Lincoln Electric SVM134-A service manual Normal Open Circuit DC Weld Voltage Waveform

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F-30

F-30

TROUBLESHOOTING & REPAIR

NORMAL OPEN CIRCUIT DC WELD VOLTAGE WAVEFORM

HIGH IDLE – NO LOAD – FINE CURRENT CONTROL RHEOSTAT AND SELECTOR

SWITCH AT MAXIMUM

0 volts

50 volts

5 ms

This is the typical DC welding output voltage generated from a properly operating machine. Note that each vertical division represents 50 volts and that each horizontal division represents 5 milliseconds in time.

Note: Scope probes connected at machine output terminals.

SCOPE SETTINGS

Volts/Div	50V/Div.
Horizontal Sweep	5 ms/Div.
Coupling	DC
Trigger	Internal

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 ClassicStoring Safety PrecautionsLocation and Ventilation 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 Operating Instructions Safety InstructionsOperation Welder Operational Features and ControlsRecommended Applications GeneratorControls and Settings WELDER/GENERATOR ControlsControl of Welding Current Figure B.2 Current ControlsGasoline Engine Controls Return Section TOCStarting the Engine Engine OperationBefore Starting the Engine BREAK-IN Period Stopping the EngineCold Weather Starting 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 General Description BATTERY, STARTER, Engine Alternator and OIL Switch CircuitTheory of Operation Main SHUNT, Interpole and Series Coils ENGINE, Main Generator Armature and Frame and DC ExciterExcitation Flashing Engine Idler Circuit Fine Current AdjustmentCurrent Range Selector 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 electricityDetailed in the beginning of this manual Troubleshooting GuideObserve Safety Guidelines Shunt Field Winding Test Main Generator Throttle Adjustment Test Output Problems Function Problems Troubleshooting & Repair Engine Problems Welding Problems Materials Needed DC Exciter TestTest Description 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 High Idle no Load Fine Current Control Rheostat AT Maximum Scope SettingsNormal Open Circuit Voltage Waveform 115VDC Supply 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 and Field Coils DC Exciter Armature Removal ProcedureReassembly 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