Lincoln Electric SVM208-A Rheostat Removal and Replacement, Figure F.11 Rheostat Removal

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F-36	TROUBLESHOOTING AND REPAIR	F-36

RHEOSTAT REMOVAL AND REPLACEMENT (continued)

FIGURE F.11 – RHEOSTAT REMOVAL

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PROCEDURE

1.Remove the spark plug wire.

2.With the 3/8” nut driver, remove the 4 sheet metal screws that hold the top cover to the con- trol box. Remove the top cover.

3.With the small slot head screw driver, loosen the screw that holds the knob to the rheostat shaft. The shaft has a flat for locating the knob at reassembly.

4.With a 9/16” open or box end wrench, remove the nut that holds the rheostat to the control panel. Support the rheostat with your hand as you turn the nut. There is a shake-proof wash- er under the nut.

5.Pull the rheostat back out of the control panel and lay it out on its wires to loosen the nuts that hold them.

6.With the 5/16” open or box end wrench, remove the brass nuts from the wire terminals. Support the terminals as you turn the wrench to avoid ripping the terminals from their foundations. Note the wire locations for reassembly.

NOTE: The brass screws are double-nutted with a shake-proof star washer under the screw head.

7.To reinstall the rheostat, replace each of the brass screws. Place a shake-proof star wash- er under the head, insert the screw into the rheostat and tighten down one nut. Replace the appropriate wires and tighten down the second nut. Again, support the terminals as you turn the wrench to avoid ripping the termi- nals from their foundations.

8.Reassemble the rheostat to the front of the control panel. Line up the locating tab on the rheostat with the slot on the control panel hole.

9.Reassemble the shake-proof star washer and nut and tighten securely with the 9/16” wrench.

10.Locate the flat spot on the shaft, line up the knob locking screw, push the knob onto the shaft and tighten the screw with the small slot head screw driver.

11.Check the rheostat knob for proper rotation, minimum to maximum.

12.Replace the top cover of the control box and tighten the 4 sheet metal screws with the 5/16” nut driver.

BULLDOG® 140

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Contents Bulldog Safety California Proposition 65 WarningsElectric Shock can kill ARC Rays can burn Can be dangerousWelding and Cutting Sparks can cause fire or explosion Cylinder may explode if damagedIii Précautions DE Sûreté Sûreté Pour Soudage a L’ArcSafety Methods of Reducing Emissions Mains Supply Master Table of Contents for ALL Sections Table of Contents Installation Section Installation Technical Specifications Bulldog 140 K2708-1Safety Precautions Location and VentilationStoring Engine Exhaust can killPRE-OPERATION Engine Service StackingTilting OILElectrical Output CONNEC- Tions Welding Cable ConnectionsTable A.1 Recommended Welding Cable Size and Length Auxiliary Power Receptacles Cable InstallationElectrical Connections Plugs and HAND-HELD EquipmentPremises Wiring Circuit BreakersAtion. do not RUN These BulldogTable of Contents Operation Section Operation Limitations WELDER/GENERATOR ControlsOutput Panel Controls Engine Operation Gasoline Engine ControlsBefore Starting the Engine Starting the EngineGenerator Operation Table B.1 Generator Power Applications Welding Operation Control Function / OperationMaterial Thickness Electrode Type Size Setting Welding GuidelinesStick Welding Learning To Stick WeldWhat Happens in the Arc? Correct Welding Position Side viewPractice Use the followingDo the following Butt JointsFillet Joints PenetrationVertical-Up Welding Vertical-Down WeldingHow to Hardface the Sharp Edge Metal to Ground Wear Overhead WeldingWelding Sheet Metal Hardfacing To Reduce WearWelding Cast Iron Cast Iron Plate PreparationHigh-Speed Group AWS E6013 Low Hydrogen Group AWS E7018Out-of-Position Group AWS E6011 Bulldog Table of Contents Accessories Section Accessories OPTIONS/ACCESSORIESLincoln Electric Accessories Table of Contents Maintenance Section Maintenance Routine and Periodic Maintenance Engine MaintenanceLocation Engine Adjustments Return to Section TOC To Section TOCTable D.1 Engine Maintenance Parts Spark Plug ServiceOperational Clearance GENERATOR/WELDER Maintenance Screws BrushesFigure D.7. Major Component Locations Bulldog 1TABLE of CONTENTS-THEORY of Operation Section E-1 Theory of Operation ENGINE, EXCITATION, Rotor StatorRotor Field Feedback Auxiliary Power Figure E.3 Rotor Field Feedback and Auxiliary PowerAuxiliary Power Overcurrent Protection Weld Winding and Reactor1TABLE of Contents Troubleshooting and Repair F-1 Troubleshooting and Repair HOW to USE Troubleshooting GuidePC Board Troubleshooting Procedures Output Problems Electric Authorized Field Ser vice Facility Perform the Rotor Voltage TestProblems Symptoms Troubleshooting and Repair Perform Field Diode Test Engine Problems Troubleshooting and Repair Engine Throttle Adjustment Test Bulldog Rotor Voltage Test Test DescriptionMaterials Needed Procedure Rotor Voltage TestLead 200A Connection Ground Stud Field Diode Bridge Test Field Diode Bridge Test + ~Rotor Flashing Circuit Test Rotor Flashing Circuit Test Figure F.3 Brush Holder Leads 201- and 202B +Moving Parts can injure Bulldog Rotor Resistance Test Rotor Resistance Test Cable TIE Brushes Figure F.6 Brushes Retained with Cable TIEBulldog Engine Throttle Adjustment Test ROBIN/SUBARU Engine Engine Throttle Adjustment Test ROBIN/SUBARU EngineStrobe-tach Method Frequency Counter MethodHigh Speed Stop Screw Scope Settings Normal Open Circuit Voltage Waveform 115VAC Supply High Idle no LoadTypical Weld Output Waveform Machine LoadedMachine Loaded to 125 Amps AT 23 VAC Brush Removal and Replacement Brush Removal and Replacement Cable TIE BrushesReturn to Section Return to Section TOC Bulldog Rheostat Removal and Replacement Rheostat Removal and Replacement Figure F.11 Rheostat RemovalCapacitor AND/OR Diode Bridge Removal and Replacement Removal and Replacement Procedure Capacitor Removal and ReplacementCapacitor AND/OR Diode Bridge Procedure Field Diode Bridge Removal and Replacement Figure F.13 Field Diode Bridge LocationBulldog STATOR/ROTOR Removal and Replacement InstructionsSTATOR/ROTOR Removal and Replacement GeneratorengineFigure F.15 Generator Components Troubleshooting and Repair Stator Removal Procedure Figure F.16 Output Lead Location TIE Wrap TerminalsThru Bolts Support NutsRotor Removal Procedure Reassembly ProcedureFigure F.19 Checking ROTOR-STATOR AIR GAP Auxiliary Power Receptacle OUTPUT1 Retest After RepairEngine Output WELDER/GENERATOR OUTPUT1Bulldog Table of Contents Diagram Section Wiring Diagram Bulldog S28101