Lincoln Electric LF-72/74 service manual Common Welding Abbreviations, Product Description

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B-3

OPERATION

B-3

 

 

 

 

PROCESS LIMITATIONS

 

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COMMON WELDING ABBREVIATIONS

WFS

• Wire Feed Speed

CV

•Constant Voltage

GMAW (MIG)

• Gas Metal Arc Welding

FCAW (Cable Innershield or Outershield)

•Flux Core Arc Welding

PRODUCT DESCRIPTION

•Rated for up to 1/16(1.6 mm) solid electrode and 5/64 (2.0 mm) cored electrode.

•The maximum WFS is 800 in/min (20.3 M/min).

•The LF-72 is not recommended for GMAW-Pulse (synergic), GTAW, GTAW-Pulse, SAW, CAG, SMAW.

•Do not use push-pull equipment with the LF-72.

•For K2327-2 Bench model, std. duty: Maximum spool size = 44 lb. (20 kg); 12 inch (300mm) diame- ter; 4 inch (100mm)

•For K2327-3 Bench model, heavy duty: Maximum spool size = 60 lb. (27.2 kg)

REQUIRED EQUIPMENT

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General Physical Description

The LF-72 is optimized for .035 through .045 (0.9mm through 1.2mm) GMAW welding. The powerful 2 roll drive, heavy duty enclosure and wire reel stand com- bine to make an easy to install, easy to use wire feed- er for everyday welding. Powering the wire drive is a high performance 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. Also under the door is a convenient storage tray for contact tips and tools.

Three packages are available. The basic unit consists of the wire drive box housing. The standard duty bench model targets users of 12" (305 mm)diameter spools. The heavy duty bench model satisfies the needs of customers using 60 lb (27.2 kg) spools.

General Functional Description

•The LF-72 is a highly versatile and economical choice of industrial feeders. Easy to use features are a cali- brated WFS knob, cold-feed/ gas purge switch and trigger interlock.

•Several kits are available to expand the LF-72’s weld- ing capability. The timer kit allows adjustment of burn- back and postflow times. The remote voltage control kit includes a 0 to 10 dial for setting the welding volt- age at the wire feeder. The swivel kit mounts to the lift bail of a power source and lets the feeder freely rotate so the gun cable stays straight.

Lincoln’s LF-72 is designed for use with the CV and DC family of power sources. These include:

• CV-305

• DC-400

• CV-400

• DC-600

•CV-655 • Invertec™ V350

•Invertec™ V450

EQUIPMENT LIMITATIONS

•Maximum gun length =25 ft. (7.6m)

•Maximum conduit length = 30 ft. (9.1m)

•Maximum total control cable length = 100ft (31m)

•The LF-72 operates on 42VAC and not 115 VAC

•The K1733-1 wire straightener may not be used with the LF-72

•Gun bushings are required for welding guns that do not have a Magnum (Tweco #2-#4 compatible) back end.

•The LF-72 does not attach to K303 wire reel stands.

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RECOMMENDED PROCESSES

•GMAW .023-1/16 (0.6 - 1.6 mm) steel electrodes.

