Lincoln Electric DC-655 service manual Main Transformer T1 Voltage Test, Test Description

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F-22

F-22

TROUBLESHOOTING & REPAIR

MAIN TRANSFORMER (T1) VOLTAGE TEST

WARNING

Service and repair should be performed by only Lincoln Electric factory trained personnel. Unauthorized repairs performed on this equipment may result in danger to the technician or machine operator and will invalidate your factory warranty. For your safety and to avoid elec- trical shock, please observe all safety notes and precautions detailed throughout this manu- al.

If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, contact the Lincoln Electric Service Department for electrical trou- bleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353 (WELD).

TEST DESCRIPTION

This test will determine if the correct voltages are being applied to the primary windings of the main transformer. The secondary windings, the auxiliary windings and the phase angle windings will also be checked.

MATERIALS NEEDED

Volt/ohmmeter (Multimeter)

DC-655 Wiring Diagram

IDEALARC DC-655

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Contents Idealarc DC-655 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 DC-655Input Power Three Phase Select Suitable Location Safety PrecautionsElectrical Input Connections Input Power Supply Connections Input Supply Connection DiagramOutput Connections Electrode and Work CablesAuxiliary Power Control Connections Auxiliary Power TableTerminal Strip 1 T.S.1 Terminal Strip 2 T.S.2Table of Contents Operation Section OPERATIONB-2 Operating InstructionsDesign Features Advantages OperationGeneral Description Recommended Processes and EquipmentDC-655 Figure B.2 Lower Case Front Controls & Connections Machine Protection Auxiliary PowerCase Back Connections Thermal Shutdown Remote Control Leads Fault Protection SHUTDOWN1Over Current Protection Shutdown CV Mode CURRENT-LIMITING CC Mode HOT StartCC Mode ARC Force CC Mode ARC Gouging Welding PerformanceTable of Contents Accessories Field Installed Options Remote Output ControlAutomatic Wire Feeders SEMI-AUTOMATIC Wire FeedersSet the Idealarc DC-655 Power toggle Accessories Semiautomatic Wire Feeders Connecting the LN-7 to the Idealarc DC-655 Terminal Strip GND Negative Positive Figure C.4 Idealarc DC-655 Table of Contents Maintenance General Maintenance Electric Shock can killFigure D.1 General Component Locations Idealarc DC-655 Table of Contents Theory of Operation Section Theory of Operation Down Circuits Protective Devices and Shutdown Circuits SCR Operation Figure E.4 SCR OperationIdealarc DC-655 Table of Contents Troubleshooting & Repair Section Troubleshooting & Repair HOW to USE Troubleshooting GuidePC Board Troubleshooting Procedures Troubleshooting Guide Board LED Chart ControlLED Chart OutputBridge Test Perform the SCR Bridge TestMain See the Idle Shut Down TimerTransformer Test Function Problems Thermal Fan/Snubber PC Troubleshooting & Repair Welding Problems Mode Current Limiting See the Control BoardTest Description Internal Trigger Circuit TestMaterials Needed Trigger Diagram Test ProcedureInternal Trigger Circuit Test Simplified Trigger Diagram. If a resistance SectionFigure F.3 Simplified Trigger Diagram Firing Board Test Firing Board Test Figure F.4 Firing Board Trigger Circuit Test Points and LEDs Main Transformer Test Figure F.5 14-PIN Receptacle Figure F.4 Main Transformer T1 Voltage Test Main Transformer T1 Voltage Test Figure F.6 Input Contactor and Primary LeadsTroubleshooting & Repair Figure F.8 Terminal Strip Figure F.9 Firing Board Plug J5 Pins Control Transformer T2 Test Control Transformer T2 Test Figure F.10 Control TransformerHigh Voltage is present at Control Board Transformer T3 Test Control Board Transformer T3 Test Perform the Control Transformer T2 TestInput Contactor Test Input Contactor Test Transformer T2 TestTest for Contact Continuity Figure F.13 Input Contactor Test ConnectionsStatic SCR Test Static SCR Test Figure F.15 Heat Sink Test Points Active SCR Test Active SCR Test Figure F.17 Heat Sink Test Points Anode Cathode Thermal FAN/SNUBBER Board LED Chart LED Functions and IndicationsControl Board LED Chart LED # LED Functions and IndicationsScope Settings Maximum Output Setting no Load Normal Open Circuit Voltage Waveform Constant Voltage MIGMinimum Output Setting no Load Troubleshooting & Repair Typical SCR Gate Voltage Waveform Constant Voltage MIG Installation Input Contactor CR1 CLEANING/REPLACEMENT DescriptionInput Contactor CR1 CLEANING/REPLACEMENT Cleaning ProcedureSCR Rectifier Bridge Removal Replacement Procedure Procedure Replacement ProcedureSCR Rectifier Bridge Removal Reassembly SCR Rectifier Bridge LEG Assembly Mounting BracketsMain Transformer and Choke Removal Replacement Procedure Main Transformer and Choke Removal Output Choke RemovalMain Transformer Removal Retest After Repair Input Idle Amps and WattsSVM Error Reporting Form Section G Electrical Diagrams Control Board Schematic G3384 Firing Board Schematic G2792 Thermal Fan/Snubber Board Schematic L10123 Control Board Layout G3385-1 Firing Board Layout G2699-2 Thermal Fan/Snubber Board Layout L10124-1 Return to Section TOC