarily operate gun
trigger to release gas pressure, and turn off
POWER MIG 255C.
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 gun cable as straight as possible when
welding or loading electrode through cable.
c. Do not allow dolly wheels or trucks to run over
cables.
d. Keep cable clean by following maintenance
instructions.
e. Use only clean, rust-free electrode. The Lincoln
electrodes have proper surface lubrication.
f.
Replace contact tip when the arc starts to become
unstable or the contact tip end is fused or
deformed.
OPERATION
g. Keep wire reel spindle brake tension to minimum
required to prevent excess reel over-travel which
may cause wire "loop-offs" from coil.
h. Use proper drive rolls and wire drive idle roll
pressure for wire size and type being used.
FAN CONTROL
The fan is designed to come on automatically when a
weld arc is established. The fan will stay on for a
minimum of 6 minutes after the weld arc is terminated.
The fan will also stay on when the machine's welding
and feeding are disabled during thermostatic over
temperature protection. (See Welding Thermal
Overload Protection)
INPUT LINE VOLTAGE PROTECTION
High Line Voltage — If the line voltage exceeds 125%
of rated input voltage, the output will be reduced to the
lower level to protect voltage rating of the capacitor
bank.
Low Line Voltage — You may not be able to get
maximum output from the machine if the line voltage is
less than rated input. The unit will continue to weld,
but the output may be less than what is set.
WIRE FEED OVERLOAD
PROTECTION
The POWER MIG 255C has solid state overload
protection of the wire drive motor. If the motor becomes
overloaded, the protection circuitry turns off the wire
feed speed weld outputi and gas solenoid. Check for
proper size tip, liner, and drive rolls, for any
obstructions or bends in the gun cable, and any other
factors that would impede the wire feeding.
To resume welding, simply pull the trigger. There is no
circuit breaker to reset, as the protection is done with
reliable solid state electronics.
POWER MIG 255C
B-9
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