Lincoln Electric LF-72/74 service manual Calibration Specification, Routine Maintenance

Page 40

Section TOC

Master TOC

D-2

MAINTENANCE

D-2

 

 

 

MAINTENANCE

CALIBRATION SPECIFICATION

 

WARNING

 

Safety Precautions

 

ELECTRIC SHOCK can kill.

 

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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 sys- tem ground per the National Electrical Code or any applicable local codes.

•Only qualified personnel should perform mainte- nance work.

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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.

•Do not touch electrically live parts.

•When inching with the gun trigger, 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.

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Calibration of the LF-72 may be required when the p.c. board, potentiometer or motor is replaced or serviced. Calibration matches the scale on the name plate to the actual wire feed speed.

To verify if calibration is necessary:

1.Turn off power to the LF-72.

2.Assemble .045 drive rolls, inner guide and the outer guide into the drive. Remove the gun from the wire feeder if assembled.

3.Load .045 wire into the drive. Cut the wire flush with the end of the gun bushing.

4.Set the WFS knob to 300 ipm.

5.Using the COLD FEED switch, feed wire for 10 seconds.

6.Cut the wire flush with the end of the gun bushing. Measure the length of the wire. If the wire mea- sures 50 ± 2.5 inches then calibration is not required.

Tools required:

5/16" nut driver

3/4" open end wrench WFS meter or RPM meter

Shorting plug. The shorting plug shorts pins 1

&5 of connector J2 on the p.c. board. J2 is a

6 pin molex connector.

To calibrate the LF-72:

1.Turn off power to the LF-72.

2.Disconnect the electrode lead from the feedplate and from the welding power source.

3.Remove the 5 screws securing the wraparound. (The door is not shown for clarity. “See Figure D.1”)

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 Installation Section Table of ContentsSection A-1 Installation Amp Rating Duty CycleLocation Safety PrecautionMounting Bench Mount Swivel MountBoom Mount SuspendedWeld Cable Sizes Coaxial Weld Cables Weld Cable ConnectionAnalog Control Cable INSTALLATIONA-7Control Cable Connections Analog Miller Control Cable Adapter K2335-1 Miller Power Source Lincoln Wire FeederPin 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 AssembliesWire Drive Configuration Procedure for Changing Drive and Idle Roll SetsRolls.FIGURE A.4 Gun Receiver For use With Bushing Pressure ARM AdjustmentSet 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 ConnectionProduct Description Common Welding AbbreviationsRecommended 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 AAAA-2 WFS Range Wire SizesModel AA-3 Figure AA.1AA-4 AA-5 AA-6 Coaxial Weld CableAA-7 INSTALLATIONAA-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 DescriptionK2426-1 and K2426-2 models BB-5K2426-3 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
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