Lincoln Electric V250-S service manual Input Filter Capacitor Discharge Procedure

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D-2

MAINTENANCE

D-2

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WARNING

ELECTRIC SHOCK can kill.

Have an electrician install and service this equipment.

Turn the input power off at the fuse box before working on equipment.

Do not touch electrically hot parts.

Prior to Performing preventative main- tenance, perform the following capaci- tor discharge procedure to avoid elec- tric shock.

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INPUT FILTER CAPACITOR

DISCHARGE PROCEDURE

1.Turn off input power or disconnect input power lines.

2.Remove the 5/16" hex head screws from the side and top of the machine and remove wrap-around machine cover.

3.Be careful not to make contact with the capacitor terminals that are located in the top and bottom of the Power Board.

4.Obtain a high resistance and high wattage resistor (25-1000 ohms and 25 watts minimum). This resis- tor is not supplied with machine. NEVER USE A SHORTING STRAP FOR THIS PROCEDURE.

5.Locate the four capacitor terminals (large hex head cap screws) shown in Figure D.1. One pair at the top and one pair at the bottom of the Power Board.

6.Use electrically insulated gloves and insulated pli- ers. Hold body of the resistor and connect resistor leads across the two capacitor terminals. Hold resistor in place for 10 seconds. DO NOT TOUCH CAPACITOR TERMINALS WITH YOUR BARE HANDS.

7.Repeat discharge procedure for the capacitor on other two terminals.

8.Check voltage across terminals of all capacitors with a DC voltmeter. Polarity of capacitor terminals is marked on PC board above terminals. Voltage should be zero. If any voltage remains, repeat this capacitor discharge procedure.

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FIGURE D.1 — LOCATION OF INPUT FILTER CAPACITOR TERMINALS.

POWER

UPPER

BOARD

CAPACITOR TERMINALS

 

LOWER

 

CAPACITOR

 

TERMINALS

 

POWER

 

RESISTOR

RIGHT SIDE OF MACHINE

INSULATED

 

PLIERS

INSULATED

GLOVES

INVERTEC V250-S

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Contents Invertec V250-S Safety ARC Rays can burn Electric Shock can killFumes and Gases can be dangerous Cylinder may explode if damaged Welding Sparks can cause fire or explosionPrécautions DE Sûreté Sûreté Pour Soudage a L’ArcMaster Table of Contents for ALL Sections Installation Table of Contents Installation SectionThree Phase Single Phase Technical Specifications Invertec V250-SThree Phase Input Connections Safety PrecautionsSelect Suitable Location Input Fuse and Supply Wire Input Voltage Reconnect ProcedurePower Input Connection for 50/60 HZ Machines Quick Disconnect Plugs Remote Control ReceptacleOutput Connections Output CablesInvertec V250-S Operation Safety Instructions Gouging SparksControls and Settings Figure B.1 Case Front ControlsAIR Carbon ARC Cutting Constant Current ProcessesManual ARC Welding Stick TIG WeldingOverload Protection Parallel OperationThermal Protection Invertec V250-S Accessories Table of Contents Accessories SectionRemote Controls Options / AccessoriesCable Plugs Maintenance Table of Contents Maintenance SectionInput Filter Capacitor Discharge Procedure Figure D.1 Location of Input Filter Capacitor TerminalsRoutine Maintenance Filter Capacitor ConditioningFigure D.2 Location of Maintenance Components Table of Contents Theory of Operation Section Theory of OperationGeneral Description Input Line VoltagePrecharge and Protection Figure E.2 Protection and PRE-CHARGE CircuitsMain Transformer Figure E.3 Main TransformerOutput Rectification Control Figure E.4 Output Rectification and ControlProtection Circuits Overload ProtectionInsulated Gate Bipolar Transistor Igbt Operation Minimum Output Pulse Width ModulationMaximum Output Troubleshooting & Repair HOW to USE Troubleshooting Guide Oscilloscope WarningPC Board Troubleshooting Procedures Board can be dam- aged by static electricityPossible Areas Recommended Symptoms Course of ActionPossible Areas Perform the Control Board Voltage ChecksCapacitor Balance Test Troubleshooting & Repair Perform the Output Diode Test Welding Problems Invertec V250-S Test Description Auxiliary Transformer TestMaterials Needed Test Procedure Auxiliary Transformer TestAuxiliary Transformer Test Table F.1 Auxiliary Transformer Test PointsInvertec V250-S Input Rectifier Test Test Procedure Input Rectifier TestTable F.2 Input Rectifier Test Points Test Point Terminals Analog Meter X10 RangeInvertec V250-S Power Board Resistance Test Power Board Resistance Test Test DescriptionPower Board Resistance Test Table F.3 Power Board Resistance Test PointsInvertec V250-S Output Diodes Test Output Diodes Test Figure F.4 Machine Output TerminalsInvertec V250-S Diode Modules Power Board Voltage Test Power Board Voltage Test Figure F.8 Plug J6 on Power BoardAcceptable Test Description Table F.4. Power Board Voltage Test PointsTest Conditions Invertec V250-S Control Board Voltage Test Control Board Voltage Test Figure F.9 Plugs J1-J5 on Control BoardTable F.5. Control Board Voltage Test Points 18VACInvertec V250-S Protection Circuit Test Protection Circuit Test Figure F.10 Control Board Plug J2 Test PointsProtection Circuit Simplified Invertec V250-S Capacitor Balance Test Figure F.12 Power Board and Capacitor Test Locations Capacitor Balance TestTable F.6 Capacitor Voltages Invertec V250-S Control Board Removal and Replacement Procedure Control Board Removal and ReplacementV250S Control Power Board Removal and Replacement Power Board Removal and Replacement Figure F.14 Power Board Lead LocationsPower Board Replacement Procedure Invertec V250-S Filter Capacitor Removal and Replacement Matched PartsFilter Capacitor Removal and Replacement Figure F.15 Heatsink/Power Board RemovalPerform Power Board Replacement Procedure in this section Invertec V250-S Input Rectifier Bridge Removal and Replacement Input Rectifier Bridge Removal and Replacement Figure F.16 Input Rectifier Lead LocationsTroubleshooting & Repair Invertec V250-S Materials Needed Snubber Resistors Locking Tabs Invertec V250-S Wrench Allen type wrench Torque wrench Mounting Bolts Diode Modules Bolted Connections Troubleshooting & Repair Invertec V250-S Main Transformer Removal and Replacement Machine Codes below T3 Current Transformer Main Transformer Main Transformer Secondary Leads Figure F.22 Main Transformer Mountings Clear all leads and secure for case wrap-around assembly Invertec V250-S Main Transformer Removal and Replacement Machine Codes Above Figure F.23 Main Transformer Right Side Figure F.24 Main Transformer Left Side Figure F.25 Main Transformer Mountings Troubleshooting & Repair Invertec V250-S Retest After Repair Maximum Acceptable Output AT Minimum Output SettingsMinimum Acceptable Output AT Maximum Output Settings Input Idle Amps and Idle WattsInvertec V250-S Electrical Diagrams Invertec V250-S Wiring Diagram Codes 10102 Invertec V250SWiring Diagram Codes 10187 Return to SectionControl PC Board G2666 Layout G2666Power PC Board G2684 Layout Power P.C. BD. AsblyControl PC Board G2666 Schematic Relay CoilsPower PC Board G2684 Schematic From Control BD