Lincoln Electric SVM208-A service manual Rotor Resistance Test, Procedure

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F-22

TROUBLESHOOTING AND REPAIR

F-22

 

ROTOR RESISTANCE TEST (continued)

FIGURE F.5 – LOCATION OF ROTOR SLIP RINGS - BRUSH HOLDER ASSEMBLY REMOVED

SLIP

RINGS

PROCEDURE

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1.Conduct the test with the gasoline engine OFF.

2.Remove the spark plug wire to prevent acci- dental engine kickback or starting.

3.Isolate the rotor electrically by removing the generator brushes. Refer to Figure F.5 as you perform the remaining steps.

4.Open the brush holder assembly cover. Squeeze the 2 tabs and depress the cover at the top with a screw driver or your fingernail. The cover will drop open on its bottom hinge.

5.With the 1/4” nut driver, remove the 2 screws that hold the brush holder assembly in place.

6.Slide the brush holder assembly out and lay it aside, held by the 2 wires attached.

7.Measure the resistance across the rotor slip rings.

A.Set the ohmmeter on the low scale (X1).

B.Place one meter probe on one of the rotor slip rings. Place the other probe on the other slip ring.

C.Check the resistance across the slip rings. It should read 7 - 9 ohms.

8.Measure the resistance to ground.

A.Set the ohmmeter on the high scale (X100,000).

B.Place one probe on either of the slip rings. Place the other probe on any good, unpainted ground. Use the ground stud or the rotor thru-bolt.

C.Check the resistance. It should read very high, at least .5 megohm (500,000 ohms).

If the resistance checks meet the specifications, then the rotor is okay.

BULLDOG® 140

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Contents Bulldog Safety California Proposition 65 WarningsElectric Shock can kill ARC Rays can burn Can be dangerousCylinder may explode if damaged Welding and Cutting Sparks can cause fire or explosionIii 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 K2708-1Storing Safety PrecautionsLocation and Ventilation Engine Exhaust can killTilting PRE-OPERATION Engine ServiceStacking OILWelding Cable Connections Electrical Output CONNEC- TionsTable A.1 Recommended Welding Cable Size and Length Electrical Connections Auxiliary Power ReceptaclesCable Installation Plugs and HAND-HELD EquipmentPremises Wiring Circuit BreakersAtion. do not RUN These BulldogTable of Contents Operation Section Operation WELDER/GENERATOR Controls LimitationsOutput Panel Controls Engine Operation Gasoline Engine ControlsBefore Starting the Engine Starting the EngineGenerator Operation Table B.1 Generator Power Applications Welding Operation Control Function / OperationStick Welding Material Thickness Electrode Type Size SettingWelding Guidelines Learning To Stick WeldWhat Happens in the Arc? Correct Welding Position Side viewDo the following PracticeUse the following Butt JointsFillet Joints PenetrationVertical-Up Welding Vertical-Down WeldingWelding Sheet Metal How to Hardface the Sharp Edge Metal to Ground WearOverhead Welding Hardfacing To Reduce WearWelding Cast Iron Cast Iron Plate PreparationLow Hydrogen Group AWS E7018 High-Speed Group AWS E6013Out-of-Position Group AWS E6011 Bulldog Table of Contents Accessories Section OPTIONS/ACCESSORIES AccessoriesLincoln Electric Accessories Table of Contents Maintenance Section Maintenance Engine Maintenance Routine and Periodic MaintenanceLocation Engine Adjustments Return to Section TOC To Section TOCSpark Plug Service Table D.1 Engine Maintenance PartsOperational 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 Test Description Rotor Voltage TestMaterials Needed Rotor Voltage Test ProcedureLead 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 Strobe-tach Method Engine Throttle Adjustment TestROBIN/SUBARU Engine Frequency Counter MethodHigh Speed Stop Screw Scope Settings Normal Open Circuit Voltage Waveform 115VAC Supply High Idle no LoadMachine Loaded Typical Weld Output WaveformMachine 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 Procedure Capacitor Removal and Replacement 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 Engine Output Auxiliary Power Receptacle OUTPUT1Retest After Repair WELDER/GENERATOR OUTPUT1Bulldog Table of Contents Diagram Section Wiring Diagram Bulldog S28101