Maintenance, Safety precautions, Routine and periodic maintenance – Lincoln Electric POWER MIG 255 SVM144-B User Manual
Page 26: Warning drive rolls and guide tubes, Cable cleaning, Gun tubes and nozzles, Caution
POWER MIG 255
MAINTENANCE
D-2
D-2
SAFETY PRECAUTIONS
• Have a qualified electrician do the maintenance
and troubleshooting work.
• Disconnect the input power off using the dis-
connect switch at the main input supply before
working inside machine.
• Unplug the power cable if it is connected to a
receptacle.
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Read the Safety Precautions in the front of this manu-
al before working on this machine.
ROUTINE AND PERIODIC
MAINTENANCE
1. Disconnect input AC power supply lines to the
machine before performing periodic maintenance,
tightening, cleaning, or replacing parts.
Perform the following daily:
1. Check that no combustible materials are in the
welding or cutting area or around the machine.
2. Remove any debris, dust, dirt, or materials that
could block the air flow to the machine.
3. Inspect the electrode cables for any slits, punc-
tures in the cable jacket, or any condition that
would affect the proper operation of the machine.
Perform Periodically:
Clean the inside of the machine with low pressure air
stream. Clean the following parts. Refer to Figure D.1.
Main transformer and output choke.
Power enhancement choke.
Wire drive assembly.
Capacitor bank.
SCR rectifier bridge and heat sink fins.
Fan motor assembly.
Control printed circuit board.
Snubber printed circuit board.
NOTE:
The fan motor has sealed bearings which
require no maintenance.
WARNING
DRIVE ROLLS AND GUIDE TUBES
After every coil of wire, inspect the wire drive mecha-
nism. Clean it as necessary by blowing with low pres-
sure compressed air. Do not use solvents for cleaning
the idle roll because it may wash the lubricant out of
the bearing. All drive rolls are stamped with the wire
sizes they will feed. If a wire size other than that
stamped on the roll is used, the drive roll must be
changed.
CABLE CLEANING
Clean the cable liner after using approximately 300
pounds (136 kg) of electrode.
1. Remove the cable from the wire feeder and lay it
out straight on the floor.
2. Remove the contact tip from the gun.
3. With an air hose at the gas diffuser end, use low
pressure to gently blow out the cable liner.
Excessive pressure at the start may cause the dirt to
form a plug.
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4. Flex the cable over its entire length and again blow
out the cable.
5. Repeat this procedure until no more dirt comes
out.
GUN TUBES AND NOZZLES
1. Replace worn contact tips as required.
2. Remove spatter from the inside of the gas nozzle
and tip every 10 minutes of arc time or as required.
CAUTION