Lincoln Electric SVM114-C Theory of Operation, General Description, Control Circuit Operation

Page 34

Return to Section TOC

Return to Section TOC

Section TOC

Return to Master TOC

Return to Master TOC

Master TOC

E-2

THEORY OF OPERATION

E-2

 

GENERAL DESCRIPTION

voltage. It is designed for maximum versatility in

 

 

 

a variety of field applications. It can be used with

 

The LN-25™ is a portable semiautomatic wire

most constant voltage or constant current DC

power sources without the need of a control

feeder designed to operate from a DC arc

cable.

 

FIGURE E.2 – INPUT POWER CIRCUIT.

 

 

 

 

OPTIONAL

 

 

 

 

 

 

CONTACTOR

 

 

 

 

 

 

CONDUCTOR

GUN CABLE

 

 

 

 

BLOCK

 

 

 

COLD

 

 

M

 

GUN

 

 

OPTIONAL

O

HALL

TRIGGER

 

INCH

 

T

CONNECTOR

 

SWITCH

CONTACTOR

O

EFFECT

 

 

 

 

BOARD

R

MODULE

 

ELECTRODE

 

 

 

 

 

 

INPUT CABLE

P

 

 

 

 

 

 

 

 

 

 

 

 

O S

 

 

 

 

 

 

L W

 

 

ARMATURE VOLTAGE

 

 

 

A I

VOLT

 

 

 

TO WORK

R T

 

 

 

 

I C

METER

CONTROL

RPM FEEDBACK

 

 

SENSING LEAD

T H

 

 

 

 

 

 

 

 

Y

 

BOARD

 

 

 

 

WIRE FEED

 

RANGE

 

 

 

 

SWITCH

 

 

 

MODE SWITCH

 

 

 

 

 

 

 

 

 

 

 

 

WIRE SPEED

 

 

 

 

 

 

CONTROL

 

 

 

 

 

SOLENOID

GAS

 

 

 

 

 

PC BOARD

SOLENOID

 

 

 

 

 

EARLY MODELS ONLY - LATER MODELS HAVE CIRCUITRY

 

 

 

 

 

INCLUDED ON CONTROL BOARD

 

Return to

to Section TOC

Return to

to Master TOC

CONTROL CIRCUIT

OPERATION

INPUT POWER CIRCUIT

The DC arc voltage from the power source is applied to the LN-25™ through the electrode cable and work sensing lead. This DC voltage is connected to the polarity switch, which allows the wire feeder to be used in either electrode positive or electrode negative polarity. The voltage is then coupled to the voltmeter and control board. A wire feed mode switch is included to give the user the capability of using a constant voltage or, in some processes, a constant current power source. See Figure E.2.

WELDING CURRENT CIRCUIT

The electrode voltage is also applied to the conductor block through a heavy current carrying cable. The welding gun cable is connected to the conductor block. This combination of welding cable, optional contactor, conductor block and gun cable constitute the welding current path to the electrode wire. See Figure E.2.

Return

Return

NOTE: Unshaded areas of block logic diagrams are the subject of discussion.