•FCAW .035 -5/64 (0.9 - 2.0mm) cored electrodes

LF-72/74

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Contents LF-72/74 Safety Electric Shock can kill Iii Welding Sparks can cause fire or explosionSûreté Pour Soudage a L’Arc Précautions DE SûretéMaster Table of Contents for ALL Sections Section A-1 Table of ContentsInstallation Section Amp Rating Duty Cycle InstallationMounting Safety PrecautionLocation Swivel Mount Bench MountBoom Mount SuspendedWeld Cable Sizes Weld Cable Connection Coaxial Weld CablesControl Cable Connections INSTALLATIONA-7Analog Control Cable Pin Function Miller Power Source Lincoln Wire FeederAnalog Miller Control Cable Adapter K2335-1 Welding GUN/WIRE Feeder Trigger Connector Wire Drive SystemsRemote Sense Lead Specifications High Frequency ProtectionMagnum GUN and Cable Assemblies Welding GUNS, Torches and ACCES- SoriesRolls.FIGURE A.4 Procedure for Changing Drive and Idle Roll SetsWire Drive Configuration Set the pressure arm as follows See Figure A.6 Pressure ARM AdjustmentGun Receiver For use With Bushing Wire Reel Loading Figure A.9 Weld Wire RoutingShielding GAS Connection To install Lincoln conduit See Figure A.10b Installing ElectrodeConduit Kits For Codes 11209, 11210, 11211 and aboveFigure A.12b Aluminum Wire PreparationsBase Model Bench Model Standard Duty Bench Model Heavy Duty INSTALLATIONA-18Cable Typical System Configurations LF-72/74 Section B-1 Operation SectionGAS Input Work Connection OperationRecommended Processes Common Welding AbbreviationsProduct Description Figure B.1 Case Front Controls Description Front Panel Controls and ConnectionsCold FEED/GAS Purge Switch Burnback and Postflow Timer KITStep Trigger Interlock Switch Remote Voltage Control KITTrigger Connector 5-PIN Amphenol Wire Feed Speed KnobGUN Receiver Bushing K1500-2 Trigger InterlockSection C-1 Accessories SectionOptional Kits AccessoriesLF-72s Accessories Key LF-72/74 Section D-1 Maintenance SectionMaintenance MaintenanceCalibration Specification Routine MaintenanceFigure D.1 Figure D.3 Major Component Location Section AA Section AA-1Model WFS Range Wire SizesAA-2 Figure AA.1 AA-3AA-4 AA-5 Coaxial Weld Cable AA-6K1797-xx INSTALLATIONAA-7AA-7 AA-8 AA-9 Drive Roll Kits Steel or Cored WiresFigure AA.3 AA-10Changing the Gun Receiver Bushing AA-11Lation or changing drive rolls and/or GuidesAA-12 Assembly of Drive Rolls and Wire GuidesSet the pressure arm as follows See Figure AA.8 AA-13AA-14 Loading 16 to 44 lb .3 20kg Spools See figure AA.8 AA-15Figure AA.11 AA-16Figure AA.12a AA-17Figure AA.12b AA-18AA-19 Common Equipment SET-UPS AA-20INSTALLATIONAA-20AA-21 Figure AA.15 High Volume ProductionAA-22 Figure AA.16 Portable WeldingSection BB Section BB-1Fcaw Innershield or Outershield BB-2BB-3 Required EquipmentFigure BB.1 Case Front Controls Description BB-4K2426-3 model BB-5K2426-1 and K2426-2 models BB-6 SwitchSection CC-1 CC-2 CC-3 CC-4 CC-5 CC-6 Section DD Section DD-1Nal wiring To verify the wire feed speedWhen inching with gun trigger, electrode WFS knob setting Could remain energized Several secondsDD-3 MAINTENANCEDD-3DD-4 Figure DD.3 Major Component LocationSection E-1 Theory of Operation SectionReturn to Section Theory of OperationControl Board LF-72/74 Section F-1 Troubleshooting & Repair SectionHOW to USE Troubleshooting Guide Troubleshooting & RepairPC Board Troubleshooting Procedures Function Problems Function Problems Troubleshooting & Repair Test Description Drive Motor and Tach Feedback TestTest Procedure GAS Solenoid Test Troubleshooting and RepairFigure F.3 Leads 552, 552B Test ProcedureDiode Bridge Test 552B + 552A Wire Speed Potentiometer Test 14F-14 Wire Speed Potentiometer TestPC Board Removal and Replacement Removal Procedure Replacement Procedure Control PC Board Removal and Replacement ProcedureTroubleshooting and Repair Procedure Wire Drive Motor and Gear BOX Removal and ReplacementProcedure Replacement Procedures Operation Verification SET UPLF-72/74 Section G-1 Electrical Diagrams SectionLF-72/74 Electrical DiagramsTimer KIT Board Normal Speed Micro Internal panel Motor Connecter Summary High Torque Setting engages Schematic Common Analog Control PC Board G4559 Sheet Electrical Diagrams Electrical Diagrams PC Board Assembly Common Analog Control G4560-2E0
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