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Lincoln Electric LF-72/74 Welder User Manual

1. 510 4 bln D Cyc 3 Bin ojo VSENSE DRIVE ISENSE 24 pro 20 INPUT VOLTAGE 8 BRAKE ON 5900 5 0 Pozi exa COLO INCH SPEED CTRL 26 pojal 22 72 GAS PURGE SLOSENSE 27 x TACH SIGNAL irm rans SPODL GUN DETECT PEAK CUR LIM 15 pin i L SPOGL GUN DETECT _ 7 api piro 18 THERMOSTAT INDICATOR LIGHT gt DATA 16 pato GAS FLOW ENABLE gt causare gt mae SOLENOID DRIVE MOTOR SELECT XRES Return to Section TOC Return to Master TOC GENERAL INFORMATION a ELECTRICAL SYMBOLS PER E1637 HM CAPACITORS MFD 022 50V UNLESS OTHERWISE SPECIFIED RESISTORS Ohms 1 4W UNLESS OTHERWISE SPECIFIED LABELS gt SUPPLY VOLTAGE NET DIODES 1A400V UNLESS OTHERWISE SPECIFIED POWER SUPPLY SOURCE POINT 57 COMMON CONNECTION FRAME CONNECTION PROPRIETARY INFORMATION OWNED BY LINCOLN GLOBAL INC AND MAY NOT BE DUPLICATED COMMUNICATED PROPRIETARY amp CONFIDENTIAL Th Pisis Ub USED EU ANY BORSE WITHOUT THE EXPRESS WRITTEN PERMISSION LINCOLN GLOBAL AYORA
2. A 11 5 Wire Drive ConfIGUratiOni uiii A 11 A 12 Pressure Arm Adjustment 12 8 Wire Reel edt erre 13 8 Weld Wire Routing A 14 Sheilding Gas CONNECTIONS cepas rude pee Ca tee bee vare ee A 15 Installing Electrode Conduit Kits petitione ri reine tie A 16 Aluminum Wire A 17 Base Model Bench Model Standard Duty and Bench Model Heavy Duty A 18 Typical System A 19 8 5 LF 72 74 SINGLE DUAL LINCOLN B ii INSTALLATION A 2 TECHNICAL SPECIFICATIONS LF 72 Wire Feeder ojo 9 5 SPEC TYPE WIRE FEED SPEED RANGE 9 Wire Size ol9 LF 72 Speed Solid Cored K2327 1 8 K2327 4 Base Model 2327 2 Bench Model 50 800 IPM 023 1 16 in 035 5 64 in Standard Duty 1 27 20 3 m m 0 6 1 6 mm 0 9 2 0 mm K2327 3 Bench Mode Heavy Duty CONTROL BOX WIRE DRIVE AND COMPLETE UNITS SPEC TYPE INPUT POWER PHYSICAL SIZE Dimensions TEMPERATURE RATING and Current Height Width Depth Weight Operating Storage 43 Lbs K2327 1 LF 72 11 1 10 2 12 9 19 7 282 259 mm 328 mm Base Model 26 5 Lbs 12 0 Kg Dimensions A Height Width Depth W
3. e PK 4 ut cL ET E t 47 60 No 15V MOTOR SELECT 2 5 1 3404 45V 13482 gu 29 MOTOR p oh 1 a mies TRIGGR INTRLK_EN p t IG T ri L 5 VSENSE 21 T Sov 1 E Ez 1 013 Y AGS A t 1 2 gas ON OFF lt 340 sla 1 dE T 6900 mr RIOT ti aah TAR REUS tt t 65591 1 T NES m R68 3 18 f 1 x 100 sw COLD ZAK 70 ok p ee CIE ig dog E Vi H EA T H 8 24 E 019 il ____ 1 GAS PURGE es m 310 Ll tk OK Tu T gt 2058 GAS FLOW ENABLE 3 100 A 20560 ONLY 024 BURNBACK ooe 1 p UE 5 E T a Bi 1 158 Vi FIERD DC hook 7 a POWER SOURCE d ENG 95 OUTPUT CONTROL 12 BS 2559 gt a T 2 2 5 Sw power sonte Vi OUTPUT ENABLE mv 1 d div MAIN gean MOTOR le onc 4 Rea C cQ DE SP gt WR T
4. TO ELECTRONIC COMPONENT DATABASE FOR SPECIFICATIONS ON ITEMS BELOW C12 C13 C14 C15 C16 16 925020 278 5 0 1 50 20 80 250 50805 C27 C28 C29 C35 C36 B 2 C31 C34 v C3 65 CAPACITOR ALEL 220 25V 20 LOW ESR C6 5 5626 138MT CAPACTTOR SMD CERAMIC 5007 COG S0805 co CU 921 C26 C32 C30 pg BEOMASMT SND SWS N 5 02 CS 2504635 ZENER DIODE SMD 0 5W 18V 5580013 1000 _ 11200245 7 TENER DIODE 18 5 TNATAGA 02 D3 D7 D D9 Dio 6 s2504o 115MT DIODE SMD 1A 600V S403A ULTRA FASTRECOVERY 1 S25040 25MT DIODESMDAUV DOZI4BA AC NH Olio D6 031 Qe FIFE DIZ DES 6 2004055 MT DIODE SMD DUALO2DDA els 6 14 016 215 519 520 024 Dor 5 S2504645MT DIODE SMD OUAL O 200A 70V UFR O O O d olo 28 029 030 5 9 2 3 2 1112 8 COMMON ANALOG WIREDRIVE 69 z 1 515000 209 IOPTOCOUPLER SMD SSR FORM 1A 0 08A 350V pee S20 12ST TRANSISTOR SMD NMP DPAK 2007155 cle Q2 015 Bin NAS oz 08 09 5 E 010 617 074 s 625651 48MT TRANSISTOR SMD NMF SOT 23 0 7O02LTSS R22 R64 R83 R85 R86 12 825
5. D 2 t D 2 Calibration Specification 2 aaae annaa D 2 D 3 Major Component D 4 Return to Master TOC 2 D 2 8 5 Return to Master TOC LF 72 74 SINGLE DUAL LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC 515 0 9 2 2 SZ Return to Section TOC Return to Master TOC Return to Master TOC MAINTENANCE Safety Precautions A WARNING ELECTRIC SHOCK can kill 0 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 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
6. Return to Section TOC Return to Master TOC Return to Master TOC AA 6 COAXIAL WELD CABLES Coaxial welding cables are specially designed welding cables for pulse welding welding Coaxial weld cables feature low inductance allowing fast changes in the weld current Regular cables have a higher inductance which may distort the pulse wave shape Inductance becomes more severe as the weld cables become longer Coaxial weld cables are recommended for all pulse welding especially when the total weld cable length electrode cable work cable exceeds 50 feet 7 6m Coaxial Weld Cable Power Source Work Electrode Coaxial Weld Cable INSTALLATION AA 6 A coaxial weld cable is constructed by 8 small leads wrapped around one large lead The large inner lead connects to the electrode stud on the power source and the electrode connection on the wire feeder The small leads combine together to form the work lead one end attached to the power source and the other end to the work piece See Coaxial weld Cable below WELD CABLE CONNECTION Connect a work lead of sufficient size between the proper output stud on the power source and the work Be sure the connection to the work makes tight metal to metal electrical contact Poor work lead connections can result in poor welding performance Wire Feeder Electrode LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC
7. 8 e Return to Section TOC Return to Master TOC 2 D 8 3 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 A WARNING ELECTRIC SHOCK can kill 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 To calibrate the wire feed speed Tools required 5 16 nut driver 3 4 open end wrench WFS meter or RPM meter Shorting plug The shorting plug shorts pins 1 and 5 of connector J2 on the p c board J2 is a 6 pin molex 1 Turn off power to the LF 74 and welding power Source 2 Disconnect the electrode lead from the feed plate and from the welding power source 3 Remove the wraparound from the LF 74 See 4 Turn on power to the LF 74
8. Return to Section TOC Return to Master TOC _ CONTROL wal NORMAL SPEED Ney ee Sc L p 21 P delis NE Pll B HIGH TORQUE BAFFLE b B MOUNTED MEUS RECTIFIER DIODE BRIDGE Return to Section TOC Return to Master TOC 14PIN AMPHENOL CONNECTOR TO POWER SOURCE NOTES 587 608 iw 558 601 589 e 5 6 915 2 8 5 5 45 ojo OF BOARD NB CAMTY NUMBERING SEQUENCE AS VIEWED FROM LEAD SIDE OF 11 12 13 14 15 16 245 9 1011 12 13 14 15 16 NE TOSA ican CRANES 1117177 11111111111111 iC ci rH CONNECTIONSIDE OF SWITCH PIN NEAREST THE FLAT EDGE OF LEDLENS ALIGNS WTH WHITE LEAD OF LEDSOCKET NE PLACE P11 INAPPROPRIATE POSITION FORSPEED OR TORQUE CONNECTIONSHOANIS FOR NORMAL SPEED NOTE NORMAL SPEED NOT AVAILABLE ON HGH TORQUE MOLEL HGHTORQUE NOT AVAILABLE ON NORMAL SPEED MODEL E 559 515 CAVITY NUMBERING SEQUENCE AS VIEWED FROMCOMPCNENT SIDE ji 7 Return to Section TOC Return to Master TOC NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual The wiring diagram specific to your code is pasted inside one of the enclosure panels of your machine LINCOLN LF 72 74 e ELECTRICAL DIAGRAMS SCHEMATIC ENTIRE MACHINE
9. Section F Electrical Diagrams Section G Parts 2 2 4 446 P501 Series LF 72 P518 Series LF 74 LF 72 74 LINCOLN Section A 1 TABLE OF CONTENTS Section A 1 INSTALLATION SECTION 3 gt Installation EINER EITHER Section A 5 Technical A 2 Safety Precautions A 3 MOC ATION ee A 3 eire siete A 3 denm TR A 4 SWIVEL ME E A 4 T BOOM MOUN ERES A 4 Suspended ossi LI MU UE A 4 5 5 Wald A 6 5 Weald Cable uicit pit repe A 6 8 Analog Control Cable A 7 Analog Miller Control Cable A 8 Welding Gun Wire Feeder Trigger A 9 High Frequency Protection A 9 Remote Sense Lead A 9 Wire A 9 T Welding Guns Torches and A 10 Procedure for Changing Drive and Idle Roll Sets
10. AA 8 Welding Gun Wire Feeder Trigger Connector AA 9 High Frequency AA 9 Remote Sense Lead Specifications AA 9 LATCH TEE AA 9 Welding Guns Torches and Accessories AA 10 Wire Drive Configuration reir ten 11 5 Assembly of Drive Rolls and Wire Guides AA 12 Pressure Arm Adjustment electi AA 13 Shielding Gas Connec ON eso esed ia SEL ep eo Roin AA 14 Wire Reel Loading AA 15 AE MEE 16 Installing Electrode Conduit nct rn rib AA 17 Aluminum Wire Preparations AA 18 Base Model Bench Model and Extra Torque Bench Model AA 19 Common Equipment 20 i High Volurmie ProductlOni sucio AA 21 Portable CR UR MR AA 22 8 5 LF 72 74 LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 I S 5 9 8 c ra Return to Section TOC Return to Master TOC 2 9 o
11. 901 Je1Se N 01 201 ISEW 01 DOL uonoeg DOL uonoeg DOL uunjeH 901 Section B 1 TABLE OF CONTENTS Section B 1 OPERATION SECTION 3 gt RELIER NEL Section B 2 5 Bare Precaution Stereos E sidebar B 2 Graphic SYMDOIS B 2 Common Weldirig ADDrevIatiOris occ ia editio ed kde ame B 3 Product Descriptores ee tti DR REI FORMEN D ILE B 3 Recommended Processes and Required B 3 Front Panel Controls and Connections nnne B 4 T 1 Remote Voltage Control Kit B 5 2 Burnback and Postflow Timer Optional B 5 5 3 Thermal LED Motor Overload B 5 gt 4 Cold Fead Gas Purge SW Ch metodi tut e itn B 5 8 5 2 Step Trigger Interlock 44 444400 B 5 B 6 6 Wire Feed Speed B 6 7 un Receiver BUSING to a B 6 8 Trigger Connector 5 Pin B 6 i 2 2 E tc i
12. CWIRE DRIVE UNIT GUN HANDLE GUNTUBE N GUNNOZZLE GUN AND CABLE EI Se x i 74 GUN TRIGGE 7 CONNECTOR END 466 10 LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC ojo O 515 0 2 2 SZ Return to Section TOC Return to Master TOC Return to Master TOC AA 11 WIRE DRIVE CONFIGURATION See Figure AA 5 Changing the Gun Receiver Bushing WARNING ELECTRIC SHOCK can kill s e Turn the input power OFF at the welding power source before instal lation or changing drive rolls and or guides Do not touch electrically live parts When inching with the gun trigger electrode and drive mechanism are hot to work and ground and could remain energized several seconds after the gun trigger is released Only qualified personnel should perform mainte nance work Tools required 1 4 hex key wrench Note Some gun bushings do not require the use of the thumb screw Turn power off at the welding power source Remove the welding wire from the wire drive Remove the thumb screw from the wire drive Remove the welding gun from the wire drive Loosen the socket head cap screw that holds the connector bar against the gun bushing Important Do not attempt to completely r
13. Return to Section TOC Return to Master TOC AA 12 ASSEMBLY OF DRIVE ROLLS AND WIRE GUIDES WARNING ELECTRIC SHOCK can kill Turn the input power OFF at the welding power source before instal lation or changing drive rolls and or guides Do not touch electrically live parts When inching with the gun trigger electrode and drive mechanism are hot to work and ground and could remain energized several seconds after the gun trigger is released Only qualified personnel should perform mainte nance work To remove drive rolls and wire guides See Figure AA 6 1 Turn power off at the welding power source 2 Remove the outer wire guide 3 Rotate 4 triangular rings to the unlocked position 4 Open the pressure arms 5 Remove the drive rolls and inner wire guide FIGURE AA 6 P 2 PRESSURE ARMS Y ROTATE DOWN A 4 TRIANGULAR RINGS IN UNLOCKED POSITION OUTER WIRE GUIDE INSTALLATION AA 12 To install drive rolls and wire guides See Figure AA 7 and AA 7a 1 Turn off power at the welding power source 2 Open pressure arms 3 Assemble the inner wire guide 4 Slide the drive rolls onto the drive hubs See figure AA 7 5 Close the pressure arms 6 Rotate 4 triangular rings to the locked position See figure AA 7a 7 Assemble the outer wire guide 8 Adjust the pressure arms to the recommended set ting FIGURE AA 7 y DRIVE HUBS PRESSURE ARMS IN O
14. _ ds a So KA iw iW TRIGGER INPUTS em COM lt a E 876 RIJ RB Jt iw 19 y x 4 600 OHMS 9 5 nR B gt S Vm 4 E 57 Vet A 8 lye lo 121 12 r 1x L 4716W E
15. INFORMATION rerenence EQUIPMENT WIREDRIVE CONTROL 03 OF 03 03 OF 03 DRAWN SUBJECT SCHEMATIC CONTROL PCB RR REVISION DO NOT eem Amt 050 6 4559 2 0 1 Mie 4 24 2006 Return to Section Return to Master TOC NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual LINCOLN LF 72 74 G 13 ELECTRICAL DIAGRAMS G 13 PC BOARD ASSEMBLY COMMON ANALOG CONTROL G4560 2E0 Olio Z 09SPD ENGINEERING CONTROLLED CHANGE DETAIL CHANGED FROM A BUY TO A MAKE OR BUY AND ADDED MAKE INFO PARTNUMBER DESCRIPTION _____________ AES MANUFACTURER Yes ADDED RUY SPEC NUMBER ANU 4 LATER BOARD BEANIE PANEL 1 o o 2 B Ola 1139 E2527 EPOXYENCAPSULATNGRESIN N D ELECTRICAL INSULATING COMPOUND
16. 2 818 cic SZ Return to Section TOC Return to Master TOC LF 72 74 LINCOLN 5 F 22 2 E RE DOL 01 DOL Je1se N 901 Je1Se N 01 201 ISEW 01 F 22 DOL uonoeg DOL uonoeg DOL uunjeH 901 Section G 1 TABLE OF CONTENTS Section G 1 ELECTRICAL DIAGRAMS SECTION 3 gt Electrical 5 Section Wiring Diagram Entire Machine Code 11075 11076 11077 112146 LF 72 G 2 Wiring Diagram Entire Machine Code 11209 11210 11211 11227 L12146 1 LF 72 G 3 Wiring Diagram Entire Machine Code 11290 11291 11292 11293 L12146 2 LF 72 G 4 Wiring Diagram Entire Machine Code 11195 11196 11197 L12484 74 G 5 Schematic Entire Machine Code 11075 11076 11077 G4617 LF 72 G 6 Schematic Entire Machine Code 11209 11210 11211 11227 G4617 1 LF 72 G 7 Schematic Entire Machine Code 11290 11291 11292 11293 04617 2 LF 7
17. 2 D 2 8 5 Return to Master TOC Section E 1 TABLE OF CONTENTS Section E 1 THEORY OF OPERATION SECTION Theory of OpefaltlOn x daas nua ona Ee anne Section E General RR EN RE Sue E 2 Input Receptacle Control Board and Operator E 2 Drive Motor Tach Feedback and Gas E 3 FIGURE E 1 LF 72 74 BLOCK LOGIC DIAGRAM GAS SOLENOID 3 75 AMP OVERLOAD PROTECTION OPTIONAL OPTIONAL BURNBACK REMOTE RECEPTACLE TIMER VOLTAGE CONTROL To Gun Trigger 14 PIN INPUT CABLE gt RECEPTACLE CONTROL BOARD CAS PURGE 24 42 VAC TRIGGER INTERLOCK 2 STEP WIRE FEED SPEED POT LF 72 74 SINGLE DUAL LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC O10 515 0 9 nl 2 SZ Return to Section TOC Return to Master TOC Return to Master TOC zin THEORY OF OPERATION Ee FIGURE E 2 GENERAL DESCRIPTION amp INPUT RECEPTACLE CONTROL BOARD AND OPERATOR CONTROLS GAS SOLENOID 3 75 AMP OVERLOAD PROTECTION OPTIONAL BURNBACK TIMER 14 PIN INPUT CABLE gt RECEPTACLE 24 4
18. la o N fa A ul E 9 a u lt Q S o OE 2 I 5 gt gt W tn 4 DOL 01 201 Je1se N 201 Je1Se N 01 201 ISEW 01 DOL uonoeg DOL uonoeg DOL 901 uunjeH Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 8 Return to Section TOC Return to Master TOC 2 9 o gt gt 8 INSTALLATION TYPICAL SYSTEM CONFIGURATIONS The LF 72 is capable of welding with many different welding processes These processes may require reconfig uring the LF 72 with other products that may or may not be included with the model you purchased Use the Table 1 below to identify the basic items which are included in the LF 72 to utilize the various Welding Processes that the machine is capable of controlling TABLE 1 Feeder K2327 1 Base Model Standard Duty 15 Magnum 400 LF 72 035 045 0 9 1 2 mm K2327 3 Bench Model Heavy Duty Wire Reel Stand Drive Roll Kit CONTROL CABLE Standard duty up to 44 Ib 20 kg spools 035 045 combo 0 9 1 2 mm Heavy Duty up to 60 Ib 27 2 kg coils LF 72 74 LINCOLN 5 A 20 NOTES LF 72 74 LINCOLN A 20 DOL 01 DOL Je1se N
19. A K468 spindle adapter is required for loading 2 wide spools on 2 51mm spindles Use a K468 1 spindle adapter for loading 2 1 2 64mm wide spools See figure A 7 and figure A 8 1 Squeeze the release bar on the retaining collar and remove it from the spindle 2 Place the spindle adapter on the spindle aligning the spindle brake pin with the hole in the adapter 3 Place the spool on the spindle and align the adapter brake tab with one of the holes in the back side of the spool An indicator mark on the end of the spin dle shows the orientation of the brake tab Be cer tain the wire feeds off of the spool in the proper direction 4 Re install the retaining collar Make sure that the release bar snaps out and that the retaining collar fully engages the groove on the spindle FIGURE A 7 Adapter Spindle Placement The wire reel stand provides two mounting locations for the spindle Each mounting location consists of a tube in the center of the mast and locating slots Loading 16 to 44 Ib 7 3 20kg Spools See figure A 8 1 Squeeze the release bar on the retaining collar and remove it from the spindle 2 Place the spool on the spindle aligning the spindle brake pin with one of the holes in the back side of the spool An indicator mark on the end of the spin dle shows the orientation of the brake holding pin Be certain the wire feeds off of the spool in the prop er direction INSTALLATION A 13 3
20. 045 0 9 1 2mm 040 1 0mm Drive Roll Kits Cored Wires Includes 2 Knurled drive rolls and an inner wire guide KP1697 035C KP1697 045C KP1697 052C KP1697 1 16C KP1697 068 KP1697 5 64C 030 035 0 8 0 9mm 040 045 1 0 1 2mm 052 1 4mm 1 16 1 6mm 068 072 1 7 1 8mm 5 64 2 0mm Drive Roll Kits Aluminum Wire Includes 2 polished U groove drive rolls outer wire guide and an inner wire guide KP1695 035A KP1695 040A KP1695 3 64A KP1695 1 16A 035 0 9 mm 040 1 0mm 3 64 1 2mm 1 16 1 6mm DRIVE ROLLS INNER WIRE GUIDE LF 72 74 LINCOLN 5 INSTALLATION fie WELDING GUNS TORCHES AND ACCES 3 Fully insert the gun cable connector end into the SORIES gun receiver bushing and gently tighten the thumb screw as show in Figure A 3 below GUN RECEIVER BUSHING The LF 72 wire feeder comes with a K1500 2 gun receiver bushing 4 Connect the gun trigger connector to the trigger receptacle Make sure that the key ways are aligned and insert MAGNUM GUN AND CABLE ASSEMBLIES The LF 72 wire feeder model will accept a number of optional gun and cable assemblies An example of installing the Gun and Cable is shown in Figure A 3 with a 15 ft 4 6m long Magnum 400 gun and cable 8 2 8 Return to Master TOC 1 Turn off power at the welding power source 2 Unscrew Thumb screw on Wire Drive Unit until tip of screw no longer protr
21. 2 2 5 LF 72 74 SINGLE DUAL LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 515 0 2 218 SZ a Return to Section TOC Return to Master TOC SAFETY PRECAUTIONS Read this entire section of operating instructions before operating the machine A WARNING ELECTRIC SHOCK can kill e Unless using cold feed feature when feeding with the gun trigger the electrode and drive mechanism are always electrically energized and could remain energized several sec onds after welding ceases Do not touch electrically live parts or electrodes with your skin or wet clothing e Insulate yourself from the work and ground e Always wear dry insulating gloves ONLY QUALIFIED PERSONS SHOULD INSTALL USE OR SERVICE THIS EQUIPMENT READ AND FOLLOW THE MANUFACTURER S INSTRUC TIONS EMPLOYER S SAFETY PRACTICES AND MATERIAL SAFETY DATA SHEETS MSDS FOR CONSUMABLES READ THIS WARNING PROTECT YOURSELF amp OTHERS FUMES AND GASES can be dangerous 9 Keep your head out of fumes gt 0 Use ventilation or exhaust at the arc or both to keep fumes and gases from your breathing zone and gener al area WELDING SPARKS can cause fire or explosion Do not weld near flammable material Do not weld on containers which have held flam mable material ARC
22. 5 CC 2 CC 5 Return to Master TOC Return to Master TOC 2 D 2 8 5 Return to Master TOC POWER FEED 10M SINGLE DUAL LINCOLN 5 ACCESSORIES di OPTIONAL KITS Includes 10k potentiometer K2329 1 Remote Voltage Control Kit harness knob and decal with a 0 10 scale and mounting hardware Includes Panel and harness K2330 1 Timer Kit for adjusting burnback and postflow times Includes Wire Reel Stand for K2328 1 Standard Duty Wire Reel Stand up to 44 Ibs 20 kg spools Spindle and mounting hard ware K2331 1 Lift Bail Kit Includes Insulated lift bail for use with K2328 1 and hardware K2332 1 Swivel Kit Includes Swivel adapter and for use with K2328 1 Standard mounting hardware for attach Duty Bench Models ing to a power source lift bale Includes Coaxial weld cable of length xx Ends of the K1796 xx Co Axial Power Cable weld cable have lug connec tions Use for Pulse or STT welding Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Includes Twist Mate to Lug 2 0 cable 14 1 2m long with K1803 1 Work and Feeder Cables Ground Clamp and Twist Package Mate to Lug 2 0 Cable 9 2 7m long K1840 xx Weld Power Cable Twist Mate to Includes Twist Mate to Lug Lug 1 0 cable of length xx Includes Twist Mate to Twist Mate 1 0 Cable for 25 7
23. WRAPAROUND SCREWS For Codes above 11290 use 18 18 Replace P2 from the harness into connector J2 19 Turn off power 20 Secure the wraparound to the LF 72 with 5 Screws FIGURE D 2 LF 72 74 SINGLE DUAL LINCOLN B D 4 LF 72 74 LINCOLN MAINTENANCE FIGURE D 3 MAJOR COMPONENT LOCATION 1 Center Assembly 2 Wire Drive Assembly D 4 3 Wire Reel Stand LF 72 4 Wire Reel Stand LF 74 DOL 0 201 Je1se N 201 Je1Se N 01 201 ISEW 01 DOL uonoeg uunjeH DOL uonoeg 901 901 Section AA 1 TABLE OF CONTENTS Section AA 1 INSTALLATION SECTION 3 gt Section 5 Technical Specifications AA 2 Safety Precautions UR AA 3 Locatore megi rn EE E AA 3 AE ENG ue L AA 3 Bench ER AA 4 istam E AA 4 i BOOM etri ope EET AD AA 4 EI A EE 4 5 Wee ec rr NN AA 5 i Coaxial Weld Cables 6 5 Weld Cable Connections enr perse itia AA 6 5 Analog Control Cable Connections 7 Analog Miller Control Cable
