Product Description - Lincoln Electric LF-74 Operator's Manual

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PRODUCT DESCRIPTION

General Physical Description
The LF-74 is optimized for GMAW and FCAW weld-
ing. The powerful 4 roll MaxTrac™ drive, heavy duty
enclosure and wire reel stand combine to make an
easy to install, easy to use wire feeder for everyday
welding. Powering the wire drive is a high perfor-
mance motor gearbox. A heavy duty hinged door
opens easily, which provides an ample amount of
room for assembling precision drive components and
the welding gun.
MaxTrac™ technology delivers great feeding
because:
• Patent pending drive rolls improve traction.
• The precision machined, rigid aluminum alloy frame
results in maximum drive roll clamping pressure.
• Drive hubs with steel inner cores have 3 ball bear-
ings inside each hub.
• The drive hubs are supported by large, heat treated
and ground shafts for maximum rigidity and accu-
rate drive roll alignment.
• Patent pending dual spring pressure arms have
sensitivity for feeding soft wires without crushing
them, and have plenty of compression force for
feeding solid or stiff wires.
Easy to configure, easy to service parts give
MaxTrac™ drives the edge in productivity.
• Patented split wire guides fully support the wire and
virtually eliminate birdnesting.
• No tools required to change the drive rolls and wire
guides.
• Changeable gun bushings easily accept guns from
many manufacturers.
• Brass-to-brass connections between the electrode
connection and the gun minimize voltage drop varia-
tions, resulting in consistent arc performance all
day, every day.
Three models of the LF-74 are available to satisfy
many customer set-ups:
• The base model is enhanced for GMAW welding
with consumables from bulk packages or when a
boom mounting is required.
• The bench model with heavy duty wire reel stand
targets operators performing GMAW or FCAW weld-
ing using consumables on spools.
• The high torque model features high ratio gearing
for feeding larger diameter FCAW or GMAW wires.
All models use a high performance motor-gear box
with an integrated tachometer.
OPERATION
General Functional Description
The LF-74 fulfills the need for an economical wire
feeder with a high performance wire drive. Functional
features included are those that offer the most value –
a WFS knob with a calibrated printed scale, cold-feed/
gas purge switch, trigger interlock switch and
tachometer motor control.
RECOMMENDED PROCESSES
•
GMAW
•
FCAW
PROCESS LIMITATIONS
• The LF-74 is not recommended for GMAW-Pulse
Synergic, GTAW, GTAW-Pulse, CAG, SMAW
• The LF-74 is not compatible with push-pull equip-
ment.
• For the heavy duty bench models K2426-2 and
K2426-3, the maximum spool size = 60 lb. (27.2 kg).
REQUIRED EQUIPMENT
Lincoln's LF-74 is designed for use with the CV and
DC family of power sources. These include:
• CV-250
• CV-300
• CV-305
• CV-400
• CV-655
OTHER COMPATIBLE POWER SOURCES
• Ranger 250
• Ranger 305
• Commander 300
• Vantage 300
• Vantage 500
• Air Vantage 500
EQUIPMENT LIMITATIONS
• Maximum GMAW gun length = 25' (7.6m)
• Maximum FCAW gun length = 15' (4.6m)
• Maximum conduit length = 30' (9.1m)
• Maximum total control cable length = 100ft (31m)
• The LF-74 operates on 24-42VAC and not 115 VAC
• The K1733-1 and K1733-3 wire straighteners are
not compatible with the LF-74
• Gun bushings are required for welding guns that do
not have a Magnum (Tweco #2-#4 compatible) back
end.
• The LF-74 does not attach to K303 or K377 wire
reel stands.
LF-74
• DC-400
• DC-600
• DC-655
• Invertec V350
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