Maintenance; Safety Precautions; Routine; Periodic - Lincoln Electric 12442 Operator's Manual

D-1

MAINTENANCE

Safety Precautions

WARNING
ELECTRIC SHOCK can kill.
• Do not touch electrically live parts
such as output terminals or inter-
nal wiring.
• When inching with gun trigger, electrode and
drive mechanism are "hot" to work and ground
and could remain energized several seconds
after the gun trigger is released.
• Turn OFF input power at welding power source
before installation or changing drive roll and/or
guide tubes.
• Welding power source must be connected to
system ground per the National Electrical Code
or any applicable local codes.
• Only qualified personnel should perform mainte-
nance work.
------------------------------------------------------------------------
Observe all additional Safety Guidelines detailed
throughout this manual.
ROUTINE MAINTENANCE
• Clean and tighten all weld terminals.
• Inspect all weld cables, control cables, gun cables
and shielding gas hoses. Repair or replace as nec-
essary.
PERIODIC MAINTENANCE
•
Clean drive roll grooves.
• Blow out or vacuum the inside of the feeder.

CALIBRATION SPECIFICATION

WARNING
ELECTRIC SHOCK can kill.
• Do not touch electrically live parts.
• When inching with the gun trig-
ger, electrode, wire drive motor
and drive mechanism are "hot" to
work and ground and could
remain energized several seconds
after the gun trigger is released.
• Welding power source must be
connected to system ground per
the National Electrical Code or
any applicable local codes.
• Only qualified personnel should perform mainte-
nance work.
------------------------------------------------------------------------
MAINTENANCE
Calibration of the LF-74 may be required when the
p.c. board, potentiometer or motor is replaced or ser-
viced. Calibration matches the scale on the name
plate to the actual wire feed speed.
To verify the wire feed speed,
1. Assemble a .045 (1.2 mm) drive roll kit to the feed-
er.
2. Load .045 (1.2 mm) steel wire into the feeder.
3. Trim the wire to the end of the contact tip of the
gun.
4. Adjust the WFS knob per the Table D.1.
TABLE D.1
K2426-6, K2426-7
5. Activate and hold the COLD FEED switch for 10
seconds.
6. Measure the length of wire extending from the con-
tact tip. The wire length shown in Table D.2.
MODEL
K2426-6
K2426-7
LF-74
MODEL WFS knob setting
300
WIRE LENGTH
50 inches ± 5 inches (1270 mm ± 127 25mm)
D-1