24. essary PERIODIC MAINTENANCE Clean drive roll grooves Blow out or vacuum the inside of the feeder 2 MAINTENANCE Ese CALIBRATION SPECIFICATION A WARNING ELECTRIC SHOCK can kill 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 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 Th
25. 10 24 SCREWS 4 PLACES LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC FIR 5 0 9 218 cic 5 5 Return to Section TOC Return to Master TOC AA 4 BENCH MOUNT The LF 74 mounts in a variety of configurations As shipped from the factory the LF 74 is suitable for bench mounting or placing directly on top of the weld ing power source CV xxx and DC xxx product family only Bench Mount SWIVEL MOUNT The base model and heavy duty bench models may be mounted onto a swivel when a top a welding power source K1557 1 Swivel Kit and Bench Model with Heavy Duty Wire Reel Stand B K2332 1 Swivel Kit and Base Model LF 74 INSTALLATION AA 4 BOOM MOUNT When boom mounting remove the wire reel stand if assembled and secure the wire feeder directly to the desired surface SUSPENDED Only suspend the wire feeder by the handle lift bail of the portability kit K2426 1 shown with K2328 1Standard Duty Wire Reel Stand and K2331 1 Lift Bail A WARNING Alternative methods for hanging the wire feeder must not be used unless insulation is provided between the wire feeder enclosure and the hanging device LF 72 74 LINCOLN 5 AR INSTALLATION AAS SAFETY PRECAUTION ELECTRIC SHOCK can kill Only qualified personnel should perform this installation Turn off the input po
26. 76 TIA 7 Connector located behind case front P7 577 REMOTE CONTROL Located on VOLTAGE Case Front 576 Located on SPEED Case Fi 575 ise Front Connector located Gearbox ratio is 2 47 Mot ist CONTROL by sheet panel Motoris at electrode ome 0 VDC MIN WFS POTENTIOMETER Leads Pass through ES potential 2 5 VDC MIN WFS 515 ac Motor is located toroid 2 times e i behind 5758 563 3 glastic panel 575C 562 4 MOTOR 563 5758 5 551 7 550 lt 8 1 6V 100 IPM 30 6V 800 IPM Leads Pass through 12 toroid 3 times Located on Case Front Connector located on sheet panel Connector located behind sheet panel Leads Pass Motor Connecter Summary ised Pass used required for LF 74 through Ye toroid 2 times 38VDC at 42VAC input with control board disconnected 60VDC with control board connected LINCOLN 20 OHM OUTPUT ENABLED HIGH IMPEDANCE 0UTPUT DISABLED NOT USED NOT USED To Power Source Electrode Connection TRIGGER Located on INPUT Case Front m 554 TRIGGER CONNECTOR D JB Timer Board Summary Has potentiometers for burnback and postflow Preflow fixed at 30msec Burnback range is 0 to 0 25 sec Located Postflow range is 0 25 to 10 sec Caso Front Receives Gas Flow Enable signal Outputs 100 msec pulses to turn Gas Fl
27. Electrode LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Fg 515 0 2 2 SZ Return to Section TOC Return to Master TOC Return to Master TOC A 7 INSTALLATION ANALOG CONTROL CABLE CONTROL CABLE CONNECTIONS All control cables can be connected end to end to extend their length The control cable connecting the wire feeder to the power source is specially made for the welding envi ronment The wire feeder power requires overcurrent protection Connect the wire feeder only to power sources with overcurrent protection of no more than 15 amps POWER SOURCE WIRE FEEDER HY Reseved sd pex Output t ee Hum o UN trigger from feeder E Remote Voltage Control 77 al supply from feeder or remota F Remote Voltage Control Remote Voltage Control or emote supply from feeder or remote Reseved Reserve for Future Use 42 VAC Reserve for Future Use Unused Electrode voltage from feeder 67 Do not use more than 100 ft 30 5 m of control cable between the wire feeder and power source LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC ojo O 515 0 9 2 218 SZ Retur
28. LF 72 74 LINCOLN 5 21 INSTALLATION 21 FIGURE AA 15 HIGH VOLUME PRODUCTION Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC It Description em 1A LF 74 Base Model 1B K2426 1 035 045 0 9 1 2mm Drive Roll Kit 1C 10 3m Control Cable Pp ________ 1797 ______ Control Cable Extension Welding Gun Remote Voltage Control Kit Timer Kit ojo 515 o 9 2 218 SZ K1346 13 CV 400 K910 xx Ground Clamp K1842 xx Weld Power Cable Lug to Lug 1546 1 Incoming Bushing 035 1 16 0 9 1 6 mm Return to Section TOC Return to Master TOC LF 72 74 LINCOLN B 22 INSTALLATION 22 FIGURE 16 PORTABLE WELDING Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Item K Description Remote Voltage Control Kit K2426 3 LF 74 Extra Torque Bench Model with Heavy Duty Wire Reel Stand 10 3m Control Cable 085 045 0 9 1 2mm Drive ral K2331 1 1 ated Bail Ki K163 4 Wheeled Undercarriage Ki6342 Plastic Wire Cover for 50 6016 Wire Packages K586 1 Deluxe Gas Regulator K1803 1 inc J 3 16 See Power Source or Engine E Drive Literat re Welding Power Source 515 lo 9 2 g 9 SZ 2 3D K1797 xx ontrol Cable Exte
29. Re install the retaining collar Make sure that the release bar snaps out and that the retaining collar fully engages the groove on the spindle FIGURE A 8 Retaining Collar Loading 30 Ib 13 6 kg Readi Reels See Figure A 9 A K363 P Readi Reel adapter is required for loading these spools on 2 51mm spindles 1 Squeeze the release bar on the retaining collar and remove it from the spindle 2 Place the Readi Reel adapter on the spindle align ing the spindle brake pin with one of the holes in the adapter 3 Re install the retaining collar Make sure that the release bar snaps out and that the retaining collar fully engages the groove on the spindle 4 Rotate the spindle and adapter until the retaining spring is at the 12 o clock position 5 Position the Readi Reel so that electrode de reels in the proper direction 6 Set one of the Readi Reel inside cage wires on the slot in the retaining spring 7 Lower the Read Reel to depress the retaining spring and align the other inside cage wires with the grooves in the adapter 8 Slide the cage all way onto the adapter until the retaining spring pops up fully Removing a Readi Reel 1 To remove a Readi Reel from the an adapter depress the retaining spring with a thumb while pulling the Readi Reel cage from the adapter with both hands Do not remove the adapter from the spindle LF 72 74 LINCOLN B Return to Section TOC Return to Master TOC Return
30. Return to Section TOC Ojo O 515 0 9 2 2 SZ Return to Section TOC Return to Master TOC Return to Master TOC AA 7 INSTALLATION 2223 ANALOG CONTROL CABLE CONTROL CABLE CONNECTIONS K1797 xx The control cable connecting the wire feeder to the power source is specially made for the welding envi ronment The wire feeder power requires overcurrent protection Connect the wire feeder only to power sources with overcurrent protection of no more than 15 amps POWER SOURCE WIRE FEEDER LEAD A Reserved ea Reseved WE trigger from feeder HN EN trigger from feeder Remote Voltage Control supply from feeder or remote control signal from feeder or remote Remote Voltage Control C eei eor remote pply from feeder or remote Reseved Reserved 42 VAC iB Resewved Electrode voltage from feeder 67 Do not use more than 100 ft 30 5 m of control cable between the wire feeder and power source LF 72 74 LINCOLN 5 INSTALLATION ANALOG MILLER CONTROL CABLE ADAPTER K2335 1 This Lincoln Electric wire feeder may be mounted to a limited number of Miller Electric power sources The Miller power source must have the circular connector pin definition shown in the table below for proper oper ation of the wire feeder Be sure the Miller power source p
31. pj Ae vi SPEED u m aa 17 iW 02A 1 1 SET POINT L Pays 8 me 2 A We aov E mS 1 B a 1 46 DA dv eam spor EU 5 xw GN I1 9 2 Ag POT JS 1 3 3 WIRE 2 Wine x 73 K 6 100K 2 8 psv 019 4 275 RIZ TOK ps COM DAW 1769 ihv CONTACTOR 25 15 0 fs En 2 I ASSEMBLY 65815 1 INPUT VOLTAGE NE GENERAL INFORMATION AND SOLENOIDS A ELECTRICAL SYMBOLS PER E1697 CAPACITORS MFD 022 50 UNLESS OTHERWISE SPECIFIED 6560 1 1 1 t RESISTORS Ohma 1 4W UNLESS OTHERWISE SPECIFIED LABELS USE OF AN 64415 ONLY uh DIODES 1A400V UNLESS OTHERWISE SPECIFIED SUPPLY VOLTAGE NET RECTIFIER USE THE POWER SUPPLY SOURCE POINT D V COMMON CONNECTION d lage rorem TO 1 6 AND J1 2 LB com EARTH GROUND CONNECTION mu ae SW T THIS DOCUMENT CONTAINS PROPRIETARY INFORMATION OWNED BY LINCOLN GLOBAL INC AND MAY NOT BE DUPLICATED COMMUNICATED n2 Ss PROPRIETARY amp CONFIDENTIAL OTHER PARTIES OR USED FOR ANY PURPOSE WITHOUT THE EXPRESS WRITTEN PERMISSION OF LINCOLN G
32. 0 9 2 2 elt SZ Return to Section TOC Return to Master TOC Return to Master TOC C 3 ACCESSORIES OPTIONAL KITS Control Cable K1797 xx K2335 1 Adapter for Miller Power Sources K1520 1 42 Volt Transformer Kit Includes 14 pin to 14 pin wire feeder to power source control cable Includes Adapter control cable for connecting a Lincoln 42 VAC wire feeder to a 24 VAC Miller power source Includes One transformer kit for operating a 42 VAC wire feeder on a power source supplying only 115 VAC K1798 Adapter Cable for Control Cable to Includes Terminal Strip Power Sources K910 1 Ground Clamp Includes One 300 Amp K910 2 Ground Clamp Includes One 500 Amp Ground Clamp Gun Receiver Bushing for guns with K466 1 Lincoln gun connec tors Innershield and Subarc K1500 1 Gun Receiver Bushing for guns with K466 2 K466 10 Lincoln gun con standard on Magnum 200 300 400 guns LF 72 s and compatible with Tweco 4 K1500 2 Gun Receiver Bushing for guns K1500 3 with K613 7 Lincoln gun connec tors Magnum 550 guns and com patible with Tweco 5 Gun Receiver Bushing for gun with K466 3 Lincoln gun connec tors compatible with Miller guns 1500 5 Gun Receiver Bushing compatible with Oxo guns Includes Gun receiver bush ing set screw and hex key wrench Includes Gun receiver bush ing with hose ni
33. CODE 11075 11076 11077 G4617 LF 72 EJE 5 5 Tiu 9106 es 218 mI 5 5 8 ojo Return to Section TOC Return to Master TOC LINCOLN Control Board Summary until the trigger is released and then depressed again ARC CURRENT ARC VOLTAGE L 1 E SENSE Flow Off Timer Board Summary Case Front Has potentiometers for burnback postflow Preflow fixed at 30msec Burnback range is 0 to 0 25 sec range is 0 25 to 10 sec Receives Gas Flow Enable signal Outputs 100 msec pulses to turn Gas Flow 13 20 OHM OUTPUT ENABLED HIGH IMPEDANCE OUTPUT DISABLED 38VDC at 42VAC input with control board disconnected 60VDC with control board connected Has on board power supply Receives switch signals from Trigger Cold Feed Gas Purge Trigger Interlock Reads WFS potentiometer Communicates with optional timer kit to control burnback postflow Controls motor speed with PWM Turns Gas Solenoid on off Monitors motor current lights yellow thermal LED if over 4 amps for an extended time period LED remains lit for 30 60 seconds to allow motor to cool Does NOT support Run in atthis time Operates on 24 42 VAC Maximum WFS and or maximum pull force may be less when operating at 24 VAC D
34. Master TOC Return to Section TOC Return to Master TOC 8 8 e Return to Section TOC Return to Master TOC 2 9 o gt 2 14 SHIELDING GAS CONNECTION CYLINDER may explode if damaged 222 A gt Keep cylinder upright and chained to q support Keep cylinder away from areas where it may be damaged Never lift welder with cylinder attached Never allow welding electrode to touch cylinder Keep cylinder away from welding or other live electrical circuits BUILD UP OF SHIELDING GAS may harm health or kill Shut off shielding gas supply when not in use SEE AMERICAN NATIONAL STANDARD 2 49 1 SAFETY IN WELDING AND CUTTING PUB LISHED BY THE AMERICAN WELDING SOCIETY Maximum inlet pressure is 100 psi 6 9 bar Install the shielding gas supply as follows 1 Secure the cylinder to prevent it from falling 2 Remove the cylinder cap Inspect the cylinder valves and regulator for damaged threads dirt dust oil or grease Remove dust and dirt with a clean cloth DO NOT ATTACH THE REGULATOR IF OIL GREASE OR DAMAGE IS PRESENT Inform your gas supplier of this condition Oil or grease in the presence of high pressure oxygen is explosive 3 Stand to one side away from the outlet and open the cylinder valve for an instant This blows away any dust or dirt which may have accumulated in the va
35. N e 5 6 915 2 8 5 5 45 ojo 587 608 558 601 589 COMMON ANALOG P C BOARD sso 515 605 607 Y mnr Hi 12 3 4 5 6 7 8 9 10111213141516 5 6 3 5 9 101112 13 14 15 16 17111171111111111 11111111 NOTES CAVITY NUMBERING SEQUENCE AS VIEWED SIDE OF BOARD N B CAVITY NUMBERING SEQUENCE AS VIEWED FROM LEAD SIDE OF CONNECTOR N C TOGGLE SWITCHES AND POTENTIOMETERS SHOWN FROMCONNECTION SIDE OF SWITCH N D PIN NEAREST THE FLAT EDGE OF LEDLENS ALIGNS WTHWHITE LEAD OF LED SOCKET Return to Section TOC Return to Master TOC NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual The wiring diagram specific to your code is pasted inside one of the enclosure panels of your machine LINCOLN LF 72 74 ELECTRICAL DIAGRAMS Ga WIRING DIAGRAM ENTIRE MACHINE CODE 11209 11210 11211 11227 L12146 1 LF 72 CAVITY NUMBERING SEQUENCE COMPONENT SIDE OF P C BOARD ELECTRICAL SYMBOLS PER E1537 AFP E wre FEED 576A SPEED B BLACK 577 gt 577 12451 575A W WHITE 4 U BLUE Return to Section Return to Master TOC INPUT ELECTROLE CABLE CONNECTION Return to Master TOC BAFFLE MOUNTED RECTIFIER DIODE BRIDGE Ret
36. RAYS can burn RZ e Wear eye ear and body protection Observe additional guidelines detailed in the beginning of this manual The serviceability of product structure utilizing the LF 72 wire feeder is and must be the sole respon sibility of the builder user Many variables beyond the control of The Lincoln Electric Company affect the results obtained in using the LF 72 wire feeder These variables include but are not limited to weld ing procedure plate chemistry and temperature weldment design fabrication methods and service requirements The available range of the LF 72 wire feeder may not be suitable for all applications and the builder user is and must be solely responsible for welding settings GRAPHIC SYMBOLS THAT APPEAR ON THIS MACHINE OR IN THIS MANUAL COLD FEED POSITIVE OUTPUT NEGATIVE OUTPUT PROTECTIVE GROUND WARNING OR CAUTION DANGEROUS VOLTAGE 3 8 J e jy SHOCK HAZARD WELDING FUMES EXPLOSION GAS INPUT WORK CONNECTION LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 Return to Section TOC Return to Master TOC 2 D 2 8 3 COMMON WELDING ABBREVIATIONS WFS Wire Feed Speed CV Constant Voltage GMAW MIG Gas Metal Arc Welding
37. Section TOC Return to Master TOC 2 9 o gt 2 E OPERATION FRONT PANEL CONTROLS AND CONNECTIONS FIGURE B 1 CASE FRONT CONTROLS ITEM DESCRIPTION Location for Optional Remote Voltage Control See Accessory Section For Kit Number Location for Optional Burnback and Postflow Timer Kit See Accessory Section For Kit Number 3 1 2 Thermal LED Motor Overload 4 5 2 step Trigger Interlock switch Wire Feed Speed Knob 7 Gun Receiver Bushing BN Trigger Connector 5 amphenol for connecting the MIG gun trigger See Installation Section Cold Feed Gas Purge Switch press the switch up to feed wire with weld output off Press the switch down for gas flow with weld output off for detail LF 72 74 LINCOLN B Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC ojo 5 5 0 9 2 218 5 2 a Return to Section TOC Return to Master TOC B 5 1 REMOTE VOLTAGE CONTROL KIT The optional remote voltage control kit adjusts the arc voltage from the minimum to the maximum volt age of the welding power source Rotate the knob counterclockwise to reduce the arc voltage and rotate the knob clockwise to raise the arc voltage 2 BURNBACK AND POSTFLOW TIME
38. TOC Fg 515 0 9 2 2 SZ Return to Section TOC Return to Master TOC Return to Master TOC COAXIAL WELD CABLES Coaxial welding cables are specially designed welding cables for pulse welding or STT welding Coaxial weld cables feature low inductance allowing fast changes in the weld current Regular cables have a higher induc tance which may distort the pulse or STT wave shape Inductance becomes more severe as the weld cables become longer Coaxial weld cables are recommended for all pulse and STT welding especially when the total weld cable length electrode cable work cable exceeds 50 feet 7 6m ee Power Source Work Electrode Coaxial Weld Cable 6 INSTALLATION A 6 A coaxial weld cable is constructed by 8 small leads wrapped around one large lead The large inner lead connects to the electrode stud on the power source and the electrode connection on the wire feeder The small leads combine together to form the work lead one end attached to the power source and the other end to the work piece See Coaxial weld Cable below WELD CABLE CONNECTION Connect a work lead of sufficient size between the proper output stud on the power source and the work Be sure the connection to the work makes tight metal to metal electrical contact Poor work lead connections can result in poor welding performance Wire Feeder
39. The Above For Gasoline Engines ARC WELDING CAN BE HAZARDOUS PROTECT YOURSELF AND OTHERS FROM POSSIBLE SERIOUS INJURY OR DEATH KEEP CHILDREN AWAY PACEMAKER WEARERS SHOULD CONSULT WITH THEIR DOCTOR BEFORE OPERATING Return to Master TOC Read and understand the following safety highlights For additional safety information it is strongly recommended that you purchase a copy of Safety in Welding amp Cutting ANSI Standard Z49 1 from the American Welding Society P O Box 351040 Miami Florida 33135 or CSA Standard W117 2 1974 A Free copy of Arc Welding Safety booklet E205 is available from the Lincoln Electric Company 22801 St Clair Avenue Cleveland Ohio 44117 1199 BE SURE THAT ALL INSTALLATION OPERATION MAINTENANCE AND REPAIR PROCEDURES ARE PERFORMED ONLY BY QUALIFIED INDIVIDUALS Return to Master TOC 2 D 2 8 E Return to Master TOC FOR ENGINE powered equipment 1 Turn the engine off before troubleshooting and maintenance work unless the maintenance work requires it to be running X 1 b Operate engines in open well ventilated areas or vent the engine exhaust fumes outdoors 1 c Do not add the fuel near an open flame weld ing arc or when the engine is running Stop the engine and allow it to cool before refuel ing to prevent spilled fuel from vaporizing on contact with hot engine parts and igniting Do not spill fuel when filling tank If fuel is spille
40. all machines covered by this manual LF 72 74 Return to Section TOC Return to Section TOC Return to Master TOC EJE 5 5 Tiu 9106 es 5 5 8 ojo Return to Section TOC Return to Master TOC Return to Master TOC oe ELECTRICAL DIAGRAMS ms SCHEMATIC ENTIRE MACHINE CODE 11195 11196 11197 G4942 LF 74 Values for CV300 Others may be different O0 VDC 0 5 8 Arc Volts 6 6 VDC 10 40 ArcVolts 75 15 CONTROL Located on VOLTAGE Front POTENTIOMETER TIN 3 OPTIONAL Connector located yay behind case front P7 284 pulses sec 100 IPM 1139 pulses sec 400 IPM 577 WIRE FEED Located on ois DAT canna Case Front Connector located jearbox ratio is 2 2 by sheet panel Motor is at electrode p bel fance 0 VDC MIN WFS POTENTIOMETER Leads Pass through yum potential 5 VDC MIN WFS Off 0 VDC 55 toroid 2 times ere n Motor is located V i x behind L4 s 1 m uei 5 glastic panel t C MOTOR 563 GEARBOX Located on Coil case back measures w To Power Source Electrode Connection 21 ohms GAS 1 6V 100 IPM SOLENOID 30 6V 800 IPM 553 c 552 err ree 5528 Located on Leads Pass through 12 TRIGGER toroid 3 times INPUT Case Front 556 ry 554 Fe TRIGGER Located on Case Front CONNECTOR 3 552
41. at the welding power source 2 Remove the O ring holding the ball bushing assembly to the back of the wire feeder Remove the ball bushing assembly FIGURE A 10b BALL 34 BUSHING 3 ASSEMBLY 73 3 Place K1546 xx conduit connector into the back of the wire drive Rotate the conduit connector to a position where the thumb screw does not interfere assembly to the back of the wire feeder Remove with the idle arm or door the ball bushing assembly 4 Tighten the set screw to secure the conduit connec tor in the wire drive FIGURE A 10a 5 Insert conduit through the sheet metal of the LF 72 15 and into the conduit connector Secure with the 54 thumb screw ASSEMBLY FIGURE A 11 SET 12 THUMB As 5 EG CONDUIT CONNECTOR Pur 22 77 CONDUIT 7 we 7 3 LF 72 74 LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 8 Return to Section TOC Return to Master TOC 2 9 o gt 2 tc A 17 ALUMINUM WIRE PREPARATIONS A 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 Welding with aluminum filler wires requires extra care Aluminum wire is softer and not as stiff as steel wires it is important to k
