Lincoln Electric SVM179-B service manual Theory of Operation, Figure E.2 General Description

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E-2

THEORY OF OPERATION

E-2

FIGURE E.2 — GENERAL DESCRIPTION

ELECTRODE

67

INPUT

INPUT

CONTACTOR

CURRENT TRANSDUCER

FEEDPLATE

SOLENOID

POLARITY

V M

TIMER OPTION

MOTOR

TACH

GUN

MOTOR

OVERLOAD

ARMATURE

CONTROL BOARD

21

TACH FEEDBACK

1

GUN TRIGGER

WIRE

REMOTE

14 PIN AMPHENOL

SPEED

VOLTAGE

COLD

CC

TRIGGER

GAS

21

FEED

CV

INTERLOCK

PURGE

DIGITAL

RUN IN

DISPLAY

BOARD

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GENERAL DESCRIPTION

Several models of the LN-25™ PRO are offered to best meet the individual welders needs. The Extra Torque model features additional torque for reliable feeding of large diameter FCAW wire. The standard and control cable models feature wire drive gearing for optimal per- formance with both FCAW and GMAW wires of com- mon sizes. All the models include a gas solenoid and flow meter for the flexibility to run most wire processes. Control Cable models also includes digital meters and remote voltage control.

The plastic case is molded from high impact, flame retardant plastic for durability and low weight. The patent pending design keeps the internal components protected and dry.

The heart of the LN-25™ PRO is a 2 roll MAXTRAC wire drive system. The patented features on the wire drive offer tool-less changing of the drive rolls and wire guides for quick changeovers. A tachometer controlled motor powers the patent pending drive rolls for smooth, steady feeding without slippage.

With only one p.c. board, the LN-25™ PRO is designed to be simple, reliable and easy to service. The p.c. board is manufactured with Lincoln’s industry leading environmental design protection which involces mount- ing the board in a plastic tray and potting it with epoxy.

With a 325 amp, 100% duty cycle rating, these feeders are ready for heavy duty welding.

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NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion

LN-25™ PRO

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Contents LN-25PRO Wire Feeder Safety LN-25 PROElectric Shock can kill ARC Rays can burn For Electrically Welding CuttingIii Précautions DE Sûreté Sûreté Pour Soudage a L’ArcMaster Table of Contents for ALL Sections Table of Contents Installation Section Installation Safety Precautions High Frequency ProtectionLocation ELECTRIC SHOCK can KillWire Drive Configuration Cable ConnectionsShielding GAS Connection Changing the GUN Receiver BushingProcedure to Install Drive Rolls Wire GuidesLoading Spools of Wire Pressure ARM AdjustmentGUN Connection Across the ARC SET-UPS Power Source to LN-25 PRO Cable Connection DiagramsDescription Figure A.7 Table of Contents Operation Section Safety Precautions OperationGeneral Description Description Wire Feed Speed KnobAnalog Voltmeter Wire Feed Speed, CC Operation See Figure B.2 or Figure B.2Table B.2 VV CC Wire Speed Setting Constant Current VS Constant Voltage Wire Welding Figure B-3PIN GUN Trigger Connector See Figure B.1 Wire Feed Speed Range Switch K2613-5 and K2613-7 onlyWork Sense Lead Thermal LED, Motor Overload See Figure B.1Internal Controls Figure B.4Step Trigger Interlock Switch CV/CC SwitchInternal Controls Description Cold Feed PushbuttonOptional PREFLOW, Burnback Postflow Timer KIT K2330-2 Preflow TimerRear Controls Figure B.5POWER-UP Sequence GAS Purge PushbuttonFlow Meter ScfhLN-25 PRO Table of Contents Accessories Section Accessories Factory Installed EquipmentWire Type Drive Roll KitsAccessories Accessories K435 Spindle Adapter, for mounting Installation of the K590-6 Water Cooling KIT Table of Contents Maintenance Section Maintenance Routine MaintenancePeriodic Maintenance Calibration SpecificationCover Wire Feed SpeedBoard Figure D.3. Major Component Location 1TABLE of CONTENTS-THEORY of Operation Section E-1 Control BoardTheory of Operation Figure E.2 General DescriptionInput Power TRIGGER CIRCUITFeedback and Control CIR- Cuits Figure E.4 Feedback & Control CircuitsOptional Circuits Figure E.5 Optional Circuits & Digital Display BoardLN-25 PRO Table of Contents Troubleshooting & Repair Troubleshooting & Repair HOW to USE Troubleshooting GuidePC Board Troubleshooting Procedures Fault Code Description Possible Adjustment Motor Solenoid Test Possible Areas Misadjustments Problems SymptomsRecommended Course of Action LN-25 PRO Test Description Case Removal ProcedureMaterials Needed Procedure Figure F.1 Case RemovalGAS Solenoid Test GAS Solenoid Control BOX Control BOX Cover Contactor Test Control BOX Contactor Drive Motor and Tach Feedback Test Case Control BOX Assembly Motor Overload Test Figure F.5 Control BOX Assembly Contactor Removal and Replacement Procedure Removal Procedure Figure F.6 Control BOXReplacement Procedure Figure F.7 Buss BAR and Mounting BlockLN-25 PRO Front Panel Removal and Replacement Procedure Front Panel Troubleshooting & Repair Gas Hose Control BOX Wire Drive Panel Drive Gear Cover LN-25 PRO PC Board Removal and Replacement Procedure PC BOARD Removal and Replacement Procedure Figure F.11 Control PC Board LocationGAS Solenoid Removal and Replacement Procedure GAS Solenoid GAS Hose Control BOX Lock NUT SET UP Retest After RepairRetest a machine Operation VerificationLN-25 PRO Table of Contents Diagram Section Wiring Diagram LN-25 PRO WiriNG DiaGram lN-25 prO CODEs 11507, 11508 G5681-1 Wiring DIAGRAM- LN-25 PRO Analog WiriNG DiaGram lN-25 prO CODEs 11746, 11747 G5681-3 LN-25 PRO Wire Feeder G5683LN-25 PRO Wire Feeder ElECTriCal DiaGrams G5683-1 Pushbutton G5683-2 LN-25 PRO AnalogG5683 G5683-3 Circuitryconfidential Equipmenttype Xres RXD Work 624 4783-1C0 Flexiblepowerfeede R 50V OF05 Circuitryconfidential S27505-1B0 R2 CW