LN-25™

Image 34
Contents Semiautomatic Wire Feeder Safety California Proposition 65 WarningsFumes and Gases Electric Shock can killCan be dangerous Cylinder may explode if damaged Welding and Cutting Sparks can Cause fire or explosionIii Précautions DE Sûreté Sûreté Pour Soudage a L’ArcMaster Table of Contents for ALL Sections Table of Contents Installation SectionWire Feed Speed InstallationTechnical Specifications LN-25 CurrentrentSafety Precautions Power Source ConnectionWith CV Adapter INVERTEC, CV300 and Other Newer Lincoln Power SourcesGUN Cable Connection to Feeder For GMA GUN and CablesElectrode Cable Connection Wire Feed Drive Roll and Guide Tube KitsWeld Cable Connection Work Cable ConnectionLN-25 Operation Section Welding Capability OperationRead and Understand Entire Section Before Operating Machine Wire Speed Dial and Range Switch Electrode Polarity SwitchWire Feed Mode Switch LN-25 Instruments ControlsAWG GAS Post PRE-FLOW Timers OptionalWork Clip Lead Remote ARC Voltage Control OptionalMounting 22 to 30 LB READI-REELCOILS Sequence of OperationLoading Electrode Mounting 10 to 30 LB SpoolsGrooves READI-REEL Inside Cage Wires Loading Wire DriveIdle Roll Pressure Setting 6OPERATIONB-6Setting ARC Sensing Wire Feed Speed CC Mode Presetting Wire Feed SpeedSetting Constant Wire Feed Speed CV Mode Minimum Arc VoltsFigure B.4 VV CC Wire Speed Setting Making a WeldWelding Procedure AT END of CoilCylinder may explode if damaged Overvoltage Shutdown Circuit Protection and Automatic ShutdownMotor Overload Shutdown Accessories Section Accessories Section CHow to use Table C.1 AccessoriesLN-25 Option Chart Table C.1K434-1 GAS Flow Timer KIT Optional AccessoriesGAS Solenoid KIT K430-2 for Codes Remote Output Control Options and Control Cable Assemblies K433 Power Source Remote BOXK432 Remote Control Cable Assembly LN-25 Contactor KIT K443-1 for CodesK624-1 42V Remote Output Control Module K439 Remote Extension Cable AssemblyK625, K626, K627 Remote Control Cable Assembly K444, K444-1 or K444-2 Remote Voltage Control KITStyle a Connector Must be Insulated in this AreaTo GUN Switch Connect Leads to Pins a and C DIA. HoleMaintenance Section Routine Maintenance MaintenanceAdjusting Speed Sensor Module Calibration of LN-25 Wire Speed Dial LN-25 Figure E.1 Theory of Operation Block Diagram Theory of Operation SectionGeneral Description Input Power CircuitTheory of Operation Control Circuit OperationFeedback and Control Circuits Trigger CircuitGAS Solenoid Optional CircuitsContactor Later ModelsProtective Devices Circuits Control PC Board FusesLN-25 Troubleshooting and Repair Section 2TROUBLESHOOTING and REPAIRF-2 HOW to USE Troubleshooting GuideTroubleshooting and Repair PC Board Troubleshooting ProceduresFeeding Problems Feeding Problems Hall Effect Materials Needed GAS Solenoid Valve and Solenoid PC Board TestTest Description For Codes below 10500 onlyCase Door Test ProcedureScrew Wire Reel Retaining Collar GAS Solenoid ValveFigure F.2 Solenoid Leads Troubleshooting and Repair 624A 621 J11 GAS Solenoid Valve and Solenoid PC Board Test512 PC Board for K430 GAS Solenoid KITLN-25 GAS Solenoid Valve and Control PC Board Test For Codes Above 10500 onlyFor Codes Above 10500 only Figure F.5 Control BOX Cover RemovalSolenoid Leads Figure F.6. Solenoid LeadsFigure F.7. Applied Voltage Polarity Control PC Board Solenoid Circuitry TestG3425 667 555 691 621 500 512 690LN-25 Hall Effect Module Test G2196 539 541 500 Hall Effect Module Test539 G1757 Figure F.11 Control PC Board Codes Above LN-25 Wire Drive Motor Test Drive Motor Lead IN-LINE Connector Hall Effect Module Contactor & Contactor PC Board Test Contactor Test Procedure Contactor & Contactor PC Board TestS20963 Contactor Coil LeadsContactor PC Board Test 28TROUBLESHOOTING and Repair F-28667 J14 LN-25 Contactor PC Board Replacement Tools RequiredContactor PC Board Replacement Repair Procedure33TROUBLESHOOTING and Repair F-33 Figure F.17 Control PC Board Replacement Control PC Board Replacement Figure F.21. Control PC Board Codes 9812 and belowFigure F.22. Plug Locations for L12253- Control Board J14Figure F.24. Control Board Replacement PC Board Screw Contactor Replacement For Codes below40TROUBLESHOOTING and Repair F-40 Contactor ReplacementFor Codes Above Figure F.26 Phillips Head Screwdriver Wrench Pliers GAS Solenoid Valve AND/OR Solenoid PC Board if Present ReplacementPurge Switch Leads Solenoid Plug J11 GAS SolenoidFigure F.29. Solenoid Assembly Wiring Codes 9812 and below Figure F.31. GAS Solenoid Assembly for Earlier Codes Phillips Head Screwdriver Wrench Slot Head Screwdriver Hall Effect Module 48TROUBLESHOOTING and Repair F-48Drive Motor and Gearbox Replacement and Access to Mylar Insulation Electrode CableG1757 Figure F.34. Drive Motor Replacement Retest After Repair LN-25 Electrical Diagrams Table of Contents Electrical Diagrams SectionWiring Diagram Above Code 11140 G4679 Optional 42 Volt Remote Output ControlWiring Diagram Code 10556 Thru 10500 L10925 Wiring Diagram Code 10100 Thru 10500 L9644 Wiring Diagram below Code 9900 L7545 Schematic Complete Machine Codes Above 11140 G5366 LN-25 Across the ARC ModelSchematic Complete Machine below Code 9900 only G1833 Schematic Control PC BD Above Code 11140 G4616-5 Schematic Control PC BD Code 10556 Thru 10558 G3424-3 Schematic Control PC BD Code 10100 Thru 10500 G2194 L12253 PC Board Assembly Control Abovr Code 11140 L12253-3L12253-3 PC Board Assembly Control Code 10556 Thru 10558 G3425-3 G3425PC Board Assembly Control Code 10100 Thru 10500 G2196-1 PC Board Assembly Control below Code 9900 G1757-6 LN-25 ControlSchematic Contactor PC BD Above Code 10500 M10965 ContactorSchematic Contactor PC BD Code 10100 Thru 10500 M17621 Electrical Diagrams Electrical Diagrams PC Board Assembly Contactor Above Code 10500 L10863-1 L10863PC Board Assembly Contactor Code 10100 Thru 10500 L9670-1 PC Board Assembly Contactor below Code 9900 L9185-2