42. b Use suitable clothing made from durable flame resistant material to protect your skin and that of your helpers from the arc rays Protect other nearby personnel with suitable non flammable screening and or warn them not to watch the arc nor expose themselves to the arc rays or to hot spatter or metal 23 FUMES AND GASES can be dangerous 5 Welding may produce fumes and gases hazardous to health Avoid breathing these fumes and gases When welding keep your head out of the fume Use enough ventilation and or exhaust at the arc to keep fumes and gases away from the breathing zone When welding with electrodes which require special ventilation such as stainless or hard facing see instructions on container or MSDS or on lead or cadmium plated steel and other metals or coatings which produce highly toxic fumes keep exposure as low as possible and below Threshold Limit Values TLV using local exhaust or mechanical ventilation In confined spaces or in some circumstances outdoors a respirator may be required Additional precautions are also required when welding on galvanized steel The operation of welding fume control equipment is affected by various factors including proper use and positioning of the equipment maintenance of the equipment and the specific welding procedure and application involved Worker expo sure level should be checked upon installation and periodi cally thereafter to be certain it is within app
43. er direction INSTALLATION AA 15 3 Re install the retaining collar Make sure that the release bar snaps out and that the retaining collar fully engages the groove on the spindle FIGURE AA 10 Retaining Collar Loading 30 Ib 13 6 kg Readi Reels See Figure AA 11 A K363 P Readi Reel adapter is required for loading these spools on 2 51mm spindles 1 Squeeze the release bar on the retaining collar and remove it from the spindle 2 Place the Readi Reel adapter on the spindle align ing the spindle brake pin with one of the holes in the adapter 3 Re install the retaining collar Make sure that the release bar snaps out and that the retaining collar fully engages the groove on the spindle 4 Rotate the spindle and adapter until the retaining spring is at the 12 o clock position 5 Position the Readi Reel so that electrode de reels in the proper direction 6 Set one of the Readi Reel inside cage wires on the slot in the retaining spring 7 Lower the Read Reel to depress the retaining spring and align the other inside cage wires with the grooves in the adapter 8 Slide the cage all way onto the adapter until the retaining spring pops up fully Removing a Readi Reel 1 To remove a Readi Reel from the an adapter depress the retaining spring with a thumb while pulling the Readi Reel cage from the adapter with both hands Do not remove the adapter from the spindle LF 72 74 LINCOLN B INS
44. for easy and accurate adjustment of the wire feed speed The knob rotates 3 4 turn Turn the knob clockwise to increase the wire feed speed and counter clockwise to reduce the wire feed speed K2426 1 and K2426 2 models These wire feeders are factory configured for normal Speed operation The normal wire feed speed range is 100 to 800 in min 2 5 20 3 m min K2426 3 model The wire feed speed range on the extra torque model is 50 to 400 in min 1 3 10 2 m min 2 REMOTE VOLTAGE CONTROL KIT The optional remote voltage control kit adjusts the arc voltage from the minimum to the maximum voltage of the welding power source Rotate the knob counter clockwise to reduce the arc voltage and rotate the knob clockwise to raise the arc voltage 5 __6 4 7 3 8 2 9 5 10 E ARC VOLTS 3 BURNBACK AND POSTFLOW TIMER KIT The optional Burnback and Postflow Timer Kit gives control over the shielding gas at the end of the weld and prepares the end of the wire for the next arc start Additional shielding gas protection is often required when welding aluminum stainless steel or exotic alloys When stitch welding set the postflow time to maxi mum for best results Burnback Timer The burnback timer range is OFF to 0 25 seconds The burnback timer controls the additional amount of time the power source output remains ON after the wire drive has stopped feeding wire Burnback adjust ment prevents the wire fr
45. gt E 2 AR INSTALLATION AR TECHNICAL SPECIFICATIONS LF 74 Wire Feeder WIRE FEED SPEED RANGE WFS Range Wire Sizes WFS Range Wire Sizes K2426 1 Normal Speed 100 800 ipm 3 P 100 800 ipm 030 5 64 2 5 20 3 m min 0 6 1 6 2 5 20 3 m min 0 8 2 0mm K2426 2 Normal Speed 100 800 ipm 100 800 ipm 030 5 64 2 5 20 3 m min 0 6 1 6mm 25 20 3 m min 0 8 2 0mm K2426 3 Extra Torque 50 400 ipm 023 1 16 50 400 ipm 1 3 10 4m min 0 6 1 6mm 1 3 10 4m min 0 8 2 4mm CONTROL BOX WIRE DRIVE AND COMPLETE UNITS SPEC TYPE INPUT POWER PHYSICAL SIZE TEMPERATURE RATING Input Voltage Dimensions and Current Width Operating Storage 10 2 259 Base Model Dimensions A Height Width Weight 24 42VAC 15 3 13 0 70 5 Lbs 14 F to 104 F 40 F to 85 F 9 AMPS 389 mm 330 mm 32 0 Kg 10 C to 40 C 40 C to 85 C 50 60 Hz Dimensions A Height Width Weight LF 74 Bench 15 3 13 0 70 5 Lbs Heavy 389 mm 830 mm 32 0 Kg Duty Extra Torque WELDING CAPACITY RATING A Dimensions do not include wire reel ITEMS INCLUDED WITH EACH PRODUCT Wire Reel Stand Drive Roll Kit Control Cable Feeder K2426 2 Bench Model with Heavy Duty Wire 035 045 Combo 10Ft 3m Stand LF 74 Heavy Duty up to 60lb 0 9 1 2mm 27 k kg Coil
46. high performance motor gear box with an integrated tachometer OPERATION BB 3 General Functional Description The LF 74 fulfills the need for an economical wire feed er with a high performance wire drive Functional fea tures 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 tachome ter 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 Ib 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 DC 400 CV 300 DC 600 CV 305 DC 655 CV 400 Invertec V350 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 compatible with the LF 74 Gun bushings are required for welding guns that do not have
47. kneeling or lying if there is a high risk of unavoidable or accidental contact with the workpiece or ground use the following equipment Semiautomatic DC Constant Voltage Wire Welder DC Manual Stick Welder AC Welder with Reduced Voltage Control In semiautomatic or automatic wire welding the electrode electrode reel welding head nozzle or semiautomatic welding gun are also electrically hot Always be sure the work cable makes a good electrical connection with the metal being welded The connection should be as close as possible to the area being welded Ground the work or metal to be welded to a good electrical earth ground Maintain the electrode holder work clamp welding cable and welding machine in good safe operating condition Replace damaged insulation Never dip the electrode in water for cooling Never simultaneously touch electrically hot parts of electrode holders connected to two welders because voltage between the two can be the total of the open circuit voltage of both welders When working above floor level use a safety belt to protect yourself from a fall should you get a shock Also see Items 6 c and 8 LINCOLN ARC RAYS can burn 4 a Use a shield with the proper filter and cover plates to protect your eyes from sparks and the rays of the arc when welding or observing open arc welding Headshield and filter lens should conform to ANSI Z87 standards 4
48. liner and conduit Clean and make repairs as necessary Start welding again when the problem has been safely resolved For best results keep the gun cable and conduit as straight as possible Perform regular maintenance and cleaning on the gun liner conduit and gun Always use quality electrode such as L 50 or L 56 from Lincoln Electric 4 COLD FEED GAS PURGE SWITCH Cold Feed and Gas Purge are combined into a single spring centered toggle switch COLO FEED To activate Cold Feeding hold the switch in the UP position The wire drive will feed electrode but neither the power source nor the gas solenoid will be ener gized Adjust the speed of cold feeding by rotating the WFS knob Cold feeding or cold inching the electrode is useful for threading the electrode through the gun GAS PURGE Hold with toggle switch in the DOWN position to acti vate Gas Purge and let the shielding gas flow The gas solenoid valve will energize but neither the power Source output nor the drive motor will be turned on The Gas Purge switch is useful for setting the proper flow rate of shielding gas Flow meters should always be adjusted while the shielding gas is flowing 5 2 STEP TRIGGER INTERLOCK SWITCH The 2 Step Trigger Interlock switch changes the function of the gun trigger 2 Step trigger operation turns welding on and off in direct response to the trigger Trigger Interlock operation allows welding to continue when the trig
49. nut driver remove the 5 screws holding the cover Locate the control board see figure F 6 and remove the harness plugs on the control board Observe static electricity precautions Remove the 4 nuts holding the board using the 3 8 inch nut driver and remove the board REPLACEMENT PROCEDURE 1 Remove the new control board from the static bag and place it on the 4 studs Reassemble the 4 nuts and tighten hand tight Reassemble the harness plugs Reassemble the case LF 72 74 LINCOLN 5 F 16 CONTROL PC BOARD REMOVAL AND REPLACEMENT PROCEDURE Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 8 Return to Section TOC Return to Master TOC 2 9 o gt gt F 17 TROUBLESHOOTING AND REPAIR WIRE DRIVE MOTOR AND GEAR BOX REMOVAL AND REPLACEMENT PROCEDURE WARNING Service and repair should be performed by only Lincoln Electric factory trained personnel Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty For your safety and to avoid electrical shock please observe all safety notes and pre cautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to per form the test repairs safely contact the Li
50. push the gun bushing out of the wire drive Because of the preci sion fit light tapping may be required to remove the gun bushing FIGURE A 5 THUMB SCREW OUTER WIRE GUIDE SOCKET HEAD CAP SCREW LOOSEN TIGHTEN LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC ojo O 515 o 9 0 2 2 SZ Return to Section TOC Return to Master TOC Return to Master TOC A 12 7 Disconnect the shielding gas hose from the gun bushing if required 8 Connect the shielding gas hose to the new gun bushing if required 9 Rotate the gun bushing until the thumb screw hole aligns with the thumb screw hole in the feed plate Slide the gun receiver bushing into the wire drive and verify the thumb screw holes are aligned 10 Tighten the socket head cap screw 11 Insert the welding gun into the gun bushing and tighten the thumb screw Gun Receiver Bushing K1500 1 K466 1 Lincoln gun connectors Innershield and Subarc guns K1500 2 K466 2 K466 10 Lincoln gun connectors Magnum 200 300 400 guns and compatible with Tweco 4 K1637 7 Lincoln gun connectors Magnum 550 guns and compatible with Tweco 5 K1500 3 K466 3 Lincoln gun connectors K1500 4 compatible with Miller guns K1500 5 Compatible with Oxo guns K489 7 Lincoln Fast Mate guns INSTALLATION PRESSURE ARM ADJUSTMENT WA
51. replacement PC board NOTE It is desirable to have a spare known good PC board available for PC board troubleshooting NOTE Allow the machine to heat up so that all electrical components can reach their operating temperature 5 Remove the replacement PC board and substitute it with the original PC board to recreate the original problem a If the original problem does not reappear by substituting the original board then the PC board was not the problem Continue to look for bad connections in the control wiring harness junction blocks and terminal strips b If the original problem is recreated by the substitution of the original board then the PC board was the problem Reinstall the replacement PC board and test the machine 6 Always indicate that this procedure was followed when warranty reports are to be submitted NOTE Following this procedure and writing on the warranty report INSTALLED AND SWITCHED PC BOARDS TO VERIFY PROBLEM will help avoid denial of legitimate PC board warranty claims LF 72 74 LINCOLN B Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 8 e Return to Section TOC Return to Master TOC 2 9 o gt 2 LF 72 74 TROUBLESHOOTING amp REPAIR Observe Safety Guidelines detailed the beginning of this manual PROBLEMS SYMPTOMS T
52. spatter Clean and tighten all electrode and work connections Verify the gun bushing is tightly mounted to the wire drive Verify the gun is tightly mounted to the gun bushing Verify the proper polarity is being used for the weld proce dure Make sure the proper electrode stick out is being maintained Check the gas flow rate and mixture Control board may be faulty When the trigger is pulled the drive rolls spin but no arc voltage The arc burns back to the tip The gas continues to flow for a long time after the weld 1 Possible bad gun or faulty con nections in the heavy current carrying leads 2 Possible faulty control cable 3 Possible defective power Source 1 If timer kit is installed reduce the amount of burnback time 2 the timer kit is installed reduce the amount of post flow time Check all electrode and work connections Verify the the gun bushing is tight to the wire drive Verify gun is tightly mounted to the bushing Check the control cable and connectors for continuity cuts or broken pins Verify the power source is oper ating properly CAUTION If for any reason you do not understand the test procedures or are unable to perform the test repairs safely con tact the Lincoln Electric Service Department at 1 888 935 3877 for electrical troubleshooting assistance before you proceed LF 72 74 SINGLE DUAL LINCOLN Return to Section
53. to Section TOC 5 5 5 0 0 2 818 5 Return to Section TOC Return to Master TOC Return to Master TOC AM INSTALLATION FIGURE A 9 ADAPTER SPINDLE RETAINING SPRING WELD WIRE ROUTING The electrode supply may be either from reels Readi Reels spools or bulk packaged drums or reels Observe the following precautions a The electrode must be routed to the wire drive unit so that the bends in the wire are at a minimum and also that the force required to pull the wire from the reel into the wire drive unit is kept at a minimum o The electrode is hot when the gun trigger is pressed and must be insulated from the boom and structure If more than one wire feed unit shares the same boom and are not sharing the some power source output stud their wire and reels must be insulated from each other as well as insulated from their mounting structure LF 72 74 LINCOLN 5 RELEASE BAR RETAINING COLLAR Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 8 e Return to Section TOC Return to Master TOC 2 D 8 3 15 SHIELDING GAS CONNECTION CYLINDER may explode if damaged Keep cylinder upright and chained to 3 support Keep cylinder away from areas where it may be damaged Nev
54. your factory warranty For your safety and to avoid electrical shock please observe all safety notes and pre cautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to per form the test repairs safely contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed Call 1 888 935 3877 TEST DESCRIPTION This test will help determine if the diode bridge is receiving the power AC input voltages and is converting them to the correct DC output voltages MATERIALS NEEDED 5 16 in nut driver 42VAC power supply Volt Ohmmeter LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 8 e Return to Section TOC Return to Master TOC 2 9 o gt 2 TROUBLESHOOTING AND REPAIR Ede DIODE BRIDGE TEST continued FIGURE F 4 CONTACTOR TEST PROCEDURE 1 Remove the input power from the unit 2 Using a 5 16 nut driver remove the 5 screws holding the cover 3 Apply the correct input voltage 42VAC to the LF72 LF74 unit 552B 552A 4 Check for the correct input voltage at leads 41 and 42 on the bridge the input voltage is not there check the wiring back to the receptacle assembly pins and K Check for the proper output on leads 580 negative and 522
55. 000 10035 METAL FILM 1 10W 100K 196 80805 e R123 R124 R125 NA CAUTION TE DEVICES TO DAMAGE BY STATIC ELECTRICITY ROS R67 R84 R87 RESISTOR SMD METAL FIM TOW 2 21K 50805 R89 R106 R115 SECURE P C BOARD ASSEMBLY WITH ITEM 3 2 PLACES 5 3 5 IN LBS N C PLACE BARCODED ASSEMBLY NUMBER IDENTIFICATION AND BARCODED R26 R27 R96 R131 2 SERIAL NUMBER IDENTIFICATION IN AREA SHOWN ND CONNECTORS MUST BE GREASED WITH ITEM 5 PRIOR TO ENCAPSULATION Ra RESISTOR SMD 1W200K1 NE ENGAPSU ATION PER A MINIMUM DEPTH SUCH THAT ALL R08 2800 482288 T RESISTOR SMD 43 2K AW OB TTR E B ren BI M PLOG SHOULD BE INSERTED BELOW CONNECTOR N H PARTS SHOWN MUST BE COMPLETELY COVERED WITH ENCAPSULATION R38 R37 R40 R41 R42 m PLACE ASSEMBLY NUMBER IDENTIFICATION IN AREA SHOWN R43 R44 R45 R46 R67 fies E R38 39 136 R47 R117 S25000 30008MT RESISTOR SMD METAL FILM 1 10W 9010HMS 156 0805 O 8 ra RESISTOR SMD METAL FILM 1 10W 1 50 125 50805 R49 d 4 NOTE G4415 2 MUST BE REVIEWED WHEN REO c 6 MODIFYING THIS BOARD R55 R81 R82 RESISTOR SMD METAL FILM 1 16W 10 0K 196 S0603 0 R58 R59 R62 R63 525012 10015 RESISTOR SMD METAL FILM 1 16W 1 00K 196 50603 4106 RES R70 u UNLESS OTHERWISE SPECIF
56. 16 nut driver remove the 5 screws holding the cover 8 Using the 7 16 inch socket wrench and extension remove the six mounting bolts See figure F 7 The motor and gear box assembly can now be removed from the LF72 LF74 unit 4 Using the Phillips head screw driver remove the 67 electrode sense lead from the connection block 5 Using the pliers remove the gas hose from the connection block Be careful not to damage the hose LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC ojo O 5 5 0 2 818 SZ Return to Section TOC Return to Master TOC TT TROUBLESHOOTING AND REPAIR ilii WIRE DRIVE MOTOR AND GEAR BOX REMOVAL AND REPLACEMENT PROCEDURE Continued REMOVAL OF THE DRIVE REMOVAL OF THE GEAR BOX MOTOR FROM THE GEAR BOX FROM THE MOUNTING PANEL 1 Using the 7 16 in wrench remove the 6 Follow the first five steps found in the cover from the gear box See Figure F 7 drive motor removal Hote ie Eta Only One screw 7 Using the 7 16 wrench remove the four 2 Loosen and remove the outer wire guide bolts holding the gear box to the panel 3 Loosen and remove the drive roll assembly The LF72 has one while the LF74 has three 4 Using the Phillips head screw driver remove the gear drive Figure 7 5 Using the phillips head screw driver remove the three screws hol
57. 2 G 8 Schematic Entire Machine Code 11195 11196 11197 G4942 74 G 9 5 Schematic Common Analog Control PC Board 84559 Sheet 1 G 10 gt Schematic Common Analog Control PC Board G4559 Sheet 2 G 11 5 Schematic Common Analog Control PC Board 04559 Sheet 3 G 12 Board Assembly Common Analog Control G4560 2E0 G 13 2 8 5 2 8 5 LF 72 74 LINCOLN B G ELECTRICAL DIAGRAMS WIRING DIAGRAM ENTIRE MACHINE CODE 11075 11076 11077 112146 LF 72 CAVITY NUMBERING SEQUENCE Sea COMPONENT SIDE OF P C BOARD ELECTRICAL SYMBOLS PER E1537 eps wee Fen SPEED COLOR CODE 577 5 CONTROL W WHITE POTENTIOMETER R RED U BLUE Return to Section TOC Return to Master TOC 75 76 TIA 77 INPUT ELECTROLE CABLE CONNECTION 5 NB Return to Master TOC BAFFLE MOUNTED RECTIFIER DIODE BRIDGE Return to Section TOC 14 PIN AMPHENOL CONNECTOR TO POWER SOURCE CONTROL p l au E b rm K ARC VOLTAGE L TH SENSE
58. 2 8 5 Return to Master TOC POWER FEED 10M SINGLE DUAL LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 515 0 2 218 SZ Return to Section TOC Return to Master TOC BB 2 SAFETY PRECAUTIONS Read this entire section of operating instructions before operating the machine A WARNING ELECTRIC SHOCK can kill Unless using cold feed feature when feeding with the gun trigger the elec trode and drive mechanism are always electrically energized and could remain energized several sec onds after welding ceases Do not touch electrically live parts or electrodes with your skin or wet clothing Insulate yourself from the work and ground Always wear dry insulating gloves ONLY QUALIFIED PERSONS SHOULD INSTALL USE OR SERVICE THIS EQUIPMENT READ AND FOLLOW THE MANUFACTURER S INSTRUCTIONS EMPLOYER S SAFETY PRACTICES AND MATERI AL SAFETY DATA SHEETS MSDS FOR CONSUM ABLES READ THIS WARNING PROTECT YOURSELF amp OTHERS FUMES AND GASES can be dangerous Keep your head out of fumes 23 Use ventilation or exhaust at the arc or both to keep fumes and gases m 0 from your breathing zone and al area WELDING SPARKS can cause fire or explosion a gt Do not weld near flammable material e Do not weld on c
