Lincoln Electric SVM134-A Current Range Selector, Fine Current Adjustment, Engine Idler Circuit

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THEORY OF OPERATION

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ENGINE, MAIN GENERATOR ARMATURE AND FRAME AND DC EXCITER (CONTINUED)

CURRENT RANGE SELECTOR

The selector switch acts as a course current adjust- ment by allowing varying amounts of series windings to be included in the welding current path. The series coils and selector switch are connected in series with the negative output terminal.

FINE CURRENT ADJUSTMENT

The field rheostat control functions as a fine output cur- rent adjustment by controlling the current through the shunt windings, thus controlling the amount of magnet- ism created in the shunt field windings. Open circuit weld voltage can also be controlled by the field rheo- stat control.

ENGINE IDLER CIRCUIT

The idler solenoid is mechanically connected to the engine governor linkage. When welding current is being drawn, the reed switch CR2 is closed. This signals the idler PC board to release (deactivate) the idler solenoid, which then lets the machine go to a high speed condition. Also, when auxiliary power (115VDC) is being used, the current is passed through a reed switch coil located on the idler PC board, which signals the PC board to release the idler solenoid.

When welding ceases or the auxiliary load is removed, a preset time delay of about 15 seconds starts. After approximately 15 seconds, the idler PC board acti- vates the idler solenoid, and the machine will return to a low idle speed condition.

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CLASSIC I

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Contents Classic I TM Safety California Proposition 65 WarningsElectric Shock can kill Welding Sparks can cause fire or explosion IiiPrécautions DE Sûreté Sûreté Pour Soudage a L’ArcMaster Table of Contents for ALL Sections Table of Contents Installation Section Installation Technical Specifications ClassicSafety Precautions Location and VentilationStoring PRE-OPERATION Engine Service Exhaust Spark Arrester Cooling SystemMuffler TrailersMachine Grounding Figure A.1 Ground Stud LocationWelding Cable Connections Auxiliary Power Receptacle PLUGS, and HAND-HELD EquipmentElectrical Output Connections Cable size for combined lengthClassic Table of Contents Operation Section Safety Instructions OperationOperating Instructions Welder Operational Features and ControlsRecommended Applications GeneratorControls and Settings WELDER/GENERATOR ControlsControl of Welding Current Figure B.2 Current ControlsGasoline Engine Controls Return Section TOCEngine Operation Before Starting the EngineStarting the Engine Stopping the Engine Cold Weather StartingBREAK-IN Period Welding Operation After you finish weldingAuxiliary Power Table B.1 Range Settings for Wire SIZE/SPEEDTable of Contents Accessories OPTIONS/ACCESSORIES Semiautomatic Welding AccessoriesConnection of the LN-25 to Connection of Lincoln Electric Wire FeedersWire Feed Module see Figure C.1 Classic I Across the ARC withClassic Table of Contents Maintenance Safety Precautions Routine and Periodic Maintenance Engine MaintenanceFigure D.1 OIL Drain and Refill MAX MIN Figure D.2A Engine Coolant Drain Plug Set the terminal gap with a feeler gauge or gapping After cleaning or when installing a new spark plugGap Specifications 0.032 inch .8 mm Tool. See Figure D.4Battery Maintenance Classic I charging system is NegativeWELDER/GENERATOR Maintenance Return to Section Return to Section TOCIdler Maintenance Figure D.5 Major Component Locations Classic Table of Contents Theory of Operation Section BATTERY, STARTER, Engine Alternator and OIL Switch Circuit Theory of OperationGeneral Description ENGINE, Main Generator Armature and Frame and DC Exciter Excitation FlashingMain SHUNT, Interpole and Series Coils Fine Current Adjustment Current Range SelectorEngine Idler Circuit DC Generator Machines Return to Section TOC Table of Contents Troubleshooting & Repair Section Troubleshooting & Repair HOW to USE Troubleshooting GuidePC Board Troubleshooting Procedures PC Board can be damaged by static electricityTroubleshooting Guide Observe Safety GuidelinesDetailed in the beginning of this manual Shunt Field Winding Test Main Generator Throttle Adjustment Test Output Problems Function Problems Troubleshooting & Repair Engine Problems Welding Problems DC Exciter Test Test DescriptionMaterials Needed Test Procedure DC Exciter TestFigure F.2 Exciter Cover Removal Small Flex Lead Solid Shunt Coil and Series Coil Resistance TestsIdler Solenoid Test Troubleshooting & Repair Main Generator Shunt Field Winding Test Main Generator Shunt Field Winding Test Figure F.6 Plug P10 PIN Assignments TAB Engine Throttle Adjustment Test Engine Throttle Adjustment Test Strobe Tach MethodEngine Throttle Adjustment Test Adjust High IdleAdjust Low Idle Flashing the Fields DescriptionProcedure Flashing the FieldsFigure F.11 Brush HOLDER/BATTERY Jumper Connections Scope Settings Normal Open Circuit Voltage Waveform 115VDC SupplyHigh Idle no Load Fine Current Control Rheostat AT Maximum Normal Open Circuit DC Weld Voltage Waveform Machine Loaded Selector Switch AT Maximum Typical DC Weld Voltage WaveformDC Exciter Armature and Field Coils Removal and Replacement DC Exciter Armature Removal Procedure ReassemblyDC Exciter Armature and Field Coils Field Coils Removal Procedure Perform the DC Exciter Armature Removal ProcedureMain Generator Frame Removal and Replacement Replacement Main Generator Frame Removal Bolt / NUTPerform the DC Exciter Armature Removal Figure F.16 Selector Switch Lead Removal Terminal LeadFigure F.18 Choke Control Cable Removal Loosen Here Main Generator Frame Removal Figure F.20 Front Panel Fastener Removal Troubleshooting & Repair Feet Remove Mounting NUTS, Washers BoltsPerform the DC Exciter Armature Reassembly Procedure Main Generator Armature Removal and Replacement Main Generator Armature Removal Armature is now free to be removed from the engineEngine Output DC Auxiliary Power Receptacle OutputRetest After Repair Welder DC OutputElectrical Diagrams Section Electrical Diagrams Wiring Diagram ClassicWire Feed Module Wiring Diagram Wiring Diagram Wire Feed ModuleSchematic Idler PC Board 16990 MPC Board Assembly Idler PC Board Idler