Lincoln Electric SP-100 service manual 3THEORY of Operation, TRIGGER, GAS Solenoid and Wire Drive

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E-3THEORY OF OPERATION

FIGURE E.3 – Trigger, Gas Solenoid and Wire Drive

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TRIGGER, GAS SOLENOID AND WIRE DRIVE

Closure of the trigger circuit (pulling the gun trigger) signals the control board to start several functions. 115 vac is applied to the gas solenoid to allow shielding gas to flow. The SCRs are activated and voltage is applied to the main transformer. Output volt- age is developed at the output terminals and fed back to the control board. This welding output voltage is also used to power the wire drive motor.

The welding output voltage that powers the wire drive motor is varied and controlled on the control board. The control board moni- tors the drive motor armature current and voltage and compares the feedback infor- mation with the commands sent from the wire speed control. The control board varies and controls power to the drive motor, which, in turn, controls the speed of the wire drive. The SP-100 also has an automatic protection circuit which protects the wire drive motor from excessive motor over- loads.

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NOTE: Unshaded areas of block logic diagram are the subject of discussion.

SP-100

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Contents SP-100 ARC Rays can burn SafetyElectric Shock can kill Fumes and Gases can be dangerousCylinder may explode if damaged Welding Sparks can cause fire or explosionElectric and Magnetic Fields May be dangerousPrécautions DE Sûreté Sûreté Pour Soudage a L’ArcMaster Table of Contents for ALL Sections Table of Contents Installation SectionInstallation Technical Specifications SP-100Installation Safety PrecautionsRead entire installation section before starting Identify and Locate ComponentsOutput Connections Work Clamp InstallationSelect Suitable Location TiltingConnecting GUN Cable to the SP-100 GUN InstallationGAS Connection Gas Solenoid Inlet Fitting PowerInput Connections InputRequirements for CSA Rated Output Code Requirements for Input ConnectionsRequirements for Maximum Output Requirements for Rated OutputSP-100 Table of Contents Operation Wear eye, ear and body protec- tionGeneral Description Operational Features and ControlsDesign Features Advantages OffProcess Guidelines Wire LoadingWelding Operations Sequence of OperationFriction Brake Adjustments Refer to Figure B-4Shielding GAS Making a WeldOverload Protection SP-100 Accessories Section Lincoln GAS Regulator Kits K467 Input Line Cord 1ACCESSORIESReplacement Parts Innershield Welding KitsMaintenance Section Items Requiring no Maintenance MaintenanceRoutine and Periodic Maintenance Changing Drive Roll Changing the Contact TIPLiner trim length for the Magnum 100L gun red trigger Figure D.3 SP-100 SUB Assemblies SP-100 Theory of Operation Figure E.1 Input Power Circuits Input Line VOLTAGE, FAN Motor and Main TransformerOutput CONTROL, RECTIFICA- Tion and Voltage Feedback Figure E.2 Output CircuitsTRIGGER, GAS Solenoid and Wire Drive 3THEORY of OperationSCR Operation Figure E.4 SCR OperationThermostat protects the machine from Troubleshooting Section Oscilloscope Waveforms1TROUBLESHOOTING & Repair HOW to USE Troubleshooting GuideTroubleshooting & Repair PC Board Troubleshooting ProceduresAuthorized Field Service Troubleshooting GuideFacility Below Code 9794 only Recommended Course of Action Problems SymptomsPossible Areas of Misadjustments Code 9794 and AboveFeeding Problems Troubleshooting Guide PC Board Connector Locations Codes 9794 and above 6J1 10J2 1J1 1J2 Codes below SP-100Volts Volts/Div 9TROUBLESHOOTING & RepairScope Settings Normal Open Circuit Voltage WaveformVolts Typical Output Voltage Waveform Machine LoadedAbnormal Open Circuit Voltage Waveform FAN Blade and Motor Removal Procedure DescriptionProcedure Tools Required1A. for Codes Above Wire Drive Assembly RemovalMotor Removal Procedure 1B. for Codes belowMain Transformer Secondary Voltages Test Points Wire Speed RangeRetest After Repair Input Amps AT Rated Output Input Amps AC @ Output DCSP-100 Electrical Diagrams Section Wiring Wiring DiagramsDiagram SP-100 Wiring Diagram Codes Below 4 5 1 MElectrical Diagrams Electrical Diagrams Control P.C. Board G1842Control P.C. Board G2314 Control P.C. Board G2314 SCR1, SCR2 SCR 81 Heatsink AsblyMachine Schematic Codes 9794 and Above ErrorMachine Schematic Codes Below 86R R63R64 1 5 KSVM Error Reporting Form