59. 2 VAC OPTIONAL REMOTE VOLTAGE CONTROL CONTROL BOARD WIRE DRIVE RECEPTACLE To Gun Trigger COLD FEED GAS PURGE WIRE FEED SPEED POT The LF72 and LF74 are single head 24vac or 42vac input 2 roll LF72 or 4 roll LF74 wire feeders They have a single calibrated control for wire feed speed WFS and an optional K2339 1 remote voltage control kit to be used in conjunction with a Lincoln constant voltage CV direct current DC power source The LF72 and LF74 offer the user 3 individual features Cold feed trigger interlock 2 step trigger control and gas purge Presettable burnback and postflow timers are also available with an optional K2330 1 timer kit GENERAL DESCRIPTION The motor is equipped with a 3 75amp current over draw protection circuit which is indicated by a THER MAL LED located on the case front TRIGGER INTERLOCK 2 STEP INPUT RECEPTACLE CONTROL BOARD AND OPERATOR CON TROLS The 24 or 42 volt input is applied to the LF72 or LF74 through the 14 pin amphenol type connector The remote trigger leads are accessed through 14 pin receptacle The input voltage is rectified by a full wave bridge and is sent to a switching power supply in the control board where it is filtered This filtered DC volt age is applied to a switching power supply The switching power supply manufactures 15vdc and 5vdc regulated supplies for the control board circuit ry The control board r
60. 35 K468 203mm diameter spools on 2 in 51 mm spindles K468 1 Spindle Adapter for mounting 2 5 in 64mm diameter spools on 2 in 51 mm spindles K363P Readi Reel Adapter for mounting 23 30 Ib 10 4 13 6 kg reels to 2 51 mm spindles K438 K1504 1 Coil Adapter for mounting 50 60 Ib 22 7 27 2 kg coils to 2 in 51 mm spindles For use with heavy Duty Bench Spindle Adapter for mounting 14 Ib 6 4 kg Innershield Coils on 2 in 51 mm spindles Spindle Adapter for mounting 8in Readi Reel Adapter for mounting 50 60 Ib 22 7 27 2 kg reels to 2 in 51 mm spindles For use with Heavy Duty Bench models Includes Gun receiver bush ing with trigger connector Includes Incoming bushing and hex key wrench Includes Incoming bushing and hex key wrench Includes Spindle Adapter made from 2 coil retainers Electrode not included Includes Spindle Adapter Includes Spindle Adapter Includes Readi Reel spool adapter Spool of electrode not included K466 2 Magnum 200 300 400 to K1500 2 Includes Gun adapter cotter Adapter pin hex key wrench wrench 2 Includes Readi Reel spool adapter Spool of electrode not included Includes 50 60 Ib 22 7 27 2 kg coil adapter LF 72 74 LINCOLN 5 4 Includes Trigger adapter gun adapter and hex key wrench 9 gt Return to Section TOC Return to Master TOC Return to Section T
61. 6m K1841 xx Weld Power Cable cables Twist Mate to Twist Mate Includes Twist Mate to Twist Mate 2 0 Cable for 50 15 2m cables Includes Lug to Lug 3 0 Cable of length xx for K1842 xx Weld Power Cable Lug to Lug lengths up to 60 18 3m Lug to Lug 4 0 Cable of length xx for lengths greater than 60 18 3m 5 5 0 9 0 2 218 cic SZ a Return to Section TOC Return to Master TOC LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC ojo O 5 5 0 2 218 cic SZ Return to Section TOC Return to Master TOC Return to Master TOC CC 3 K1797 xx K2335 1 K1520 1 K1798 Adapter Cable for Control Cable to Includes Terminal Strip Power Sources K910 1 Ground Clamp Includes One 300 Amp K910 2 Ground Clamp Includes One 500 Amp Ground Clamp K1500 2 standard on all LF 74 s ACCESSORIES OPTIONAL KITS Control Cable Adapter for Miller Power Sources 42 Volt Transformer Kit Gun Receiver Bushing for guns with K466 1 Lincoln gun connec tors Innershield and Subarc Gun Receiver Bushing for guns with K466 2 K466 10 Lincoln gun connec tors Magnum 200 300 400 guns and compatible with Tweco 2 4 Gun Receiver Bushing for guns with K613 7 Lincoln gun connec tors Magnum 550 guns and com patible with Tweco 5 Gun Receiver
62. 8 Timer Board Summary Has potentiometers for burnback and postflow Preflow fixed at 30msec Burnback range is 0 to 0 25 sec range is 0 25 to 10 sec cien Receives Gas Flow Enable signal Outputs 100 msec pulses to turn Gas Flow On Gas Flow Off Located on Sheet Panel THERMAL LED Connector located on sheet panel Lights when motor current exceeds 1W 3 75 Amps for 5 VDC when lit Leads Pass extended time through lotor Connecter Summary toroid 2 times High Torque Setting engages Leads Pass 15 VDC Open COLD FEED Machine Select by connecting Pins 1 through 0 VDC Closed Located toroid 2 ses 12 and 2 on Connector J 2 tim Case Front E High Torque not available on Normal d 51 Ly UE Lj Speed Model Located on Leads Normal Speed Setting not available Case Back SRE E through 455 1 on High Torque Model EDU GAS PURGE SENSE toroid 2 ici times 16 J TRIGGER S 6 INTERLOCK aima Located on 589 Case Front 20 OHM OUTPUT ENABLED 52 HIGH IMPEDANCE OUTPUT DISABLED Trigger Interlock does not 42VAC input NOT USED NOT USED stop welding when the with control arc is broken Pull and board 15 VDC in release trigger to end the disconnected weld 60VDC with control board connected Start Up On power up th
63. BTOASA G4560 2 3 5 8 21 UF ojo NOTE Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting PC Board repairs will invalidate your factory warranty Individual Printed Circuit Board Components are not available from Lincoln Electric This information is pro vided for reference only Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in danger to the Machine Operator or Technician Improper PC board repairs could result in damage to the LINCOL ine LINCOLN machine LF 72 74
64. Bushing for gun with K466 3 Lincoln gun connec tors compatible with Miller guns Gun Receiver Bushing compatible with Oxo guns Includes 14 pin to 14 pin wire feeder to power source control cable Includes Adapter control cable for connecting a Lincoln 42 VAC wire feeder to a 24 VAC Miller power source Includes One transformer kit for operating a 42 VAC wire feeder on a power source supplying only 115 VAC Includes Gun receiver bush ing set screw and hex key wrench Includes Gun receiver bush ing with hose nipple set screw and hex key wrench Includes Gun receiver bush ing with hose nipple set screw and hex key wrench Includes Gun receiver bush ing with hose nipple set screw and hex key wrench Includes Gun receiver bush ing with hose nipple 4 guide tubes set screw and hex key wrench LF 72 74 LINCOLN 5 CC 3 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 Return to Section TOC Return to Master TOC 2 D 8 CC 4 ACCESSORIES OPTIONAL KITS K489 7 Gun Receiver Bushing for Lincoln Fast Mate guns Magnum 550 to K1500 3 Adapter K613 7 Lincoln Conduit K1546 1 Incoming Bushing for Lincoln Conduit 025 1 16 0 6 1 6mm wire K1546 2 Incoming Bushing for Lincoln Conduit 1 16 1 8 1 6 3 2 mm wire K4
65. Drive Motor and Tach Feedback F 7 F 8 Gas Solenoid TeSt F 9 F 10 Diode Bridge TeSt isse eiecit oet cei ann F 11 F 12 Wire Speed Potentiometer 5 F 13 F 14 Replacement Procedures PC Board Removal and F 15 F 16 2 Wire Drive Motor and Gear Box Removal and Replacement F 17 F 20 c 3 Retest After F 21 2 i 2 2 E i 2 2 LF 72 74 SINGLE DUAL LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC 515 0 2 2 515 Return to Section TOC Return to Master TOC Return to Master TOC TROUBLESHOOTING amp REPAIR HOW TO USE TROUBLESHOOTING GUIDE CAUTION Service and repair should be performed by only Lincoln Electric Factory Trained Personnel Unauthorized repairs performed on this equipment may result in danger to the technician and machine operator and will invalidate your factory warranty For your safety and to avoid Electrical Shock please observe all safety notes and precautions detailed throughout this manual This Troubleshooting Guide is provided to help you locate and repair possible machine malfunctions Simply follow the three step procedure listed below Step 1 LOCATE P
66. F 5 Return to Section TOC Return to Master TOC 577 WIRE FEED SPEED 576 10K 2W CONTROL 575 POTENTIOMETER Return to Section TOC Return to Master TOC ojo O 5 5 0 9 2 218 cic SZ a Return to Section TOC Return to Master TOC 0 VDC MIN WFS 5 VDC MIN WFS TEST PROCEDURE 1 2 Remove the input power from the unit Using 5 16 nut driver remove the 5 screws holding the cover Apply the correct input voltage 42VAC to the LF72 LF74 unit Locate the P8 plug see wiring diagram going to the potentiometer Check for OVDC minimum to 5VDC maximum between wires 575 and 576 If the voltage is not there check the wires for continuity back to the control board If the wiring checks out good the control board may be faulty The potentiometer can also be checked by unplugging the P8 connection see wiring diagram and checking for 0 to 10k ohms between leads 575 and 576 as pot is located Reconnect the disconnected leads and reassemble the cover LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 8 Return to Section TOC Return to Master TOC 2 9 o gt gt F 15 TROUBLESHOOTING AND REPAIR PC BOARD REMOVAL AND REPLACEMENT WARNING Service an
67. FCAW Cable Innershield or Outershield Flux Core Arc Welding PRODUCT DESCRIPTION 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 Ib 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 straigh
68. IED R71 72 olo CAPACITANCE 2 RIS ME EANES RIA clic ps i ELE RIS R76 R77 R78 R79 R90 R91 R113 R92 R93 525000 33215 NC NG Rot 925365008 PRESISTOR STAND UP ALL COMPONENTS AND MATERIALS USED IN THIS ROS 525355 20 0 R97 R98 NNNM TORE ROHS R107 RISE RIS S25000 20005MT REVISION CONTROL RI 54960 2 0 5127 R128 DENT EATON TEST PER E4124 RIS POT WITH E2527 __ S2so00 1s028uit__ RESISTOR SMD METAL FILM 95 90806 SCHEMATIC REFERENCE G4559 2E0 R139 525000 10028MT B T T il m eoe IRANSFORMERPWMFLYBACK ___________ O BUY DETAIL DETAIL x BUY PER E3867 MANUFACTURE PER E1911 ka SMD CMOS PSOC 8 BIT CY8C26443 5010 2889 j BUY BLANK COMPLETE nad amp OP AMP SMD QUAD TSS0P14 GEN PURPOSE 204P 6 BOARDS PER PANEL S 771 825068225 IC SMD CMOS DRIVER 1 CHANNEL IR21189 SOIC 88 E M LU 5 IC SMD VOLTAGE REGULATOR FIXED TERMINAL 0 6A 75V 0 4 LAYER BOARD BLANK PANEL x5 IC SMD CMOS INVERTER SCHMITT SINOLE SS SEE ELECTRONIC FILE FOR ADDITIONAL INFORMATION 9 55 5 i d Hn 8 DESIGN INFORMATION IREFERENCI Bs E monem SUBJECT COMMON ANALOG WIREDRIVE NUMBER revision WITH PUBLISHED STANDARDS MATERIAL APPROVAL PROJECT ORM
69. LOBAL INC 22s Y Y Y IRCUIT pesien nonam INFORMATION EQUIPMENT TYPE COMMON WIREDRIVE CONTROL OL OF 03 01 OF 03 PROGRAMMING DRAWN APMY 03050 DOCUMENT ____ ___ assem 16 FOR v l DIAGRAM MAY NOT SHOW THE EXACT SUBJECT I NUMBER REVISION 12222 PIN GZ FOR CoM COMPONENTS OR CIRCUTTRY OF CONTROLS AREY 4724 2006 1G 4559 2890 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual G 11 SCHEMATIC COMMON ANALOG CONTROL PC BOARD G4559 SHEET 2 ELECTRICAL DIAGRAMS G 11 Return to Section TOC Return to Master TOC 4 e 5 G o Blo PRIMARY POSITIVE fete 5 al alx ss AE 24 my ames 5 Ac oor 1 d 15 Bg ms 055A x 9 13 B e 3 4 25 75VDC 2 OPERATION 332 a OR 20 60VAC 392 010 4 19V 15 4 N
70. Master TOC Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC JE 5 2 olg 0 12 2 2 5 Return to Section TOC Return to Master TOC AA 9 Welding Gun Trigger Lead Gun Trigger __ Common Common pr HIGH FREQUENCY PROTECTION Locate the LF 74 away from radio controlled machin ery The normal operation of the LF 74 may adversely affect the operation of RF controlled equipment which may result in bodily injury or damage to the equipment REMOTE SENSE LEAD SPECIFICATIONS Refer to the power source instruction manual for instructions for connecting the wire feeder for STT welding WIRE DRIVE SYSTEMS Drive Roll Kits Steel Wires Includes 4 Smooth V groove drive rolls and inner wire guide KP1505 030S 023 030 0 6 0 8mm KP1505 035S 035 0 9mm KP1505 045S 045 1 2mm KP1505 052S 052 1 4mm KP1505 1 16S 1 16 1 6mm INSTALLATION WELDING GUN WIRE FEEDER TRIGGER CONNECTOR Wire Feeder Amphenol AA 9 Drive Roll Kits Cored Wires Includes 4 Knurled drive rolls and inner wire guide KP1505 035C KP1505 045C KP1505 052C KP1505 1 16C 030 035 0 8 0 9mm 040 045 1 0 1 2mm 052 1 4mm 1 16 1 6mm Drive Roll Kits Steel or Cored Wires Includes 4 Knurled drive rolls and inner wire guide KP1505 068 KP1505 5 64 KP1505 3 32 068 072 1 8mm 5 64 2 0m
71. OC Return to Master TOC 8 Return to Section TOC Return to Master TOC 2 D 8 ACCESSORIES sasha OPTIONAL KITS Includes Cover backing K1634 1 Plastic Wire Cover for 30 44 Ib plate wire conduit incoming 13 6 20 0 kg Wire packages bushing for 025 1 16 0 6 For use with Standard Duty 1 6 mm wire incoming bush Bench Models and Heavy Duty ing for 1 16 1 8 1 6 3 2 Bench Models mm wire thumb screw mounting hardware and hex key K1634 2 Plastic Wire Cover for up to 60 Ib 27 2kg Wire packages For use with Heavy Duty Bench Models K659 1 Gas Guard Regulator Includes Gas Guard Regulator and adjustment key Includes Gas Regulator for 3000290 Adjustable Gas Regulator Mixed Gases and 10 3 0m Hose Includes Deluxe Gas K586 1 Deluxe Adjustable Gas Regulator Regulator for Mixed Gases Adapter for CO2 and 10 3 0m Hose K1524 3 Heavy Duty Universal Wire Reel Includes Heavy Duty Wire Stand For spools up to 60 Ib Reel Stand 27 2kg 4 Wheeled Wire Feeder Includes Undercarriage with K163 Undercarriage For use with 8 208mm rear wheels 4 Standard Duty Bench Models and 102mm casters Heavy Duty Bench Models K1557 1 Swivel Platform for use with Includes Swivel Platform and Heavy Duty Bench Models Tray K1556 1 Light Duty Caster Kit for use with Includes 2 Swivel Ca
72. PEN POSITION SLIDE DRIVE ROLL ON DRIVE HUB TRIANGULAR RING IN UNLOCKED POSITION TRIANGULAR RING IN LOCKED POSITION LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC ojo O 515 0 2 2 SZ Return to Section TOC Return to Master TOC Return to Master TOC AA 13 INSTALLATION PRESSURE ARM ADJUSTMENT WARNING ELECTRIC SHOCK can kill Turn the input power OFF at the welding power source before installation or changing drive rolls and or guides Do not touch electrically live parts When inching with the gun trigger electrode and drive mechanism are hot to work and ground and could remain energized several seconds after the gun trigger is released Only qualified personnel should perform mainte nance work The pressure arm controls the amount of force the drive rolls exert on the wire Proper adjustment of both pressure arm gives the best welding performance For best results set both pressure arms to the same value Set the pressure arm as follows See Figure AA 8 Aluminum wires between 1 and 3 Cored wires between 3 and 4 Steel Stainless wires between 4 and 6 FIGURE AA 8 CORED WIRES SOLID WIRES ALUMINUM OUTERSHIELD METAL SHIELD INNERSHIELD STEEL STAINLE SS LF 72 74 LINCOLN AA 13 Return to Section TOC Return to
73. R KIT The optional Burnback and Postflow Timer Kit gives control over the shielding gas at the end of the weld and prepares the end of the wire for the next arc start Additional shielding gas protection is often required when welding aluminum stainless steel or exotic alloys When stitch welding set the postflow time to maxi mum for best results Burnback Timer The burnback timer range is OFF to 0 25 seconds The burnback timer controls the additional amount of time the power source output remains ON after the wire drive has stopped feeding wire Burnback adjustment prevents the wire from sticking to the weld at the end of a weld and helps to condition the wire for the next weld To set the burnback time adjust the knob to approxi mately 0 03 seconds and then decrease or increase the time as desired BURNBACK POSTFLOW MIN MAX MIN MAX 0 SECS 0 25 SECS 0 10 5 5 Postflow Timer The postflow timer range is OFF to 10 seconds Postflow is the time from when the power source out put turns OFF until the postflow timer expires Use postflow to protect the weld while the weld cools OPERATION Bes 3 THERMAL LED MOTOR OVERLOAD The thermal light illuminates when the wire drive motor draws too much current If the thermal light illu minates the wire drive will automatically shutdown for up to 30 seconds to allow the motor to cool To start welding again release the gun trigger inspect the gun cable
74. RE DRIVE MOTOR AND GEAR BOX REMOVAL AND REPLACEMENT TROUBLESHOOTING AND REPAIR Fl RETEST AFTER REPAIR Retest a machine e If it is rejected under test for any reason that requires you to remove any part which could affect the machine s electrical characteristics Return to Section TOC Return to Master TOC OR f you repair or replace any electrical components SET UP Connect a supply of filtered compressed air at 80 psi to the gas inlet Supply 42VAC to the machine Connect the gun to the connector block OPERATION VERIFICATION Return to Section TOC Return to Master TOC Close the idle arms and the pressure arms Activate the cold feed switch Verify the drive rolls are spinning in the forward direction Adjust the wire speed knob from min to max and verify the speed is changing Release the cold feed switch and verify that the drive rolls stop abruptly Activate the gas purge switch and verify that there is gas flow Release the gas purge switch and verify the gas flow stops Place the 2 step trigger interlock switch in the trigger interlock position Activate the gun trigger and verify the drive rolls spin 10 Release the gun trigger and verify the drive rolls continue to spin 11 Activate and release the gun trigger and verify the drive rolls stop abruptly 12 Place the 2 step trigger interlock switch in the 2 step position pice pa moet 5 5 0 9
75. RNING ELECTRIC SHOCK can kill Turn the input power OFF at the welding power source before instal lation or changing drive rolls and or guides Do not touch electrically live parts When inching with the gun trigger electrode and drive mechanism are hot to work and ground and could remain energized several seconds after the gun trigger is released Only qualified personnel should perform mainte nance work The pressure arm controls the amount of force the drive rolls exert on the wire Proper adjustment of the pressure arm gives the best welding performance Set the pressure arm as follows See Figure A 6 Aluminum wires between 1 and 3 Cored wires between 3 and 4 Steel Stainless wires between 4 and 6 FIGURE A 6 CORED WIRES 4 SOLID WRES OUTERSHIELD 3 2 ALUMINUM METALSHIELD 4 INNERS HIELD 5 STEEL 6 STAINLESS r LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Ojo O Fg 5 5 5 2 9 2 2 2 Return to Section TOC Return to Master TOC Return to Master TOC A 13 WIRE REEL LOADING A WARNING Keep hands hair clothing and tools away from rotating equipment Do not wear gloves when threading wire or changing wire spool Only qualified personnel should install use or service this equipment Loading 10 to 15 Ib 4 5 6 8kg Spools
76. ROBLEM SYMPTOM Look under the column labeled PROBLEM SYMPTOMS This column describes possible symptoms that the machine may exhibit Find the listing that best describes the symptom that the machine is exhibiting Symptoms are grouped into three main categories Feeding Problems and Welding Problems Step 2 PERFORM EXTERNAL TESTS The second column labeled POSSIBLE AREAS OF MISADJUSTMENT S lists the obvious external possibilities that may contribute to the machine symptom Perform these tests checks in the order listed general these tests can be conducted without removing the case wrap around cover Step 3 PERFORM COMPONENT TESTS The last column labeled Recommended Course of Action lists the most likely components that may have failed in your machine It also specifies the appropriate test procedure to verify that the subject component is either good or bad If there are a number of possible components check the components in the order listed to eliminate one possibility at a time until you locate the cause of your problem All of the referenced test procedures referred to in the Troubleshooting Guide are described in detail at the end of this chapter Refer to the Troubleshooting and Repair Table of Contents to locate each specific Test Procedure All of the referred to test points components terminal strips etc can be found on the referenced electrical wiring diagrams and schematics Refer to t
77. Return to Master TOC Return to Master TOC m 7 o gt 2 tc Return to Master TOC View Safety Info View Safety Info 2 gt View Safety Info 1 72 74 For use with machines having Code Number 11075 thru 11293 Safety Depends on You Lincoln arc welding and cutting equipment is designed and built with safety in mind However your overall safety can be increased by proper installation and thoughtful operation on your part DO NOT INSTALL OPERATE OR REPAIR THIS EQUIPMENT WITHOUT READ ING THIS MANUAL AND THE SAFETY PRECAUTIONS CON TAINED THROUGHOUT And most importantly think before you act and be careful SERVICE MANUAL LINCOLN Copyright 2007 Lincoln Global Inc World s Leader in Welding and Cutting Products Sales and Service through Subsidiaries and Distributors Worldwide Cleveland Ohio 44117 1199 U S A TEL 1 888 935 3877 FAX 216 486 1751 WEB SITE www lincolnelectric com SAFETY WARNING CALIFORNIA PROPOSITION 65 WARNINGS A Diesel engine exhaust and some of its constituents are known to the State of California to cause can cer birth defects and other reproductive harm The engine exhaust from this product contains chemicals known to the State of California to cause cancer birth defects or other reproductive harm The Above For Diesel Engines
