Theory of Operation | Lincoln Electric SVM208-A instruction

E-2	THEORY OF OPERATION	E-2

FIGURE E.2 - ENGINE, EXCITATION, ROTOR AND STATOR

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ENGINE

MAGNETO

MECHANICAL ROTATION

ROTOR

SLIP

RINGS

CAPACITOR

REACTOR

OUTPUT

TERMINALS

STATOR

ROTOR

STATOR

Return

115 AND 230VAC

RECEPTACLES

RHEOSTATBRIDGE

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ENGINE, EXCITATION, ROTOR

AND STATOR

A small voltage developed by the engine magneto is fed through a diode to the rotating field coil in the rotor via a brush and slip ring configuration. This excitation (“flashing”) voltage magnetizes the rotor lamination. The rotor is mechanically coupled to the engine. The rotating magnet induces a voltage in the stationary windings of the main alternator (stator).

Three separate and isolated windings are incorporated in the stator lamination assembly. Each winding set has a different number of turns, producing different magnitudes of AC output voltages. The three windings are the weld winding, the auxiliary power winding and the field feedback winding. The field feedback winding provides rotor current during machine operation. The output of the BULLDOG 140 is dependent on two cri- teria: the engine RPM and the amount of current in the rotor winding.

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NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion

BULLDOG® 140

Image 46

Lincoln Electric SVM208-A service manual Theory of Operation, ENGINE, EXCITATION, Rotor Stator

Contents

Bulldog Safety California Proposition 65 Warnings Electric Shock can kill ARC Rays can burn Can be dangerous Cylinder may explode if damaged Welding and Cutting Sparks can cause fire or explosionIii Précautions DE Sûreté Sûreté Pour Soudage a L’Arc Safety Methods of Reducing Emissions Mains Supply Master Table of Contents for ALL Sections Table of Contents Installation Section Installation Technical Specifications Bulldog 140 K2708-1 Storing Safety PrecautionsLocation and Ventilation Engine Exhaust can kill Tilting PRE-OPERATION Engine ServiceStacking OIL Welding Cable Connections Electrical Output CONNEC- TionsTable A.1 Recommended Welding Cable Size and Length Electrical Connections Auxiliary Power ReceptaclesCable Installation Plugs and HAND-HELD Equipment Premises Wiring Circuit Breakers Ation. do not RUN These Bulldog Table of Contents Operation Section Operation WELDER/GENERATOR Controls LimitationsOutput Panel Controls Engine Operation Gasoline Engine Controls Before Starting the Engine Starting the Engine Generator Operation Table B.1 Generator Power Applications Welding Operation Control Function / Operation Stick Welding Material Thickness Electrode Type Size SettingWelding Guidelines Learning To Stick Weld What Happens in the Arc? Correct Welding Position Side view Do the following PracticeUse the following Butt Joints Fillet Joints Penetration Vertical-Up Welding Vertical-Down Welding Welding Sheet Metal How to Hardface the Sharp Edge Metal to Ground WearOverhead Welding Hardfacing To Reduce Wear Welding Cast Iron Cast Iron Plate Preparation Low 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 TOC Spark Plug Service Table D.1 Engine Maintenance PartsOperational Clearance GENERATOR/WELDER Maintenance Screws Brushes Figure D.7. Major Component Locations Bulldog 1TABLE of CONTENTS-THEORY of Operation Section E-1 Theory of Operation ENGINE, EXCITATION, Rotor Stator Rotor Field Feedback Auxiliary Power Figure E.3 Rotor Field Feedback and Auxiliary Power Auxiliary Power Overcurrent Protection Weld Winding and Reactor 1TABLE of Contents Troubleshooting and Repair F-1 Troubleshooting and Repair HOW to USE Troubleshooting Guide PC Board Troubleshooting Procedures Output Problems Electric Authorized Field Ser vice Facility Perform the Rotor Voltage Test Problems 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 TIE Bulldog Engine Throttle Adjustment Test ROBIN/SUBARU Engine Strobe-tach Method Engine Throttle Adjustment TestROBIN/SUBARU Engine Frequency Counter Method High Speed Stop Screw Scope Settings Normal Open Circuit Voltage Waveform 115VAC Supply High Idle no Load Machine Loaded Typical Weld Output WaveformMachine Loaded to 125 Amps AT 23 VAC Brush Removal and Replacement Brush Removal and Replacement Cable TIE Brushes Return to Section Return to Section TOC Bulldog Rheostat Removal and Replacement Rheostat Removal and Replacement Figure F.11 Rheostat Removal Capacitor 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 Location Bulldog STATOR/ROTOR Removal and Replacement Instructions STATOR/ROTOR Removal and Replacement Generatorengine Figure F.15 Generator Components Troubleshooting and Repair Stator Removal Procedure Figure F.16 Output Lead Location TIE Wrap Terminals Thru Bolts Support Nuts Rotor Removal Procedure Reassembly Procedure Figure F.19 Checking ROTOR-STATOR AIR GAP Engine Output Auxiliary Power Receptacle OUTPUT1Retest After Repair WELDER/GENERATOR OUTPUT1 Bulldog Table of Contents Diagram Section Wiring Diagram Bulldog S28101