Lincoln Electric LF-72/74 service manual AA-18, Figure AA.12b

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AA-18		INSTALLATION		AA-18

ALUMINUM WIRE PREPARATIONS				FIGURE AA.13

		WARNING

ELECTRIC SHOCK can kill.

•Turn the input power OFF at the dis- connect switch before working on this equipment.

•Do not touch electrically hot parts.

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Welding with aluminum filler wires requires extra care. Aluminum wire is softer and not as stiff as steel wires, it is important to keep aluminum wire free of dirt and scratches. Limit gun length to 10 Ft.(3.0 m) for best results and use a spool cover if feeding from a spool.

To prevent scratching of the aluminum wire, remove the ball bearings from the ball housing as follows.

Tools required: (See Figure AA.12b)

•9/64" Hex key wrench

1.Turn off power at the welding power source.

2.Remove the o-ring holding the ball bushing assem- bly to the back of the wire feeder. Remove the ball bushing assembly.

4.Place the ball bushing housing into the wire feeder case and secure with the “O” ring.

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FIGURE AA.12b

"O" RING

3.Remove the three socket head cap screws from the ball bushing assembly. Caution: as the screws are being loosened, the balls may fall free from the assembly. Remove the balls and the steel washer.

LF-72/74

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Contents LF-72/74 Safety Electric Shock can kill Welding Sparks can cause fire or explosion IiiPrécautions DE Sûreté Sûreté Pour Soudage a L’ArcMaster Table of Contents for ALL Sections Table of Contents Installation SectionSection A-1 Installation Amp Rating Duty CycleSafety Precaution LocationMounting Bench Mount Swivel MountBoom Mount SuspendedWeld Cable Sizes Coaxial Weld Cables Weld Cable ConnectionINSTALLATIONA-7 Analog Control CableControl Cable Connections Miller Power Source Lincoln Wire Feeder Analog Miller Control Cable Adapter K2335-1Pin Function Wire Drive Systems Welding GUN/WIRE Feeder Trigger ConnectorRemote Sense Lead Specifications High Frequency ProtectionWelding GUNS, Torches and ACCES- Sories Magnum GUN and Cable AssembliesProcedure for Changing Drive and Idle Roll Sets Wire Drive ConfigurationRolls.FIGURE A.4 Pressure ARM Adjustment Gun Receiver For use With BushingSet the pressure arm as follows See Figure A.6 Wire Reel Loading Weld Wire Routing Figure A.9Shielding GAS Connection Installing Electrode To install Lincoln conduit See Figure A.10bConduit Kits For Codes 11209, 11210, 11211 and aboveAluminum Wire Preparations Figure A.12bINSTALLATIONA-18 Base Model Bench Model Standard Duty Bench Model Heavy DutyTypical System Configurations CableLF-72/74 Operation Section Section B-1Operation GAS Input Work ConnectionCommon Welding Abbreviations Product DescriptionRecommended Processes Front Panel Controls and Connections Figure B.1 Case Front Controls DescriptionBurnback and Postflow Timer KIT Cold FEED/GAS Purge SwitchStep Trigger Interlock Switch Remote Voltage Control KITWire Feed Speed Knob Trigger Connector 5-PIN AmphenolGUN Receiver Bushing K1500-2 Trigger InterlockAccessories Section Section C-1Accessories Optional KitsLF-72s Accessories Key LF-72/74 Maintenance Section Section D-1Maintenance MaintenanceCalibration Specification Routine MaintenanceFigure D.1 Figure D.3 Major Component Location Section AA-1 Section AAWFS Range Wire Sizes AA-2Model AA-3 Figure AA.1AA-4 AA-5 AA-6 Coaxial Weld CableINSTALLATIONAA-7 AA-7K1797-xx AA-8 Drive Roll Kits Steel or Cored Wires AA-9AA-10 Figure AA.3AA-11 Changing the Gun Receiver BushingLation or changing drive rolls and/or GuidesAssembly of Drive Rolls and Wire Guides AA-12AA-13 Set the pressure arm as follows See Figure AA.8AA-14 AA-15 Loading 16 to 44 lb .3 20kg Spools See figure AA.8AA-16 Figure AA.11AA-17 Figure AA.12aAA-18 Figure AA.12bAA-19 AA-20INSTALLATIONAA-20 Common Equipment SET-UPSFigure AA.15 High Volume Production AA-21Figure AA.16 Portable Welding AA-22Section BB-1 Section BBBB-2 Fcaw Innershield or OutershieldRequired Equipment BB-3BB-4 Figure BB.1 Case Front Controls DescriptionBB-5 K2426-1 and K2426-2 modelsK2426-3 model Switch BB-6Section CC-1 CC-2 CC-3 CC-4 CC-5 CC-6 Section DD-1 Section DDTo verify the wire feed speed Nal wiringWhen inching with gun trigger, electrode WFS knob setting Could remain energized Several secondsMAINTENANCEDD-3 DD-3Figure DD.3 Major Component Location DD-4Theory of Operation Section Section E-1Theory of Operation Return to SectionControl Board LF-72/74 Troubleshooting & Repair Section Section F-1Troubleshooting & Repair HOW to USE Troubleshooting GuidePC Board Troubleshooting Procedures Function Problems Function Problems Troubleshooting & Repair Drive Motor and Tach Feedback Test Test DescriptionTest Procedure Troubleshooting and Repair GAS Solenoid TestTest Procedure Figure F.3 Leads 552, 552BDiode Bridge Test 552B + 552A Wire Speed Potentiometer Test Wire Speed Potentiometer Test 14F-14PC Board Removal and Replacement Control PC Board Removal and Replacement Procedure Removal Procedure Replacement ProcedureTroubleshooting and Repair Wire Drive Motor and Gear BOX Removal and Replacement ProcedureProcedure Replacement Procedures SET UP Operation VerificationLF-72/74 Electrical Diagrams Section Section G-1Electrical Diagrams LF-72/74Timer 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