78. Return to Section TOC Return to Master TOC 521 BAFFLE MOUNTED 3 i RECTIFIER gt DIODE 1 gt BRIDGE M 2219 NE p 14 PIN CIRCULAR CONNECTOR TO POWER SOURCE Qjo O 5 6 915 2 8 5 5 45 ojo 587 608 1 558 601 589 559 515 605 607 Y 606 CAMTY NUMBERING SEQUENCE AS MEWED SIDE 1234567 8 9101112 i 16 1234567 8 9 1011121314 15 16 OF BO 1117711177777 777T NB CAVITY NUMBERING SEQUENCE AS VIEWED FROM LEAD SIDE OF CONNECTOR n 114 N C TOGGLESWITCHES AND POTENTIOMETERS SHOWN FROM COMMON ANALOG P C BOARD CONNECTIONSIDE OF SWITCH PIN NEAREST THE FLAT EDGE OF LEDLENS ALIGNS WTHWHITE LEAD OF LEDSOCKET NE P6 NOT USED Return to Section TOC Return to Master TOC NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual The wiring diagram specific to your code is pasted inside one of the enclosure panels of your machine LINCOLN LF 72 74 Gs ELECTRICAL DIAGRAMS aS WIRING DIAGRAM ENTIRE MACHINE CODE 11195 11196 11197 L12484 LF 74 CAVITY NUMBERING SEQUENCE GENERALINFORMATION COMPONENT SIDE OF P C BOARD M ELECTRICAL SYMBOLS PER E1537 WRE FEED j7 SPEED 9 2 9 COLOR CODE CONTROL B BLACK POTENTIOVETER WHITE RED BLUE
79. TALLATION ida FIGURE AA 11 ADAPTER SPINDLE RETAINING S Return to Section TOC Return to Master TOC GROOVES RETAINING COLLAR RELEASE BAR Return to Master TOC 9 e 2 o 8 c WELD WIRE ROUTING The electrode supply may be either from reels Readi Reels spools or bulk packaged drums or reels Observe the following precautions a The electrode must be routed to the wire drive unit so that the bends in the wire are at a minimum e 9 and also that the force required to pull the wire c E from the reel into the wire drive unit is kept at a 918 JE 2 b The electrode is hot when the gun trigger is pressed must be insulated from the boom and 515 structure C If more than one wire feed unit shares the same boom and are not sharing the some power source output stud their wire and reels must be insulated from each other as well as insulated from their mounting structure Return to Section TOC Return to Master TOC LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC ojo O 515 0 2 2 SZ Return to Section TOC Return to Master TOC AA 17 INSTALLING ELECTRODE CONDUIT KITS WARNING ELECTRIC SHOCK can kill Turn the input power OFF at the dis connect switch before work
80. TOC Return to Master TOC Return to Section TOC Return to Master TOC S o 9 8 a Return to Section TOC Return to Master TOC 2 7 9 o gt gt TROUBLESHOOTING amp REPAIR FS 2 Observe Safety Guidelines detailed in the beginning of this manual PROBLEMS SYMPTOMS POSSIBLE AREAS OF MISADJUSTMENT S FUNCTION PROBLEMS Continu The motor L12081 failed when a load 6 N m was applied to the wire drive When testing the wire drives for feeding problems inconsistent feeding grinding noises from the gearbox jumping drive rolls the wire drive should be tested under load RECOMMENDED COURSE OF ACTION This can be done by loading a spool of wire setting the spindle brake to maximum and hen feed ing wire CAUTION If for any reason you do not understand the test procedures or are unable to perform the test repairs safely con tact the Lincoln Electric Service Department at 1 888 935 3877 for electrical troubleshooting assistance before you proceed LF 72 74 LINCOLN TROUBLESHOOTING amp REPAIR DRIVE MOTOR AND TACH FEEDBACK TEST WARNING Service and repair should be performed by only Lincoln Electric factory trained personnel Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your
81. TRIC 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 MAINTENANCE DD 2 Calibration of the LF 74 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 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 MODEL WFS knob setting K2426 1 K2426 1 K2426 3 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 TABLE D 2 Only qualified personnel should perform mainte nance work MODEL WIRE LENGTH K2426 1 2426 1 50 inches 5 inches 1270 mm 127mm K2426 3 25 inches 2 5 inches 635 mm 64 mm Return to Section TOC Return to Master TOC 8
82. a Magnum Tweco 2 4 compatible back end The LF 74 does not attach to K303 or K377 wire reel stands LF 72 74 LINCOLN B BB 4 OPERATION BB 4 FRONT PANEL CONTROLS AND CONNECTIONS FIGURE BB 1 CASE FRONT CONTROLS NH Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC ITEM DESCRIPTION Wire Feed Speed Knob Location for Optional Remote Voltage Control See Accessory Section For Kit Number Location for Optional Burnback and Postflow Timer Kit See Accessory Section For Kit Number ojo 515 o 9 2 2 SZ Thermal LED Motor Cold Feed Gas Purge Switch press the switch up to feed wire with weld output off Press the switch down for gas flow with weld output off 2 step Trigger Interlock switch Gun Receiver Bushing Trigger Connector 5 amphenol for connecting the MIG gun trigger See Installation Section for detail Return to Section TOC Return to Master TOC LF 72 74 LINCOLN B Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 515 9 5 2 g g Return to Section TOC Return to Master TOC BB 5 1 WIRE FEED SPEED KNOB The large calibrated wire feed speed knob makes
83. and welding power Source 5 Adjust the WFS knob per the Table D 1 6 Insert the shorting plug into the control p c board J2 shorts pins 1 and 5 See Figure 02 7 Wait a minimum of 1 second 8 Remove the shorting plug 9 Connect J2 of the harness to p c board 10 Turn off power to the LF 74 and welding power Source 11 Assemble the wraparound 12 Connect the electrode lead LF 72 74 LINCOLN B DD 3 oc l O 2 8 20 S O T Q 2 lt lt lt 210 or tr 15 D 5 5 ae gt WRAPAROUND DD 3 901 Je1se N 0 201 DOL 01 201 ISEW 01 DOL uonoeg DOL DOL Uonoeg UNH 901 DD 4 MAINTENANCE LF 72 74 LINCOLN FIGURE DD 3 MAJOR COMPONENT LOCATION 2 Wire Drive Assembly 3 Wire Reel Stand LF 72 4 Wire Reel Stand LF 74 1 Center Assembly DD 4 DOL 01 DOL Je1se N DOL 01 201 ISEW 01 DOL uonoeg uunjeH DOL uonoeg DOL 901 Return to Master TOC Return to Master TOC
84. ave other health effects which are now not known All welders should use the following procedures in order to minimize exposure to EMF fields from the welding circuit 2 d 1 Route the electrode and work cables together Secure them with tape when possible 2 d 2 Never coil the electrode lead around your body 2 d 3 Do not place your body between the electrode and work cables If the electrode cable is on your right side the work cable should also be on your right side Connect the work cable to the workpiece as close as possible to the area being welded Do not work next to welding power source LINCOLN Return to Master TOC Return to Master TOC 2 D 8 E Return to Master TOC SAFETY i ELECTRIC SHOCK can kill 3 a The electrode and work or ground circuits are electrically hot when the welder is on Do not touch these hot parts with your bare skin or wet clothing Wear dry hole free gloves to insulate hands 3 b Insulate yourself from work and ground using dry insulation Make certain the insulation is large enough to cover your full area of physical contact with work and ground In addition to the normal safety precautions if welding must be performed under electrically hazardous conditions in damp locations or while wearing wet clothing on metal structures such as floors gratings or scaffolds when in cramped positions such as sitting
85. button or activating the gun trigger check for approximately 8VDC at the solenoid leads FIG F 3 If the 8VDC is present the solenoid should activate If the 8VDC is present but the solenoid does not activate the solenoid may be faulty FIGURE F 3 LEADS 552 552B amp 553 Off 0 VDC OCV 59 VDC On 7 7 VDC 553 Located on case back measures 21 ohms GAS SOLENOID 552 552B If the 8VDC is missing or low check the leads and connections between the solenoid and the control board See the wiring diagram If the leads and connections are ok the control board may be faulty Normal solenoid coil resistance is 21 ohms The solenoid can be further checked by disconnecting the leads and applying 12VDC directly to the terminals If the solenoid does not activate the solenoid is faulty Reconnect the leads and replace the cover LF 72 74 LINCOLN B Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 8 Return to Section TOC Return to Master TOC 2 9 o gt gt F 11 TROUBLESHOOTING AND REPAIR DIODE BRIDGE TEST WARNING Service and repair should be performed by only Lincoln Electric factory trained personnel Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate
86. c volts Referenced to pin D 151 Miller is a registered trademark owned or licensed by The Lincoln Electric Company LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC O 515 9 5 2 2 2 Return to Section TOC Return to Master TOC WELDING GUN WIRE FEEDER TRIGGER CONNECTOR Wire Feeder Amphenol Welding Gun fd ps HIGH FREQUENCY PROTECTION Locate the LF 72 away from radio controlled machin ery The normal operation of the LF 72 may adversely affect the operation of RF controlled equipment which may result in bodily injury or damage to the equipment INSTALLATION REMOTE SENSE LEAD SPECIFICATIONS Refer to the power source instruction manual for instructions for connecting the wire feeder for STT welding WIRE DRIVE SYSTEMS Drive Roll Kits are designed to feed specific types and wire sizes The LF 72 Bench Model comes with the combo KP1696 1 All other Drive Roll Kits listed are not included but are available for ordering from the fol lowing tables Drive Roll Kits Steel Wires Includes 2 Smooth V groove drive rolls and an inner wire guide KP1696 030S KP1696 035S KP1696 045S KP1696 052S KP1696 1 16S KP1696 1 KP1696 2 023 030 0 6 0 8mm 035 0 9mm 045 1 2mm 052 1 4mm 1 16 1 6mm 035
87. d wipe it up and do not start engine until fumes have been eliminated 1 d Keep all equipment safety guards covers and devices in posi tion and in good repair Keep hands hair clothing and tools away from V belts gears fans and all other moving parts when starting operating or repairing equipment some cases it may be necessary to remove safety guards to perform required maintenance Remove guards only when necessary and replace them when the maintenance requiring their removal is complete Always use the greatest care when working near moving parts 1 f Do not put your hands near the engine fan Do not attempt to override the governor or idler by pushing on the throttle control rods while the engine is running AX To prevent accidentally starting gasoline engines while turning the engine or welding generator during maintenance work disconnect the spark plug wires distributor cap or magneto wire as appropriate 1 h To avoid scalding do not remove the radiator pressure cap when the engine is hot ELECTRIC AND MAGNETIC FIELDS may be dangerous 9 S 2 a Electric current flowing through any conductor causes localized Electric and Magnetic Fields EMF Welding current creates EMF fields around welding cables and welding machines EMF fields may interfere with some pacemakers and welders having a pacemaker should consult their physician before welding Exposure to EMF fields in welding may h
88. d repair should be performed by only Lincoln Electric factory trained personnel Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty For your safety and to avoid electrical shock please observe all safety notes and pre cautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to per form the test repairs safely contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed Call 1 888 935 3877 TEST DESCRIPTION This procedure will aid the technician in the removal and replacement of the control pc board MATERIALS NEEDED 5 16 in nut driver 3 8 in nut driver Anti static strap LF 72 74 LINCOLN 5 F 15 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC ojo O 5 5 0 9 2 2 lt SZ Return to Section TOC Return to Master TOC F 16 TROUBLESHOOTING AND REPAIR Continued Figure F 6 PC Board Location e q 4 i e b 2 CONTROL BOARD REMOVAL PROCEDURE Remove the input power 42VAC from the LN72 LN74 unit Using the 5 16
89. d speed and counter clockwise to reduce the wire feed speed Return to Section TOC Return to Master TOC The wire feed speed range is 50 to 800 in min 1 27 20 3 m min 7 GUN RECEIVER BUSHING K1500 2 K1500 2 bushing is standard on all LF 72 s This Gun Receiver Bushing is used with Lincoln gun connectors also with Magnum 200 300 400 guns and compatible with Tweco 4 8 TRIGGER CONNECTOR 5 PIN AMPHENOL This is used for connecting the MIG gun trigger See Installation Section for detail 515 0 9 2 218 SZ Return to Section TOC Return to Master TOC LF 72 74 LINCOLN 5 Section C 1 TABLE OF CONTENTS Section C 1 ACCESSORIES SECTION cuaaucaadusvacuddaduvsecsiaauasccucuadtessaxdanasbeccctax Section C General Options Accessories C 2 C 5 Return to Master TOC Return to Master TOC 2 D 2 8 5 Return to Master TOC LF 72 74 SINGLE DUAL LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC olo Pg 515 9 0 12 218 elt 5 5 Return to Section TOC Return to Master TOC Return to Master TOC c2 ACCESSORIES dn OPTIONAL KITS Includes 10k potentiometer 24 gt K2329 1 Remote Voltage Control Kit harness knob and decal with a 0 10
90. ding power source The control board receives a tach feed back signal and adjusts the motor armature voltage to match the preset wire feed speed O10 515 0 nl 2 SZ The control board also monitors the drive motor amperage and will shut down the wire drive for 30 to 60 seconds to allow the motor to cool if the amperage exceeds 3 75 amps for an extended time NOTE Unshaded areas of Block Logic Diagram are the subject of discussion Return to Section TOC Return to Master TOC LF 72 74 LINCOLN B E 4 2 E RE DOL 01 DOL Je1se N 901 Je1Se N 01 201 ISEW 01 E 4 DOL uonoeg DOL uonoeg DOL uunjeH 901 Section F 1 TABLE OF CONTENTS Section F 1 TROUBLESHOOTING amp REPAIR SECTION gt Troubleshooting amp Repair Section Section F IU VSHOUUIMM Gc rivis aar V ias inr ri 1 E E How to Use Troubleshooting F 2 PC Board Troubleshooting Procedures and F 3 Troubleshooting Guilde riter eee EE nda eir Een F 4 Test Procedures
91. ding the drive motor LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 Return to Section TOC Return to Master TOC 2 D 8 TROUBLESHOOTING AND REPAIR PROCEDURE Continued REPLACEMENT PROCEDURES Line up the gear box with the 4 holes on the panel Replace and tighten the four 1 4 20 x 1 2 in hex head bolts Insert the drive motor through the panel and gear box Line up and tighten the three M6 x 1 00 in Phillips pan head Screws Replace the drive gear and secure in place using the screw and lock washer previously removed Replace the drive rolls and secure the secure locking rings Replace the gear box cover and secure with the 1 4 20 hex head screws 6 Feed the gas hose and the 67 lead through the notch on the panel Feed the P10 plug through the center panel Align and mount and tighten the panel using the six lock washers and bolts previously removed Plug the P10 plug into the wiring harness Using the Phillips head screw driver connect the 67 electrode sense lead to the connector block Using the 3 4 in wrench connect the electrode lead to the connector block 10 Connect the gas hose 11 Install the cover using the five screws 12 Connect the gun LF 72 74 LINCOLN 5 F 20 WI
92. e LF 74 will light the motor thermal LED for 0 5 seconds If the feeder is powered up with the trigger depressed welding will not start until the trigger is released and then depressed again Notes The WFS range of this code of LF 74 is 100 800 ipm The WFS range of the LF 72 is 50 800 ipm Control Board Summary Has on board power supply Receives switch signals from Trigger Cold Feed Gas Purge Trigger nterlock Reads WFS potentiometer Communicates with optional timer kit to control burnback postflow Controls motor speed with PWM urns Gas Solenoid on off Reads the motor tachometer Monitors motor current lights yellow thermal LED if over 3 75 amps for an extended time period LED remains lit for 30 60 seconds to allow motor to cool Does NOT support Run in at this time Operates on 24 42 VAC Maximum WFS and or maximum pull force may be less when operating at 24 VAC Does NOT operate on 115 NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual LF 72 74 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC e 5 6 515 l 2 8 5 5 45 ojo Return to Section TOC Return to Master TOC e ELECTRICAL DIAGRAMS SCHEMATIC COMMON ANALOG CONTROL BOARD 64559 SHEET 1 n MOTOR DRIVE 1 425 75VDE m RI R77 ghax A
93. e LF 72 Ae INSTALLATION MOUNTING For location and size LF 72 Bench Model Rear Mounting Holes See Figure A 1 and for Bottom Mounting Holes See Figure A 2 FIGURE A 1 FIGURE A 2 LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC FIR 55 0 9 2 218 cic 5 2 Return to Section TOC Return to Master TOC BENCH MOUNT The LF 72 mounts in a variety of configurations As shipped from the factory the LF 72 is suitable for bench mounting or placing directly on top of the weld ing power source CV xxx and DC xxx product family only Bench Mount SWIVEL MOUNT Both the standard duty bench model and heavy duty bench model may be mounted onto a swivel when a top a welding power source Swivel Kit and Bench Model Standard Duty Swivel Kit and Base Model LF 72 INSTALLATION n BOOM MOUNT When boom mounting remove the wire reel stand if assembled and secure the wire feeder directly to the desired surface SUSPENDED Only suspend the wire feeder by the lift bail of the portability kit A WARNING Alternative methods for hanging the wire feeder must not be used unless insulation is provided between the wire feeder enclosure and the hanging device LF 72 74 LINCOLN 5 5 INSTALLATION 5 SAFETY PRECAUTION 98 ELECTRIC SHOCK can kill Only qualified pe
94. e shorting plug shorts pins 1 amp 5 of connector J2 the p c board 2 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 LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 Return to Section TOC Return to Master TOC 2 D 8 3 Bs MAINTENANCE FIGURE D 1 4 Open the idle arm 5 Turn power on to the LF 72 6 Adjust the WFS knob to 300 ipm Center the knob pointer with the name plate graphics Activate the gun trigger 7 Insert the shorting plug into connector J2 on the p c board The shorting plug shorts pins 1 amp 5 See Figure D 2 8 Remove the shorting plug Set aside For Codes below 11289 use 9 thru 17 9 Adjust the WFS knob to minimum 10 Insert the shorting plug into connector J2 11 Adjust the WFS knob until the motor measures 51 5 5 ipm 9 5 1 0 rpm 12 Remove the shorting plug 13 Adjust the WFS knob to maximum 14 Insert the shorting plug into connector J2 15 Adjust the WFS until the motor measures 793 5 5 ipm 146 7 x 1 0 rpm 16 Remove the shorting plug 17 Release the gun trigger
95. eceives commands from the user operated controls for the wire feed speed WFS pot the optional timer kit and the optional voltage remote control kit It compares this feedback information with the user command signals and generates appropriate signals to control wire feed speed arc voltage and gas flow The control board is also responsible for the operation of the trigger interlock 2 step cold feed and the gas purge features of the LF72 and the LF74 LF 72 74 SINGLE DUAL LINCOLN THEORY OPERATION ES FIGURE E 3 DRIVE MOTOR TACH FEEDBACK AND GAS SOLENOID GAS SOLENOID 3 75 AMP OVERLOAD PROTECTION WIRE DRIVE MOTOR To Gun Trigger Return to Section TOC Return to Master TOC OPTIONAL OPTIONAL BURNBACK REMOTE TIMER VOLTAGE CONTROL WIRE DRIVE RECEPTACLE L CONTROL BOARD CE 14 PIN RECEPTACLE 24 42 VAC Return to Section TOC Return to Master TOC TRIGGER INTERLOCK DLSIED WIRE FEED SPEED POT DRIVE MOTOR TACH FEEDBACK AND GAS SOLENOID The leads to the drive motor gas solenoid and the tach hall effect device LF 74 and LF 72 above codes 11290 are brought into the control box via the 14 pin receptacle This 14 pin receptacle also houses the gun trigger leads and the voltage sense leads When the gun trigger is activated the control board energizes the gas solenoid the wire drive motor and the wel
96. eep 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 For Codes 11075 11076 11077 Tools required See Figure A 12a Snap Ring Pliers 9 64 Hex key wrench 1 Turn off power at the welding power source 2 Remove the snap ring holding the ball bushing assembly to the back of the wire feeder Remove the ball bushing assembly BALL BUSHING 5 ASSEMBLY INSTALLATION A 17 FIGURE A 12a For Codes 11209 11210 11211 and above Tools required See Figure A 12b 9 64 Hex key wrench 1 Turn off power at the welding power source 2 Remove the snap ring holding the ball bushing assembly to the back of the wire feeder Remove the ball bushing assembly BALL BUSHING ASSEMBLY O RING FIGURE A 12b 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 FIGURE A 13 HOUSING _ i BALL SCREW BEARINGS 4 Place the ball bushing housing into the wire feeder case and secure with the snap ring or O ring depending on which code your machine uses LF 72 74 LINCOLN A 18 5 gt 5 z T E gt lt E 2
