Lincoln Electric R3R-300, R3R-500 service manual Typical Output Voltage Waveform Machine Loaded

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F-36

F-36

TROUBLESHOOTING & REPAIR

TYPICAL OUTPUT VOLTAGE WAVEFORM – MACHINE LOADED

0 volts

20 volts

5 ms

This is the typical DC voltage wave- form generated from a properly oper- ating machine. Note that each verti- cal division represents 20 volts and that each horizontal division repre- sents 5 milliseconds in time. The machine was loaded with a resis- tance grid bank. The meter reads 500 amps at 40VDC.

Note: Scope probes connected at

machine output terminals: (+) probe to positive terminal, (-) probe to neg- ative terminal. (R3R 500 machine)

SCOPE SETTINGS

Volts/Div	20V/Div.
Horizontal Sweep	5 ms/Div.
Coupling	DC
Trigger	Internal

IDEALARC R3R

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Contents Idealarc R3R-300, -400 Safety California Proposition 65 WarningsElectric Shock can kill Cylinder may explode if damaged Précautions DE Sûreté Master Table of Contents for ALL Sections Table of Contents Installation Section Installation Technical Specifications Idealarc R3R-300Technical Specifications Idealarc R3R-400 Technical Specifications Idealarc R3R-500 Lifting Safety PrecautionsSelect Suitable Location TiltingGround Connection Input ConnectionsInput Supply Connections Input Wire and Fuse Size Figure A.2 Input Power Supply ConnectionsReconnect Procedure Input Supply Connection DiagramOutput Connections STICK, TIG, AIR/CARBON ARC Cutting Return to SectionIdealarc R3R Table of Contents Operation Section OPERATIONB-2 Safety InstructionsOperating Instructions General Description Design Features and AdvantagesOperation Recommended ProcessesControls and Settings Figure B.1 Case Front ControlsOperation Welding Operation Operating StepsTable of Contents Accessories Section Factory Installed Options AccessoriesOPTIONS/ACCESSORIES Field Installed OptionsTable of Contents Maintenance Section Maintenance Routine and Periodic MaintenanceFigure D.1 General Component Locations Idealarc R3R Table of Contents Theory of Operation Section Theory of Operation Input Line Voltage Contactor and Main TransformerOutput Rectification CONTROL, and Feedback Figure E.3 Output RECTIFICATION, CONTROL, and FeedbackOptional Polarity Switch and Pocket Amptrol Circuits Protective Devices and Circuits SCR Operation Figure E.5 SCR OperationTable of Contents Troubleshooting & Repair Section Troubleshooting & Repair HOW to USE Troubleshooting GuidePC Board Troubleshooting Procedures PC Board can be damaged by static electricityTroubleshooting Guide Output ProblemsSCR/Diode Pocket Amptrol Circuit Input Contactor Output Problems Welding Problems Description Materials NeededTest Procedure Input Contactor TestRemoved Test for Contact Continuity Description Figure F.3 DC Coil Input Contactor Connections Removed Control Transformer T2 Voltage Test Control Transformer T2 Voltage Test Figure F.5 Control Transformer and Lead LocationsTroubleshooting & Repair Main Transformer T1 Voltage Test Main Transformer T1 Voltage Test Figure F.8 Main Secondary Lead Test Points Phase Angle Winding Test Table F.1Figure F.9 Control Board G2206 Test Points Static SCR/DIODE Rectifier Bridge Test Static SCR/DIODE Rectifier Bridge Test Static SCR/DIODE Rectifier Bridge Test Figure F.13 Snubber Board M15370 Plug P5 LocationSCR Test Active SCR Test Active SCR Test Active SCR Test Figure F.20 SCR Tester Circuit and SCR ConnectionsPocket Amptrol Circuit Test Pocket Amptrol Circuit Test Figure F.21 T3 Transformer and Leads Pocket AmptrolFigure F.22 Pocket Amptrol Board Plug P6 and P7 Location Figure F.23 Sensing Resistor R4 Scope Settings Maximum Output Setting no LoadNormal Open Circuit Voltage Waveform Typical Output Voltage Waveform Machine Loaded Typical SCR Gate Voltage Waveform CH1Abnormal Output Voltage Waveform ONE Output SCR not FunctioningInput Contactor CR1 CLEANING/REPLACEMENT Cleaning Procedure Input Contactor CR1 CLEANING/REPLACEMENTContactor Replacement Procedure FAN Motor and Blade Removal and Replacement FAN Motor and Blade Removal and Replacement ProcedureSCR/DIODE Rectifier Assembly Removal and Replacement SCR/DIODE Rectificer Assembly Removal and ReplacementTroubleshooting ReassemblySCR Removal and Replacement SCR Removal and Replacement Special InstructionsProcedure for the 1/2 Inch Wide Spring Figure F.29 1/2 Wide Leaf SpringClamping Procedure For 1/4-28 CAP Screws Clamping Procedure For 1/4-20 CAP ScrewsProcedure for Inch Wide SpringAfter Replacing the SCRs Mounting of Stud Type Diodes to Aluminum Heat Sinks Mounting of Stud Type Diodes to Aluminum Heat SinksMain Transformer Removal and Replacement Main Transformer Removal & Replacement Removal of Lift BailRemoval of Choke and TOP Iron Assembly Figure F.34 Choke RemovalReassembly of Transformer Coils Figure F.35 Epoxy MIX Application AreasFigure F.36 Coil Lead Placement Figure F.38 Secondary Lead Trim and Weld Detail Reassembling the Main Transformer Into the Machine Reassemble the Lift BailOpen Circuit Voltages Retest After Repair R3RInput Idle Amps and Watts Welding Output Load TestWelding Output Terminals 63/69VDC 61/66VDC Welding Output Terminals 64/72VDC 61/69VDC Idealarc R3R Electrical Diagrams Idealarc R3R Electrical Diagrams DIAGRAMSELECTRICALG-4 Idealarc R3R-400, 500-I, 500 & 600-I Wiring Diagram Pocket Amptrol Schematic Snubber Board Schematic & Layout R3R-300 Control PC Board R3R-400 Control PC Board R3R-500 Control PC Board