97. eight LF 72 2327 2 24 42 12 6 10 9 22 5 52 5 Lbs 14 F to 104 F 40 F to 85 F Bench 9 AMPS 320 mm 277 mm 572 mm 23 8 Kg 10 C to 40 C 40 C to 85 C Standard Return to Section TOC Return to Master TOC Duty Dimensions A Height Width Depth Weight 15 3 13 0 27 0 67 5 Lbs 330 mm 30 6 Kg WELDING CAPACITY RATING Amp Rating Duty Cycle A Dimensions do not include wire reel 8 515 0 915 2 2 SZ Return to Section TOC Return to Master TOC LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 Return to Section TOC Return to Master TOC 2 D 8 SAFETY PRECAUTION ELECTRIC SHOCK can kill Only qualified personnel should perform this installation Turn off the input power to power source at the disconnect switch or fuse box before working on this equipment Turn off the input power to any other equipment connected to the welding system at the disconnect switch or fuse box before working on this equipment Do not touch electrically hot parts LOCATION The LF 72 may be placed on a bench or mounted on top of a welding power source Place the LF 72 in a clean and dry location Do not stack th
98. emove the sock et head cap screw 6 Remove the outer wire guide and push the gun bushing out of the wire drive Because of the pre cision fit light tapping may be required to remove the gun bushing gt GUN RECEIVER BUSHING SOCKET HEAD CAP SCREW INSTALLATION AA 11 7 Disconnect the shielding gas hose from the gun bushing if required 8 Connect the shielding gas hose to the new gun bushing if required 9 Rotate the gun bushing until the thumb screw hole aligns with the thumb screw hole in the feed plate Slide the gun receiver bushing into the wire drive and verify the thumb screw holes are aligned 10 Tighten the socket head cap screw 11 Insert the welding gun into the gun bushing and tighten the thumb screw Gun Receiver Bushing K1500 1 K466 1 Lincoln gun connectors Innershield and Subarc guns K1500 2 K466 2 K466 10 Lincoln gun connectors Magnum 200 300 400 guns and compatible with Tweco 2 4 K1637 7 Lincoln gun connectors Magnum 550 guns and compatible with Tweco 5 K1500 3 K466 3 Lincoln gun connectors K1500 4 compatible with Miller guns K1500 5 Compatible with Oxo guns K489 7 Lincoln Fast Mate guns FIGURE AA 5 TIGHTEN LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC ojo O 515 0 9 2 2 SZ
99. er lift welder with cylinder attached Never allow welding electrode to touch cylinder Keep cylinder away from welding or other live electrical circuits BUILD UP OF SHIELDING GAS may harm health or kill Shut off shielding gas supply when not in use SEE AMERICAN NATIONAL STANDARD 2 49 1 SAFETY IN WELDING AND CUTTING PUB LISHED BY THE AMERICAN WELDING SOCIETY Install the shielding gas supply as follows 1 Secure the cylinder to prevent it from falling 2 Remove the cylinder cap Inspect the cylinder valves and regulator for damaged threads dirt dust oil or grease Remove dust and dirt with a clean cloth DO NOT ATTACH THE REGULATOR IF OIL GREASE OR DAMAGE IS PRESENT Inform your gas supplier of this condition Oil or grease in the presence of high pressure oxygen is explosive 3 Stand to one side away from the outlet and open the cylinder valve for an instant This blows away any dust or dirt which may have accumulated in the valve outlet 4 Attach the flow regulator to the cylinder valve and tighten the union nut s securely with a wrench Note if connecting to 10096 CO cylinder insert reg ulator adapter between regulator and cylinder valve If adapter is equipped with a plastic washer be sure it is seated for connection to the CO cylinder INSTALLATION A 15 5 Attach one end of the inlet hose to the outlet fitting of the flow regulator Attach the other end to the welding system s
100. factory warranty For your safety and to avoid electrical shock please observe all safety notes and pre cautions detailed throughout this manual Return to Section TOC Return to Master TOC If for any reason you do not understand the test procedures or are unable to per form the test repairs safely contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed Call 1 888 935 3877 TEST DESCRIPTION This test will help determine if the wire drive motor is receiving the correct voltage and is capable of running properly It will also determine if the tach sensor is receiving the correct input from the control board and is sending back the correct signal Return to Section TOC Return to Master TOC MATERIALS NEEDED 5 16 in nut driver 32 VDC Q 1 amp variable power source Volt Ohm Meter 515 0 9 2 2 SZ Return to Section TOC Return to Master TOC LF 72 74 LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 8 Return to Section TOC Return to Master TOC 2 9 o gt gt 1 2 TROUBLESHOOTING amp REPAIR F 8 MOTOR AND TACH FEEDBACK TEST continued TEST PROCEDURE Remove power from the LF72 LF74 wire drive unit Using a 5 16 nut driver remove t
101. fer to Safety in Welding and Cutting ANSI Standard Z49 1 and the operating information for the equipment being used When not welding make certain no part of the electrode circuit is touching the work or ground Accidental contact can cause overheating and create a fire hazard Do not heat cut or weld tanks drums or containers until the proper steps have been taken to insure that such procedures will not cause flammable or toxic vapors from substances inside They can cause an explosion even though they have been cleaned For information purchase Recommended Safe Practices for the Preparation for Welding and Cutting of Containers and Piping That Have Held Hazardous Substances AWS F4 1 from the American Welding Society see address above Vent hollow castings or containers before heating cutting or welding They may explode Sparks and spatter are thrown from the welding arc Wear oil free protective garments such as leather gloves heavy shirt cuffless trousers high shoes and a cap over your hair Wear ear plugs when welding out of position or in confined places Always wear safety glasses with side shields when in a welding area Connect the work cable to the work as close to the welding area as practical Work cables connected to the building framework or other locations away from the welding area increase the possibility of the welding current passing through lifting chains crane cables
102. ger is released for comfort on long welds Place the toggle switch in the DOWN position for 2 Step operation or in the UP position for Trigger Interlock operation 2 Step Trigger 2 Step trigger operation is the most common When the gun trigger is pulled the welding power source energizes the electrode output and the wire feeder feeds wire for welding The power source and wire feeder continue welding until the trigger is released LF 72 74 SINGLE DUAL LINCOLN P Bh OPERATION Trigger Interlock Trigger Interlock operation provides for operator com fort when making long welds When the gun trigger is first pulled the welding power source energizes the output and the wire feeder feeds wire for welding The gun trigger is then released while the weld is made To stop welding the gun trigger is pulled again and when itis released the welding power source output turns off and the wire feeder stops feeding wire CAUTION If the arc goes out while welding with trigger interlock operation the elec trode output from the welding power source remains energized and the wire feeder will continue to feed wire until the gun trigger is again pulled and then released Return to Section TOC Return to Master TOC 6 WIRE FEED SPEED KNOB The large calibrated wire feed speed knob makes for easy and accurate adjustment of the wire feed speed The knob rotates 3 4 turn Turn the knob clockwise to increase the wire fee
103. he 5 screws hold ing the case Locate the two motor leads and the tach leads See Figure F 1 Apply the correct input voltage 42VAC to the unit With the trigger activated and the motor running check for 1VDC min 210HZ to 31VDC 1 75KHZ max between the black and white motor leads pins 7 and 8 6 Check for between 1 and 2 ohms of resistance between the above mentioned leads Also make sure there is at least 500k ohms of resistance between both leads and the motor shell With the trigger activated and the motor running check for 5VDC input on the black and red tach leads Check for 7 VDC to 85 VDC on the black and blue return leads For further testing on the drive motor you can use an isolated power source and apply between 1 and 31VDC to the leads If the armature voltage is not present step 5 and the motor operates normally when an isolated power source is applied step 8 Control board may be faulty FIGURE F 1 TACH LEAD LOCATION TACH BLACK BLACK WHITE LEAD LEAD TACH TACH RED BLUE LF 72 74 LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC 515 0 2 2 515 Return to Section TOC Return to Master TOC Return to Master TOC TROUBLESHOOTING AND REPAIR GAS SOLENOID TEST WARNING Service and repair should be performed by only Lincoln Electric factory trai
104. he Electrical Diagrams Section Table of Contents to locate the appropriate diagram CAUTION If for any reason you do not understand the test procedures or are unable to perform the test repairs safely con 1 888 935 3877 LF 72 74 LINCOLN F 2 tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed Call Return to Section TOC Return to Master TOC Return to Section TOC ojo O 515 9 2 818 SZ Return to Section TOC Return to Master TOC Return to Master TOC TROUBLESHOOTING amp REPAIR pe PC BOARD TROUBLESHOOTING PROCEDURES A WARNING ELECTRIC SHOCK can kill Have an electrician install and service this equipment Turn the input power OFF at the fuse box before working on equipment Do not touch electrically hot parts CAUTION Sometimes machine failures appear to be due to PC board failures These problems can sometimes be traced to poor electrical connections To avoid prob lems when troubleshooting and replacing PC boards please use the following procedure 1 Determine to the best of your technical ability that the PC board is the most likely component causing the failure symptom 2 Check for loose connections at the PC board to assure that the PC board is properly connected 3 If the problem persists replace the suspect PC board using standard practices to avoid s
105. he wire drive does not feed wire and the drive rolls do not spin The wire feeds erratically or the motor LED lights The wire continues to feed when the gun trigger is released POSSIBLE AREAS OF MISADJUSTMENT S FUNCTION PROBLEMS Power source not on Possible tripped breaker Faulty gun trigger Possible faulty control cable Wrong drive rolls installed Possible problem with gun Pressure arm or brake tension to tight Examine the contact tip for wear or proper size 1 Trigger interlock switch in wrong position 2 Gun trigger shorted or stuck RECOMMENDED COURSE OF ACTION 1 Verify the power source is on Verify power is being applied to the wire feeder Verify the circuit breaker of the wire feeder or the power source has not tripped Check to see if the gun trigger is working properly Check for cable continuity and for broken or bent pins Verify the correct drive rolls and inner wire guides are installed in the wire drive Check for sharp bends in gun liner Check gun liner The welding elec trode should slide easily through the gun Verify proper gun liner is installed 3 Adjust brake tension Adjust pressure arm see FIGURE A 6 4 Replace if necessary 5 If using wire conduit verify that the wire slides easily through the conduit 6 Perform WIRE DRIVE OTOR TEST Perform TACH EEDBACK TEST 1 Check if the 2 step trigger inter lock switch is in
106. he wire feeder feeds wire for welding The power source and wire feeder continue welding until the trigger is released Trigger Interlock Trigger Interlock operation provides for operator com fort when making long welds When the gun trigger is first pulled the welding power source energizes the output and the wire feeder feeds wire for welding The gun trigger is then released while the weld is made To stop welding the gun trigger is pulled again and when it is released the welding power source output turns off and the wire feeder stops feeding wire CAUTION If the arc goes out while welding with trigger interlock operation the elec trode output from the welding power source remains energized and the wire feeder will continue to feed wire until the gun trigger is again pulled and then released OPERATION BB 6 7 GUN RECEIVER BUSHING K1500 2 K1500 2 bushing is standard on all LF 74 s This Gun Receiver Bushing is used with Lincoln gun connectors also with Magnum 200 300 400 guns and compatible with Tweco 52 54 8 TRIGGER CONNECTOR 5 PIN AMPHENOL This is used for connecting the MIG gun trigger See Installation Section detail LF 72 74 LINCOLN Section CC 1 TABLE OF CONTENTS Section CC 1 ACCESSORIES SECTION ACGCOSSOFIGS caccia isa Rin Section CC General Options
107. hielding gas inlet Tighten the union nuts with a wrench 6 Before opening the cylinder valve turn the regulator adjusting knob counterclockwise until the adjusting spring pressure is released 7 Standing to one side open the cylinder valve slowly a fraction of a turn When the cylinder pressure gage stops moving open the valve fully 8 The flow regulator is adjustable Adjust it to the flow rate recommended for the procedure and process being used before making a weld LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC ojo O 8 5 5 0 0 12 218 cic SZ a Return to Section TOC Return to Master TOC Return to Master TOC A 16 INSTALLING ELECTRODE CONDUIT KITS A 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 Electrode conduit is used when feeding wire drums from boxes or large reels For best feeding results use the shortest conduit length possible and avoid sharp bends For Codes 11075 11076 11077 Tools required See Figure A 10a Snap Ring Pliers To install Lincoln conduit 1 Turn off power at the welding power source 2 Remove the snap ring holding the ball bushing INSTALLATION For Codes 11209 11210 11211 and above To install Lincoln conduit See Figure A 10b 1 Turn off power
108. i BALL SCREW BEARINGS v 4 Place the ball bushing housing into the wire feeder case and secure with the O ring LF 72 74 LINCOLN 5 AA 19 9 N x l N Eia N 3 5 Ju lt 3 E o 1 8 Sr gt lt 2 Cy E a L 5 5 lt tc gt lt 201 Je o 1 201 Je ISEN SOL ISe N o 1 d 201 Je ISe N o 1 d DOL o 1 d DOL noe S JOL 1295 o 1 d JOL o 1 une d nee INSTALLATION COMMON EQUIPMENT SET UPS FIGURE AA 14 GENERAL FABRICATION Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Description LF 74 Bench Model with Heavy Duty Wire Reel Stand K2426 2 035 045 0 9mm 1 2mm Drive Roll Kit 1C 3m Control Cable 1C E See welding gun literature Magnum Gun HE om 222 __48 K586 1 Deluxe Regulator for Mixed Shielding K1557 1 Ground Clamp 1802 1 Weld Power Cables Twist Mate to Lug 2 included 5 2400 1 CV 305 2 9 o gt E 2 Shielding Gas Hose 8 e z 8 e 1 1B 1D 2A 2B 3 4A 4B 5 Return to Section TOC Return to Master TOC
109. ill not start tocated on when lit 1 current exceeds 4 W Amps for an extended time 15 VDC Open COLDFEED 0 VDC Closed Located on Case Front 51 15 VDC Open 0 VDC Closed TRIGGER INTERLOCK Located on Case Front 52 Trigger Interlock does not 2STEP stop welding when the arc is broken Pull and 15 VDC in release to end the weld 2STEP position LF 72 74 Return to Section TOC Return to Section TOC EJE 5 5 Tiu 9106 es 218 mI 5 5 8 ojo Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC G 7 ELECTRICAL DIAGRAMS SCHEMATIC ENTIRE MACHINE CODE 11209 11210 11211 11227 G4617 1 LF 72 Values for CV300 Others may be different 0 VDC 0 5 8 Arc Volts 6 6 VDC 6 10 40 ArcVolts 76A 16 VOLTAGE POTENTIOVETER i n OPTIONAL Connector vests oo behind case front in P7 577 3 gt 5 576 2 gt 576 WREFEED 575 1 575A SPEED Connector located Gearbox ratio is 2 47 Motor resistance 4 CONTROL by sheet panel Motor is at electrode is 15 ohms 5 5 0 VDC MIN WFS POTENTIOMETER ae potential 56 5 VDC MAX WFS Off 0 VDC 575 p M located OCV 59 VDC 5758 si fasti Pe glastic panel On 27 7 VDC 575 562 562 4 Connector located 563 5758 5 MOTOR behind case front Located o
110. ing on this equipment Do not touch electrically hot parts Electrode conduit is used when feeding from wire drums boxes or large reels For best feeding results use the shortest conduit length possible and avoid sharp bends Tools required 1 8 Hex key wrench 5 16 Nut Driver To install Lincoln conduit 1 Turn off power at the welding power source FIGURE AA 12 MOUNTING SCREWS SECURING WIRE DRIVE PANEL Sa INCOMING D BUSHING Ea lt gt B BALL AME BUSHING ASSEMBLY Q O RING e e SET SCREW ec MOUNTING SCREWS SECURING WIRE DRIVE PANEL REMOVE 6 MOUNTING SCREWS 2 Remove the o ring holding the ball bushing assem bly to the back of the wire feeder Remove the ball bushing assembly 3 Remove the six screws securing the wire drive panel to the sheet metal housing INSTALLATION AA 17 4 Loosen the set screw on the feed plate and remove the incoming bushing FIGURE AA 12a CONDUIT CONNECTOR 5 Insert the conduit connector into the feed plate and secure with the set screw Rotate the conduit con nector so the thumb screw does not interfere with the idle arm or door 6 Mount the wire drive panel to the sheet metal hous ing with the six screws 7 Insert conduit through the sheet metal of the LF 74 and into the co
111. les rayons de l arc peuvent r agir avec les vapeurs du solvant pour produire du phosg ne gas fortement toxique ou autres produits irritants Si on utilise la machine souder comme une source de 11 Pour obtenir de plus amples renseignements sur la s ret voir courant pour soudage semi automatique ces precautions pour le porte lectrode s applicuent aussi au pistolet de soudage 2 Dans le cas de travail au dessus du niveau du sol se prot ger le code Code for safety in welding and cutting CSA Standard W 117 2 1974 contre les chutes dans le cas ou on recoit un choc Ne jamais PR CAUTIONS DE S RET POUR enrouler le c ble lectrode autour de n importe quelle partie du corps LES MACHINES A SOUDER A Un coup d arc peut tre plus s v re qu un coup de soliel donc TRANSFORMATEUR ET REDRESSEUR a Utiliser un bon masque avec un verre filtrant appropri ainsi qu un verre blanc afin de se prot ger les yeux du rayon nement de l arc et des projections quand on soude ou 1 quand on regarde l arc b Porter des v tements convenables afin de prot ger la peau de soudeur et des aides contre le rayonnement de l arc c Prot ger l autre personnel travaillant proximit au soudage l aide d crans appropri s et non inflammables Des gouttes de laitier en fusion sont mises de l arc de soudage Se prot ger avec des v tements de protection libres de l huile tels que les gants en cuir chemise pai
112. licable OSHA PEL and ACGIH limits Do not weld in locations near chlorinated hydrocarbon vapors coming from degreasing cleaning or spraying operations The heat and rays of the arc can react with solvent vapors to form phosgene a highly toxic gas and other irritating prod ucts Shielding gases used for arc welding can displace air and cause injury or death Always use enough ventilation especially in confined areas to insure breathing air is safe Read and understand the manufacturer s instructions for this equipment and the consumables to be used including the material safety data sheet MSDS and follow your employer s safety practices MSDS forms are available from your welding distributor or from the manufacturer Also see item 1 b AUG 06 Return to Master TOC Return to Master TOC 2 D 8 Return to Master TOC SAFETY WELDING SPARKS gt cause fire or explosion 6 a Remove fire hazards from the welding area If this is not possible cover them to prevent the welding sparks from starting a fire Remember that welding sparks and hot materials from welding can easily go through small cracks and openings to adjacent areas Avoid welding near hydraulic lines Have a fire extinguisher readily available Where compressed gases are to be used at the job site special precautions should be used to prevent hazardous situations Re
113. lve outlet 4 Attach the flow regulator to the cylinder valve and tighten the union nut s securely with a wrench Note if connecting to 100 CO cylinder insert reg ulator adapter between regulator and cylinder valve If adapter is equipped with a plastic washer be sure it is seated for connection to the CO cylinder 5 Attach one end of the inlet hose to the outlet fitting of the flow regulator Attach the other end to the welding system shielding gas inlet Tighten the union nuts with a wrench INSTALLATION AA 14 6 Before opening the cylinder valve turn the regulator adjusting knob counterclockwise until the adjusting spring pressure is released 7 Standing to one side open the cylinder valve slowly a fraction of a turn When the cylinder pressure gage stops moving open the valve fully 8 The flow regulator is adjustable Adjust it to the flow rate recommended for the procedure and process being used before making a weld LF 72 74 LINCOLN B Return to Section TOC Return to Master TOC Return to Section TOC O10 O JE 5 2 9 2 2 2 Return to Section TOC Return to Master TOC Return to Master TOC AA 15 WIRE REEL LOADING A WARNING Keep hands hair clothing and tools away from rotating equipment Do not wear gloves when threading wire or changing wire spool Only qualified personnel should install use or service this equipment Loadi
114. m 3 32 2 4mm Drive Roll Kits Aluminum Wire Includes 4 polished U groove drive rolls outer wire guide and inner wire guide KP1507 035A 035 0 9 mm 040 1 0mm 3 64 1 2mm 1 16 1 6mm DRIVE ROLLS INNER WIRE GUIDE LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC O 5 5 5 2 2 2 2 Return to Section TOC Return to Master TOC Return to Master TOC AA 10 WELDING GUNS TORCHES AND ACCES SORIES GUN RECEIVER BUSHING The LF 74 wire feeder comes with a K1500 2 gun receiver bushing MAGNUM GUN AND CABLE ASSEMBLIES The LF 74 wire feeder model will accept a number of optional gun and cable assemblies An example of installing the Gun and Cable is shown in Figure AA 3 with a 15 ft 4 6m long Magnum 400 gun and cable 1 Turn off power at the welding power source 2 Unscrew Thumb screw on Wire Drive Unit until tip of screw no longer protrudes into gun bushing hole as seen from the front of machine FIGURE AA 3 TRIGGER RECEPTACLE INSTALLATION LF 74 BASE MODEL AA 10 3 Fully insert the gun cable connector end into the gun receiver bushing and gently tighten the thumb screw as show in Figure AA 3 below 4 Connect the gun trigger connector to the trigger receptacle Make sure that the key ways are aligned and insert GUN RECEIVER BUSHING HE INTERCHANGABLE
115. n lt lt case back 551 lt 7 measures 550 8 w To Power Source Electrode Connection 21 ohms s 5 1 6V 50 IPM SOENOD 30 6V 800 IPM 2 TRIGGER INPUT 556 8 554 _ FB TRIGGER CONNECTOR D E n E 5528 Located on internal panel Start Up Located on Case Front On power up the LF 72 will light the motor thermal LED for 0 5 seconds If the feeder is powered up with the Lights ipli d trigger depressed welding will not start 4 4 until the trigger is released and then Timer Board Summary Case Front pio UM P gen Has potentiometers for burnback and postflow Preflow fixed at 30msec 15 VDC Open L1 Burnback range is 0 to 0 25 sec Located on ARC CURRENT J Postflow range is 0 25 to 10 sec Case Front Receives Gas Flow Enable signal zawac Outputs 100 msec pulses to turn Gas Flow On Flow Off 15 0 VDC Closed SENSE 20 OHM OUTPUT ENABLED HIGH IMPEDANCE OUTPUT DISABLED TRIGGER INTERLOCK Located on 589 Case Front 587 52 38VDC at Trigger Interlock does not 42VAC input NOT USED NOT USED 2STEP stop welding when the with control arc is broken Pull and board release to end the weld disconnected position 60VDC with control board connected Control Board Summary Has on board power supply Receives switch signals from T
116. n to Section TOC Return to Master TOC Return to Master TOC A 8 NOTES A 8 ANALOG MILLER CONTROL CABLE ADAPTER K2335 1 This Lincoln Electric wire feeder may be mounted to a limit ed number of Miller Electric power sources The Miller power source must have the amphenol pin definition shown in the table below for proper operation of the wire feeder Operation of Lincoln wire feeders on Miller power sources may result in lack of high speeds or reduce pull force on high wire feed speeds Maximum wire feed speed for the LF 72 operating on a Miller power source is approximately 720ipm Be sure the Miller power source provides 24 VAC to the wire feeder and has overcurrent protection of no more than 15 amps The power source must not exceed 113VDC peak POWER SOURCE WIRE FEEDER JO OA 10 OB HO NO OL Oc Function i Function A 24 VAC to feeder 42 VAC feeder Welding Output Control B Welding Output Control Welding Output Control E Remote Voltage Control supply from power source G Remote Voltage Control supply from power source 0 10VDC from feeder for remote control Remote Voltage Control control signal from feeder or remote Current feedback to feeder Reserved for future use Scaled 0 10V 1 V 100 amps Ref ced to pin D d eferen G 24 VAC common K 42 VAC to feeder N H Arc Voltage feedback to feeder L Reserved for future use Scaled 0 10V 1 V 10 Ar
117. ncoln Electric Service Department for electrical troubleshooting assistance before you proceed Call 1 888 935 3877 TEST DESCRIPTION This procedure will aid the technician in the removal and replacement of either the drive motor or the gear box MATERIALS NEEDED 5 16 in nut driver 7 16 in socket wrench and extension 3 4 in wrench Phillips head screw driver Pliers LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 8 e Return to Section TOC Return to Master TOC 2 9 o gt 2 TROUBLESHOOTING AND REPAIR FORM WIRE DRIVE MOTOR AND GEAR BOX REMOVAL AND REPLACEMENT PROCEDURE Continued Figure F 7 Wire Drive Motor s MOUNTING SCREWS MOUNTING BOLTS SECURING WIRE DRIVE PANEL INCOMING U Hu ae BUSHING BALL 1 BUSHING ASSEMBLY gt N Q O RING e N SET SCREW 27 cai MOUNTING SCREWS SECURING WIRE DRIVE PANEL REMOVE 6 MOUNTING SCREWS PROCEDURE 6 Using the 3 4 inch wrench remove the electrode cable from the connector 1 Remove th input power from the block LF72 LF72 unit 7 Remove the tach and motor leads by 2 Remove the gun from the unit disconnecting the P10 connector See 3 Using the 5
118. nduit connector Secure with the thumb screw LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC ojo O 515 0 9 2 2 SZ Return to Section TOC Return to Master TOC Return to Master TOC AA 18 ALUMINUM WIRE PREPARATIONS A 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 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 FIGURE AA 12b BALL BUSHING ASSEMBLY 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 INSTALLATION AA 18 FIGURE AA 13 HOUSING disc gt 2
119. ned personnel Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty For your safety and to avoid electrical shock please observe all safety notes and pre cautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to per form the test repairs safely contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed Call 1 888 935 3877 TEST DESCRIPTION This test will determine if the gas solenoid is receiving the correct voltage and if the solenoid is functional MATERIALS NEEDED 5 16 in nut driver 12 VDC Q 1 amp power source Volt Ohmmeter LF 72 74 LINCOLN 5 F 9 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 Return to Section TOC Return to Master TOC 2 D 8 3 TROUBLESHOOTING AND REPAIR 640 GAS SOLENOID TEST continued FIGURE F 2 GAS SOLENOID SQ GAS SOLENOID as TEST PROCEDURE 1 Remove the input power from the LF72 LF74 unit 2 Using the 5 16 nut driver remove the 5 screws holding the cover 3 Locate the gas solenoid FIG F 2 on the back of the feeder 4 Apply the correct 42VAC input voltage to the unit 5 While pressing the gas purge
120. ng 10 to 15 Ib 4 5 6 8kg Spools A K468 spindle adapter is required for loading 2 wide spools on 2 51mm spindles Use a K468 1 spindle adapter for loading 2 1 2 64mm wide spools See figure AA 9 and figure AA 10 1 Squeeze the release bar on the retaining collar and remove it from the spindle 2 Place the spindle adapter on the spindle aligning the spindle brake pin with the hole in the adapter 3 Place the spool on the spindle and align the adapter brake tab with one of the holes in the back side of the spool An indicator mark on the end of the spin dle shows the orientation of the brake tab Be cer tain the wire feeds off of the spool in the proper direction 4 Re install the retaining collar Make sure that the release bar snaps out and that the retaining collar fully engages the groove on the spindle FIGURE AA 9 Adapter Spindle Placement The wire reel stand provides two mounting locations for the spindle Each mounting location consists of a tube in the center of the mast and locating slots Loading 16 to 44 Ib 7 3 20kg Spools See figure AA 8 1 Squeeze the release bar on the retaining collar and remove it from the spindle 2 Place the spool on the spindle aligning the spindle brake pin with one of the holes in the back side of the spool An indicator mark on the end of the spin dle shows the orientation of the brake holding pin Be certain the wire feeds off of the spool in the prop
121. nsion Add cables to extend up to 110 30m 5A ift Bai 5 OO O 7 O 3 3 3 5 7 1 2 A C D A C 7 A 10 Return to Section TOC Return to Master TOC LF 72 74 LINCOLN 5 Section BB 1 TABLE OF CONTENTS Section BB 1 OPERATION SECTION gt SICUBI IERI NM IE Section BB 5 Salei Precautions el adc ed ade BB 2 Graphie Sube BB 2 Common Welding Abbreviations 2 Product Description Deed det BB 3 Recommended Processes and Required Equipment BB 3 Front Panel Controls and Connections BB 4 T 1 Wire Feed Speed KN OD reitera pod eder BB 5 2 Remote Voltage Control Kit Optional BB 5 3 Burnback and Timer BB 5 4 Thermal LED Motor BB 5 p 5 Gold Feed Gas Purge SWIECh 5 2 Step Trigger Interlock BB 6 7 Gun Receiver BUSHING rete BB 6 8 Trigger Connector 5 Pin BB 6 2 D
122. oes NOT operate on 115 VAC NOT USED NOT USED NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual Values for CV300 Others may be different 5 0 VDC 0 5 8 Arc Volts D th 6 6 VDC 10 40 ArcVolts e o REMOTE 75 1 75 CONTROL u 16 ww VOLTAGE 8 ee POTENTIOMETER 4 3 n OPTIONAL Connector located rem behind case front P7 HN O ac T cc 577A WRE FEED 576 2 5764 Gearbox 16 2 47 CONTROL Connector located earbox ratio by sheet panel Motor is at electrode Motor resistance gt 4 gt WEE POTENTIOMETER i 5 VDC MIN WFS ica 575 Motor is located 26 59 VDC 5758 L4 behind PS 563 3 glastic panel On 7 7 VDC 575c 562 562 4 lt Connector located ES x 563 5758 54 MOTOR behind case front Located on Coil case back measures To Power Source Electrode Connection 21 ohms GAS 1 6V 50 IPM SOLENOID 30 6V 6 800 IPM 5528 TRIGGER Qo INPUT e 556 Plug for future Located behind 554 TRIGGER c run in kit P9 front panel lt CONNECTOR Eg n Bla E 9106 alz 8 Located Start Up Case Front On power up the LF 72 will light the THERMALLED 5 motor thermal LED for 0 5 seconds If the feeder is powered up with the J 5 VDC 6 Lights when motor cc trigger depressed welding w
123. om sticking to the weld at the end of a weld and helps to condition the wire for the next weld OPERATION BB 5 To set the burnback time adjust the knob to approxi mately 0 03 seconds and then decrease or increase the time as desired DEBES Postflow Timer The postflow timer range is OFF to 10 seconds Postflow is the time from when the power source out put turns OFF until the postflow timer expires Use postflow to protect the weld while the weld cools 4 THERMAL LED MOTOR OVERLOAD The thermal light illuminates when the wire drive motor draws too much current If the thermal light illu minates the wire drive will automatically shutdown for up to 30 seconds to allow the motor to cool To start welding again release the gun trigger inspect the gun cable liner and conduit Clean and make repairs as necessary Start welding again when the problem has been safely resolved For best results keep the gun cable and conduit as straight as possible Perform regular maintenance and cleaning on the gun liner conduit and gun Always use quality electrode such as L 50 or L 56 from Lincoln Electric 5 COLD FEED GAS PURGE SWITCH Cold Feed and Gas Purge are combined into a single spring centered toggle switch To activate Cold Feeding hold the switch in the UP position The wire drive will feed electrode but neither the power source nor the gas solenoid will be ene
124. ontainers which have held flammable material ARC RAYS can burn 4 Wear eye ear and body protection Observe additional guidelines detailed in the begin ning of this manual OPERATION BB 2 GRAPHIC SYMBOLS THAT APPEAR ON THIS MACHINE OR IN THIS MANUAL COLD FEED POSITIVE OUTPUT NEGATIVE OUTPUT PROTECTIVE GROUND WARNING OR CAUTION DANGEROUS VOLTAGE 3 7 e y SHOCK HAZARD WELDING FUMES EXPLOSION GAS INPUT WORK CONNECTION COMMON WELDING ABBREVIATIONS WFS Wire Feed Speed CV Constant Voltage GMAW MIG Gas Metal Arc Welding FCAW Innershield or Outershield Flux Core Arc Welding LF 72 74 LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 515 9 5 2 2 2 Return to Section TOC Return to Master TOC BB 3 PRODUCT DESCRIPTION General Physical Description The LF 74 is optimized for GMAW and FCAW welding The powerful 4 roll MaxTrac drive heavy duty enclo sure 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 performance motor gearbox A heavy duty hinged door opens easily which provides an ample amount of room for assembling pre cision drive components and the welding gun MaxTrac technology delivers great feeding because Patent
125. ools on 2 in 51 mm spindles K363P Readi Reel Adapter for mounting Includes Readi Reel spool 23 30 Ib 10 4 13 6 kg reels to 2 adapter Spool of electrode in 51 mm spindles not included K438 Readi Reel Adapter for mounting Includes Readi Reel spool 50 60 Ib 22 7 27 2 kg reels to adapter Spool of electrode 2 in 51 mm spindles For use not included with Heavy Duty Bench models Coil Adapter for mounting 50 60 K1504 1 Ib 22 7 27 2 kg coils to 2 in 51 Includes 50 60 Ib 22 7 mm spindles 27 2 kg coil adapter For use with heavy Duty Bench LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 Return to Section TOC Return to Master TOC 2 D 8 ACCESSORIES OPTIONAL KITS Includes Cover backing K1634 1 Plastic Wire Cover for 30 44 Ib plate wire conduit incoming 13 6 20 0 kg Wire packages bushing for 025 1 16 0 6 For use with Standard Duty 1 6 mm wire incoming bush Bench Models and Heavy Duty ing for 1 16 1 8 1 6 3 2 Bench Models mm wire thumb screw mounting hardware and hex key K1634 2 Plastic Wire Cover for up to 60 Ib 27 2kg Wire packages For use with Heavy Duty Bench Models K659 1 Gas Guard Regulator Includes Gas Guard Regulator and adjustment key Includes Gas Regula
126. or other alternate circuits This can create fire hazards or overheat lifting chains or cables until they fail 6 h Also see item 1 c LINCOLN ew damaged 7 a Use only compressed gas cylinders containing the correct shielding gas for the process used and properly operating regulators designed for the gas and pressure used All hoses fittings etc should be suitable for the application and maintained in good condition Always keep cylinders in an upright position securely chained to an undercarriage or fixed support Cylinders should be located Away from areas where they may be struck or subjected to physical damage A safe distance from arc welding or cutting operations and any other source of heat sparks or flame Never allow the electrode electrode holder or any other electrically hot parts to touch a cylinder Keep your head and face away from the cylinder valve outlet when opening the cylinder valve Valve protection caps should always be in place and hand tight except when the cylinder is in use or connected for use Read and follow the instructions on compressed gas cylinders associated equipment and CGA publication Precautions for Safe Handling of Compressed Gases in Oylinders available from the Compressed Gas Association 1235 Jefferson Davis Highway Arlington VA 22202 FOR ELECTRICALLY powered equipment 8 a Turn off input power using the di
127. ow On Gas TE tb 5 VDC Lights when motor when lit current exceeds 18 1W 3 75 Amps for an extended time 15 VDC Open FEED through 0 VDC Closed toroid 2 558 Case Front times 515A 515 51 559 15 VDC Open GAS PURGE 0 VDC Closed TRIGGER INTERLOCK Located on 589 Case Front 587 52 Trigger Interlock does not 2STEP stop welding when the arc is broken Pull and 15 VDC in release to end the weld 25 position Start Up On power up the LF 72 will light the motor thermal LED for 0 5 seconds If the feeder is powered up with the trigger depressed welding will not start until the trigger is released and then depressed again Notes The WFS range of the LF 72 is 50 800 ipm Control Board Summary Has on board power supply Receives switch signals from Trigger Cold Feed Gas Purge Trigger nterlock Reads WFS potentiometer Communicates with optional timer kit to control burnback postflow Controls motor speed with PWM Turns Gas Solenoid on off Reads the motor tachometer Monitors motor current lights yellow thermal LED if over 3 75 amps for an extended time period LED remains lit for 30 60 seconds to allow motor cool Does NOT support Run in at this time Operates on 24 42 VAC Maximum WFS and or maximum pull force may be less when operating at 24 VAC Does NOT operate on 115 VAC NOTE This diagram is for reference only It may not be accurate for
128. 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 accurate drive roll alignment Patent pending dual spring pressure arms have sen sitivity 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 tar gets operators performing GMAW or FCAW welding using consumables on spools The high torque model features high ratio gearing for feeding larger diameter FCAW or GMAW wires All models use a
129. positive The voltage should be 59VDC If you are only reading 38VDC the control circuit is open Check the wiring and the connections back to your control board LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 8 Return to Section TOC Return to Master TOC 2 9 o gt gt F 13 TROUBLESHOOTING AND REPAIR WIRE SPEED POTENTIOMETER TEST WARNING Service and repair should be performed by only Lincoln Electric factory trained personnel Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty For your safety and to avoid electrical shock please observe all safety notes and pre cautions detailed throughout this manual If for any reason you do not understand the test procedures or are unable to per form the test repairs safely contact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed Call 1 888 935 3877 TEST DESCRIPTION This test will help determine if the wire speed potentiometer is receiving and sending the correct voltages MATERIALS NEEDED 5 16 in nut driver 42VAC power supply Volt Ohmmeter LF 72 74 LINCOLN 5 F 13 TROUBLESHOOTING AND REPAIR WIRE SPEED POTENTIOMETER TEST Continued Figure
130. pple set screw and hex key wrench Includes Gun receiver bush ing with hose nipple set screw and hex key wrench Includes Gun receiver bush ing with hose nipple set screw and hex key wrench Includes Gun receiver bush ing with hose nipple 4 guide tubes set screw and hex key wrench LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC LE 8 Return to Section TOC Return to Master TOC 2 D 8 idis ACCESSORIES OPTIONAL KITS Gun Receiver Bushing D Lincoln Includes Gun receiver bush Fast Mate guns ing with trigger connector K466 2 Magnum 200 300 400 to K1500 2 Includes Gun adapter cotter Adapter pin hex key wrench wrench K613 7 Magnum 550 to K1500 3 Adapter Includes Trigger adapter gun Lincoln Conduit adapter and hex key wrench K1546 1 Incoming Bushing for Lincoln Includes Incoming bushing Conduit 025 1 16 0 6 1 6mm and hex key wrench wire K1546 2 Incoming Bushing for Lincoln Includes Incoming bushing Conduit 1 16 1 8 1 6 3 2 mm and hex key wrench wire K435 Spindle Adapter for mounting 14 Includes Spindle Adapter Ib 6 4 kg Innershield Coils on 2 made from 2 coil retainers in 51 mm spindles Electrode not included K468 Spindle Adapter for mounting 8in Includes Spindle Adapter 203mm diameter sp
131. r le porte lectrode la pince de masse le c ble de soudage et la machine souder en bon et s r tat defonc tionnement d Ne jamais plonger le porte lectrode dans l eau pour le refroidir Ne jamais toucher simultan ment les parties sous tension des porte lectrodes connect s deux machines souder parce que la tension entre les deux pinces peut tre le total de la tension vide des deux machines pr venir tout risque d incendie d aux tincelles Quand on ne soude pas poser la pince une endroit isol de la masse Un court circuit accidental peut provoquer un chauffement et un risque d incendie S assurer que la masse est connect e le plus pr s possible de la zone de travail qu il est pratique de le faire Si on place la masse sur la charpente de la construction ou d autres endroits loign s de la zone de travail on augmente le risque de voir passer le courant de soudage par les chaines de levage c bles de grue ou autres circuits Cela peut provoquer des risques d incendie ou d echauffement des chaines et des c bles jusqu ce qu ils se rompent Assurer une ventilation suffisante dans la zone de soudage Ceci est particuli rement important pour le soudage de t les galvanis es plomb es ou cadmi es ou tout autre m tal qui produit des fume s toxiques Ne pas souder en pr sence de vapeurs de chlore provenant d op rations de d graissage nettoyage ou pistolage La chaleur ou
132. rgized Adjust the speed of cold feeding by rotat ing the WFS knob Cold feeding or cold inching the electrode is useful for thread ing the electrode through the gun COLD FEED 5 GAS PURGE Hold the toggle switch the DOWN posi tion to activate Gas Purge and let the shielding gas flow The gas solenoid valve will energize but neither the power source output nor the drive motor will be turned on The Gas Purge switch is useful for setting the proper flow rate of shielding gas Flow meters should always be adjusted while the shielding gas is flowing LF 72 74 LINCOLN B Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 Return to Section TOC Return to Master TOC 2 D 8 3 6 6 2 STEP TRIGGER INTERLOCK SWITCH The 2 Step Trigger Interlock switch changes the function of the gun trigger 2 Step trigger operation turns welding on and off in direct response to the trigger Trigger Interlock operation allows welding to continue when the trigger is released for comfort on long welds Place the toggle switch in the DOWN position for 2 Step operation or in the UP position for Trigger Interlock operation 2 Step Trigger 2 Step trigger operation is the most common When the gun trigger is pulled the welding power source energizes the electrode output and t
133. rigger Cold Feed Gas Purge Trigger Interlock Reads WFS potentiometer Communicates with optional timer kit to control burnback postflow Controls motor speed with PWM Turns Gas Solenoid on off Monitors motor current lights yellow thermal LED if over 3 75 amps for an extended time period LED remains lit for 30 60 seconds to allow motor to cool Does NOT support Run in at this time Operates 24 42 VAC Maximum WFS and or maximum pull force may be less when operating at 24 VAC Does NOT operate on 115 VAC NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual LINCOLN LF 72 74 Return to Section TOC Return to Master TOC Return to Section TOC eje 5 5 9106 es 81 9 5 8 ojo Return to Section TOC Return to Master TOC Return to Master TOC G 8 ELECTRICAL DIAGRAMS SCHEMATIC ENTIRE MACHINE CODE 11290 11291 11292 11293 G4617 2 LF 72 Off 0 VDC OCV 59 VDC 27 7 VDC Located on 7 Coil case back measures 21 ohms GAS SOLENOID 552 5528 Located on Sheet Panel 42 Leads Pass through toroid 2 times 112 gt 1 Located on Case Back Values for CV305 Others may be different 0 VDC 6 0 5 8 Arc Volts 6 6 VDC 10 40 ArcVolts SENSE QNO 75 75
134. rovides 24 VAC to the wire feeder and has overcurrent protection of no more than 15 amps The power source must not exceed 113VDC peak Return to Section TOC Return to Master TOC Operation of Lincoln wire feeders on Miller power sources may result in lack of high wire feed speeds or reduced pull force at high wire feed speeds Approximate maximum WFS for Lincoln wire feeders operating with 24 VAC WIRE FEEDER Return to Section TOC Return to Master TOC HO NO OL Oc GO OMOD Pin Function i Function A 24 VAC to feeder 42 feeder D Welding Output Control Welding Output Control C Welding Output Control B E Remote Voltage Control supply from power source D Remote control common G Remote Voltage Control supply from E 0 10VDC from feeder for remote control Remote Voltage Control control signal from 515 0 9 2 218 SZ feeder or remote Current feedback to feeder J Reserved for future use Scaled 0 10V 1 V 100 amps Referenced to pin D G 24 VAC common K 42 VAC to feeder H Arc Voltage feedback to feeder L Reserved for future use Scaled 0 10V 1 V 10 Arc volts Referenced to pin D N Electrode voltage to power source 67 Miller is a registered trademark not owned or licensed by The Lincoln Electric Company LF 72 74 LINCOLN Return to Section TOC Return to
135. rsonnel should perform this installation Turn off the input power to the power source at the disconnect switch or fuse box before working on this equipment Turn off the input power to any other equipment connected to the welding system at the disconnect switch or fuse box before working on this equipment Return to Section TOC Return to Master TOC Do not touch electrically hot parts WELD CABLE SIZES Table A 1 has the copper cable sizes recommended for different currents and duty cycles Lengths stipulated are the distance from the welder to work and back to the welder again Cable sizes are increased for greater lengths primarily for the purpose of minimizing voltage in the welding circuit Return to Section TOC Return to Master TOC TABLE A 1 RECOMMENDED CABLE SIZES RUBBER COVERED COPPER RATED 75 C CABLE SIZES FOR COMBINED LENGTHS OF ELECTRODE AND WORK CABLES Percent 0 to 50 Ft 50 to 100Ft 100 to 150 Ft 150 to 200 Ft 200 to 250 Ft Duty Amperes 0 to 15 m 15 to 31 m 31 to 48 m 48 to 61 m 61 to 76 m ojo O 515 0 9 2 2 SZ Tabled values are for operation at ambient temperatures of 40 C and below Applications above 40 C may require cables larger than recommended or cables rated higher than 75 C Return to Section TOC Return to Master TOC LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section
136. s K2426 Extra Torque Model with Heavy Duty Wire Stand LF 72 74 LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC ojo O 5 5 0 9 0 2 2 SZ Return to Section TOC Return to Master TOC Return to Master TOC AA 3 SAFETY PRECAUTION ELECTRIC SHOCK can kill Turn the input power OFF at the welding power source before instal lation or changing drive rolls and or guides 0 Do not touch electrically live parts When inching with the gun trigger electrode and drive mechanism are hot to work and ground and could remain energized several sec onds 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 main tenance work LOCATION The LF 74 may be placed on a bench mounted on top of a welding power source or assembled to an appro priate boom Place the LF 74 in a clean and dry location Do not stack the LF 74 1 4 20 THREADS 4 PLACES 5 16 18 THREADS 4 PLACES INSTALLATION 5 8 16 THREADS 4 PLACES AA 3 MOUNTING For location and size LF 74 Bench Model Rear Mounting Holes See Figure AA 1 and for Bottom Mounting Holes See Figure AA 2 FIGURE AA 1 10 15 10 77 FIGURE AA 2 2 10 6 00 10 30 MOUNTING FEET SECURED WITH
137. s counter clockwise to unscrew them from the feed plate 4 Rotate the triangular lock and remove the drive UNLOCKED LOCKED POSITION POSITION rolls FIGURE A 4 5 Remove the inner wire guide 6 Insert the new inner wire guide groove side out over the two locating pins in the feed plate 7 Install a drive roll on each hub assembly secure with the triangular lock 8 Install the outer wire guide by aligning it with the pins and tightening the knurled thumbscrews 9 Close the idle arm and engage the idle roll pressure arm Adjust the pressure appropriately INSTALLATION CONNECTOR BLOCK WIRE DRIVE CONFIGURATION See Figure A 5 Changing the Gun Receiver Bushing WARNING ELECTRIC SHOCK can kill Turn the input power OFF at the dis connect switch or fuse box before attempting to connect or disconnect input power lines output cables or control cables Only qualified personnel should perform this installation Tools required 1 4 hex key wrench Note Some gun bushings do not require the use of the thumb screw 1 Turn power off at the welding power source 2 Remove the welding wire from the wire drive 3 Remove the thumb screw from the wire drive 4 Remove the welding gun from the wire drive 5 Loosen the socket head cap screw that holds the connector bar against the gun bushing Important Do not attempt to completely remove the socket head cap screw 6 Remove the outer wire guide and
138. scale and mounting hardware Includes Panel and harness 94 K2330 1 Timer Kit for adjusting burnback and AE postflow times judice di Includes Wire Reel Stand for K2328 1 Standard Duty Wire Reel Stand up to 44 Ibs 20 kg spools Spindle and mounting hard ware K2331 1 Lift Bail Kit Includes Insulated lift bail and hardware K2332 1 Swivel Kit Includes Swivel adapter and for use with Standard Duty Bench mounting hardware for attach Models ing to a power source lift bale Includes Coaxial weld cable of length xx Ends of the K1796 xx Co Axial Power Cable weld cable have lug connec tions Use for Pulse or STT welding Includes Twist Mate to Lug 2 0 cable 14 1 2m long with K1803 1 Work and Feeder Cables Ground Clamp and Twist Package Mate to Lug 2 0 Cable 9 2 7m long K1840 xx Weld Power Cable Twist Mate to Includes Twist Mate to Lug Lug 1 0 cable of length xx Includes Twist Mate to Twist Mate 1 0 Cable for 25 7 6m K1844 xx Weld Power Cable cables Twist Mate to Twist Mate Includes Twist Mate to Twist Mate 2 0 Cable for 50 15 2m cables Includes Lug to Lug 3 0 Cable of length xx for K1842 xx Weld Power Cable Lug to Lug lengths up to 60 18 3m Lug to Lug 4 0 Cable of length xx for lengths greater than 60 18 3m LF 72 74 LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC O 5 5
139. sconnect switch at the fuse box before working on the equipment Install equipment in accordance with the U S National Electrical Code all local codes and the manufacturer s recommendations Ground the equipment in accordance with the U S National Electrical Code and the manufacturer s recommendations Mar 95 Return to Master TOC Return to Master TOC 2 D 8 E Return to Master TOC PR CAUTIONS DE S RET SAFETY zones l on pique le laitier Pour votre propre protection lire et observer toutes les instructions 6 Eloigner les mat riaux inflammables ou les recouvrir afin de et les pr cautions de s ret specifiques qui parraissent dans ce manuel aussi bien que les pr cautions de s ret g n rales suiv antes S ret Pour Soudage A L Arc 1 Protegez vous contre la secousse lectrique Les circuits l lectrode et la pi ce sont sous tension quand la machine souder est en marche Eviter toujours tout contact entre les parties sous tension et la peau nue ou les v tements mouill s Porter des gants secs et sans trous pour isoler les mains Faire tr s attention de bien s isoler de la masse quand on soude dans des endroits humides ou sur un plancher met allique ou des grilles metalliques principalement dans les positions assis ou couch pour lesquelles une grande partie du corps peut tre en contact avec la masse Mainteni
140. sse pan talons sans revers et chaussures montantes Toujours porter des lunettes de s curit dans la zone de soudage Utiliser des lunettes avec crans lateraux dans les LINCOLN Relier la terre le chassis du poste conformement au code de l lectricit et aux recommendations du fabricant Le dispositif de montage ou la piece souder doit tre branch une bonne mise la terre Autant que possible l installation et l entretien du poste seront effectu s par un lectricien qualifi Avant de faires des travaux l interieur de poste la debranch er l interrupteur la boite de fusibles Garder tous les couvercles et dispositifs de s ret leur place Mar 93 RETURN TO MAIN MENU MASTER TABLE OF CONTENTS FOR ALL SECTIONS Safety wees eee i iv Installation EF 72 ee eee eee ERE Section A Installation LF 74 IRE RT ERE Section AA Operation LF 72 2 ni Rx ERR Raus Ro me Section B Operation LE 74 2 rex mmm eee Section BB Accessories LF 72 Section C Accessories LF 74 2 Section CC Maintenance 72 2 2 42 Section D Maintenance LF 74 Section DD Theory of Operation Section E Troubleshooting and Repair
141. sters 2 Heavy Duty Bench Models Fixed Casters brackets and mounting hardware Insulated Lift Bail Includes Insulated Lift Bail for use with Heavy Duty Bench and mounting hardware Models LF 72 74 LINCOLN 5 CC 6 2 E RE DOL 01 DOL Je1se N 901 Je1Se N 01 201 ISEW 01 CC 6 DOL uonoeg DOL uonoeg DOL uunjeH 901 Section DD 1 TABLE OF CONTENTS Section DD 1 MAINTENANCE SECTION 5 E gt Section DD E 5 Safety Precautions DD 2 Routine aiii 2 Periodic Maintenance 2 Calibration 2 Major Component Locations DD 4 Return to Master TOC 2 D 2 8 5 Return to Master TOC POWER FEED 10M SINGLE DUAL LINCOLN 5 Return to Section TOC Return to Master TOC DD 2 MAINTENANCE Safety Precautions A WARNING ELEC
142. t RECOMMENDED PROCESSES GMAW 023 1 16 0 6 1 6 mm steel electrodes FCAW 035 5 64 0 9 2 0mm cored electrodes a OPERATION ES PROCESS LIMITATIONS Rated for up to 1 16 1 6 mm solid electrode and 5 64 2 0 mm cored electrode e 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 Ib 20 kg 12 inch 300mm diame ter 4 inch 100mm For K2327 3 Bench model heavy duty Maximum spool size 60 Ib 27 2 kg REQUIRED EQUIPMENT 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 LF 72 74 LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 8 e Return to
143. tatic electrical damage and electrical shock Read the warning inside the static resistant bag and perform the following procedures PC board can be damaged by static electricity Remove your body s static charge before opening the static shielding bag Wear an anti static wrist strap For safety use a 1 Meg ohm resistive cord connected to a grounded part of the equipment frame ATTENTION Static Sensitive Devices Handle only at Static Safe Workstations If you don t have a wrist strap touch an un painted grounded part of the equipment frame Keep touching the frame to prevent static build up Be sure not to touch any electrically live parts at the same time Tools which come in contact with the PC board must be either conductive anti static or static dissipative Remove the PC board from the static shielding bag and place it directly into the equipment Don t set the PC board on or near paper plastic or cloth which could have a static charge If the PC board can t be installed immediately put it back in the static shield ing bag If the PC board uses protective shorting jumpers don t remove them until installation is complete If you return a PC board to The Lincoln Electric Company for credit it must be in the static shielding bag This will prevent further damage and allow prop er failure analysis 4 Test the machine to determine if the failure symptom has been corrected by the
144. the TRIGGER INTERLOCK position 2 Verify operation of the gun trig ger Check for shorted trigger leads CAUTION If for any reason you do not understand the test procedures or are unable to perform the test repairs safely con tact the Lincoln Electric Service Department at 1 888 935 3877 for electrical troubleshooting assistance before you proceed LF 72 74 SINGLE DUAL LINCOLN Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC 8 8 Return to Section TOC Return to Master TOC 2 9 o gt E tc LF 72 74 p TROUBLESHOOTING amp REPAIR ps Observe Safety Guidelines detailed in the beginning of this manual PROBLEMS SYMPTOMS POSSIBLE AREAS OF MISADJUSTMENT S RECOMMENDED COURSE OF ACTION FUNCTION PROBLEMS Continued No shielding gas 1 No gas supply or gas supply interrupted 2 Solenoid not functioning 1 Verify cylinder is not empty and is turned on Check the hose for cuts or kinks Make sure it is not crushed Verify the hose is connected to the gun bushing or welding gun 2 Perform the GAS SOLENOID TEST Variable or hunting arc 1 Bad contact tip 2 Possible loose connection in current carrying cables 3 Set up not correct 4 Problem with shielding gas 1 Check for proper size contact tip Make sure tip is not worn and is free of
145. tor for 3000290 Adjustable Gas Regulator Mixed Gases and 10 3 0m Hose Includes Deluxe Gas K586 1 Deluxe Adjustable Gas Regulator Regulator for Mixed Gases Adapter for CO2 and 10 3 0m Hose K1524 3 Heavy Duty Universal Wire Reel Includes Heavy Duty Wire Stand For spools up to 60 Ib Reel Stand 27 2kg 4 Wheeled Wire Feeder Includes Undercarriage with K163 Undercarriage For use with 8 208mm rear wheels 4 Standard Duty Bench Models and 102mm casters Heavy Duty Bench Models K1557 1 Swivel Platform for use with Includes Swivel Platform and Heavy Duty Bench Models Tray K1556 1 Light Duty Caster Kit for use with Includes 2 Swivel Casters 2 Heavy Duty Bench Models Fixed Casters brackets and mounting hardware Insulated Lift Bail Includes Insulated Lift Bail for use with Heavy Duty Bench and mounting hardware Models LF 72 74 LINCOLN 5 C 6 2 E RE DOL 01 DOL Je1se N 901 Je1Se N 01 201 ISEW 01 C 6 DOL uonoeg DOL uonoeg DOL uunjeH 901 Section D 1 TABLE OF CONTENTS Section D 1 MAINTENANCE SECTION cuadscveactaancuesceucavdsacucaadsescectdaacuecdeias Section D Return to Master TOC Salety Precautions debere cree NN up Sa EUREN D 2 Routine
146. udes into gun bushing hole Olo i e o as seen from the front of machine 2912 lt FIGURE 218 ala a ojo TRIGGER RECEPTACLE 2912 5 GUN RECEIVER BUSHING 2 2 INTERCHANGABLE 218 L WIRE DRIVE UNIT 4 2 HANDLE GUNTUBE S e GUN NOZZLE em cc GUN AND CABLE E M Y J GUN TRIGGER J 7 CONNECTOR 7 oe CONNECTOR END K466 10 Return to Section TOC Return to Master TOC LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC Return to Master TOC Ojo O Fg 515 5 5 2 2 2 Return to Section TOC Return to Master TOC A 11 PROCEDURE FOR CHANGING DRIVE AND IDLE ROLL SETS See Figure A 4 A WARNING ELECTRIC SHOCK can kill Turn the input power OFF at the welding power source before instal lation or changing drive rolls and or guides Do not touch electrically live parts When inching with the gun trigger electrode and drive mechanism are hot to work and ground and could remain energized several seconds after the gun trigger is released Only qualified personnel should perform mainte nance work 1 Turn power off at the welding power source 2 Release the idle roll pressure arm 3 Remove the outer wire guide by turning the knurled thumbscrew
147. urn to Section TOC 14 PIN AMPHENOL CONNECTOR TO POWER SOURCE CONTROL E e 5 6 915 2 8 5 5 45 ojo 551 563 587 608 558 601 589 se Ista sts ste COMMON ANALOG P C BOARD K E AR Tf 3 7 8 9 101112 13 14 15 16 12345 MM 12 5 Hd UM NOTES CAMTY NUMBERING SEQUENCE AS VIEWED FROMCOMPONENT SIDE OF BOARD N B CAVITY NUMBERING SEQUENCE AS VIEWED FROM LEAD SIDE OF CONNECTOR TOGGLESWTCFES ANDPOTENTIOMETERS SHOWN FROMCONNECTIONSIDE OF SWITCH PIN NEAREST THE FLAT EDGE OF LEDLENS ALIG S WITH WHITE LEAD OF LEDSOCKET Return to Section TOC Return to Master TOC NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual The wiring diagram specific to your code is pasted inside one of the enclosure panels of your machine LINCOLN LF 72 74 ni ELECTRICAL DIAGRAMS GA WIRING DIAGRAM ENTIRE MACHINE CODE 11290 11291 11292 11293 L12146 2 LF 72 CAVITY NUMBERING SEQUENCE GENERAL INFORMATION COMPONENT SIDE OF P C BOARD ELECTRICAL SYMBOLS PER E1537 WRE FEED SPEED 17 lox COLOR CODE CONTROL BLACK POTENTIOVETER WHITE RED BLUE Return to Section TOC Return to Master TOC INPUT ELECTRODE er CABLE CONNECTION FEED PLATE TACH R
148. wer to the power source at the disconnect switch or fuse box before working on this equipment Turn off the input power to any other equipment connected to the welding system at the disconnect switch or fuse box before working on this equipment Return to Section TOC Return to Master TOC Do not touch electrically hot parts WELD CABLE SIZES Table A 1 has the copper cable sizes recommended for different currents and duty cycles Lengths stipulated are the distance from the welder to work and back to the welder again Cable sizes are increased for greater lengths primarily for the purpose of minimizing voltage in the welding circuit Return to Section TOC Return to Master TOC TABLE AA 1 RECOMMENDED CABLE SIZES RUBBER COVERED COPPER RATED 75 C CABLE SIZES FOR COMBINED LENGTHS OF ELECTRODE AND WORK CABLES Percent 0 to 50 Ft 50 to 100Ft 100 to 150 Ft 150 to 200 Ft 200 to 250 Ft Duty Amperes 0 to 15 m 15 to 31 31 to 48 48 to 61 m 61 to 76 m ojo 515 0 915 2 2 SZ Tabled values are for operation at ambient temperatures of 40 C and below Applications above 40 C may require cables larger than recommended or cables rated higher than 75 C Return to Section TOC Return to Master TOC LF 72 74 LINCOLN 5 Return to Section TOC Return to Master TOC Return to Section TOC ojo O 515 0 9 0 2 2 SZ
149. x our e POSQTIVE OPERATION MN 1009 025 REQ or e veer 4 aot Som 2 R28 4 E ME L A Dor 820 20 2 Be ig 8 ud 5 8 H TIN SEIS COMMON 1 EL 1 414 4 4 e 5 6 515 l 2 8 5 5 45 ojo GENERAL INFORMATION oy ELECTRICAL SYMBOLS PER E1537 us LABELS 2 SUPPLY VOLTAGE NET DIDUES 1A400V UNLESS OTHERWISE SPECIFIED POWER SUPPLY SOURCE POINT 57 COMMON CONNECTION 7 7 FRAME CONNECTION DOCUM PROPRIET OBAL INC AND MAY NOT BE DUPLICATED COMMUNICATED PROPRIETARY amp CONFIDENTIAL 105 PARTES UR USED FOR ANY PURSE THE EXPRESS WRITTEN PERMISSION UF LINCOLN GLOBAL INC EQUIPMENT TYPE COMMON WIREDRIVE CONTROL BRAWN BY 5 SUBJECT SCHEMATIC CONTROL PCB wen REVISION RN ess emos ss Dawna uote 4724 2006 4559 260 EZ Return to Section TOC Return to Master TOC NOTE This diagram is for reference only It may not be accurate for all machines covered by this manual LINCOLN LF 72 74 ELECTRICAL DIAGRAMS SCHEMATIC COMMON ANALOG CONTROL PC BOARD 64559 SHEET 3 es ji Uu g ac Return to Master TOC

Lincoln Electric LF-72/74 Welder User Manual

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