Lincoln Electric SVM146-A service manual Pulse Width Modulation, Minimum Output, Maximum Output

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E-9

E-9

THEORY OF OPERATION

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PULSE WIDTH MODULATION

The term PULSE WIDTH MODULATION describes how much time is devoted to conduction in the posi- tive and negative portions of the cycle. Changing the pulse width is known as MODULATION. Pulse Width Modulation (PWM) is the varying of the pulse width over the allowed range of a cycle to affect the output of the machine.

MINIMUM OUTPUT

By controlling the duration of the gate signal, the IGBT is turned on and off for different durations during a cycle. The top drawing below shows the minimum output signal possible over a 50-microsecond time period.

The positive portion of the signal represents one IGBT group1 conducting for 1 microsecond. The negative portion is the other IGBT group1. The dwell time (off time) is 48 microseconds (both IGBT groups off). Since only 2 microseconds of the 50-microsecond time period is devoted to conducting, the output power is minimized.

MAXIMUM OUTPUT

By holding the gate signals on for 22 microseconds each and allowing only 3 microseconds of dwell time (off time) during the 50-microsecond cycle, the output is maximized. The darkened area under the top curve can be compared to the area under the bottom curve. The more dark area under the curve, the more power is present.

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1An IGBT group consists of two IGBT modules feeding one transformer primary winding.

FIGURE E.8 – TYPICAL IGBT OUTPUTS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

sec

 

 

 

48

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50

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MINIMUM OUTPUT

22sec

3 sec

 

 

 

22 sec

 

 

50sec

MAXIMUM OUTPUT

PRO-CUT 80

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Contents PRO-CUT California Proposition 65 Warnings SafetyElectric Shock can kill Cylinder may explode if damaged Précautions DE Sûreté Master Table of Contents for ALL Sections Table of Contents Installation Section Technical Specifications PRO-CUT InstallationGAS Requirements Technical Specifications Cont’d PRO-CUTStacking Safety PrecautionsSelect Suitable Location Lifting and MovingGround Connection Input Power Cord Connector InstallationInput Wire and Fuse Size Input ConnectionsReconnect Procedure Reconnect ProcedureReturn Return to Section TOC GAS Input ConnectionsTorch Connection Output ConnectionsTable of Contents Operation Section Safety Instructions OPERATIONB-2Operating Instructions General Description Operational Features and ControlsDesign Features Advantages OperationCutting Capability Consumable LifeLimitations Controls and Settings Cutting OperationPilot ARC Considerations Safety Status Indicator User Responsibility Preheat Temperature forProcedure Recommendations Plasma CuttingSuggestions for Extra Utility from the PRO-CUT System Thick Sections of MetalARC Start ARC InitiatedARC Voltage PRO-CUT Accessories Table of ContentsGeneral Options Accessories Table of Contents Maintenance Electric Shock can kill Input Filter Capacitor Discharge ProcedurePeriodic Maintenance Routine MaintenanceMaintenance Table of Contents Theory of Operation Section Theory of Operation Input Line VOLTAGE, Switch and Main TransformerPrecharge and Protection Power BoardFigure E.4 Main Transformer Main TransformerFigure E.5 Plasma Output Board and Torch Output Board and TorchFigure E.6 Control and Display Boards Control and Display BoardsProtection Circuits Overload ProtectionThermal Protection Insulated Gate Bipolar Transistor Igbt Operation Pulse Width Modulation Minimum OutputMaximum Output PRO-CUT Table of Contents Troubleshooting & Repair Section HOW to USE Troubleshooting Guide Troubleshooting & RepairPC Board can be damaged by static electricity PC Board Troubleshooting ProceduresOutput Problems Troubleshooting GuideFunction Problems Air begins to flow when Make sure the air pressure is Cutting Problems LED Function Problems Troubleshooting Guide Materials Needed DescriptionFigure F.1 Location of Input Filter Capacitor Terminals Input Filter Capacitor Discharge ProcedureInput Rectifier Test Input Rectifier Test Test ProcedureTest Point Terminals Analog Meter X10 Range Primary Power Board Resistance Test Capacitor Voltage Test Capacitor Voltage Test Primary Power Board Resistance TestBoard Removal and Replacement Procedure Test Procedure Table F.3 Capacitor Voltages Output Power Board Resistance Test Figure F.4 Output Power Board Lead Locations Output Power Board Resistance TestOutput Power Board Removal and Replacement Procedure Torch Continuity and Solenoid Test Torch Continuity and Solenoid Test Test ProcedureAIR/GAS Solenoid Test Figure F.6 AIR Solenoid AIR/GAS Solenoid TestT2 Auxiliary Transformer Test T2 Auxiliary Transformer Test ProcedureYellow 1J21 Yellow 7J21 115VAC Test Point Expected VoltageTrigger Circuit Test Simplified Trigger Circuit Trigger Circuit TestPerform the Input Filter Capacitor Discharge Procedure PRO-CUT 80 Output Board LED Definitions Figure F.11 Control Board LEDs Control Board LED DefinitionsLOW Voltage Circuit Test T2 Auxiliary Transformer LOW Voltage Circuit TestFigure F.12, Low Voltage Circuit Diagram Test Point Figure F.15 Display Board Test Points Control Board Removal and Replacement Screws Control Board Removal and ReplacementFigure F.18 Control Board Removal from Mounting Pins Display Board Removal and Replacement Figure F.19 Case Front Screw Removal Display Board Removal & ReplacementFigure F.20 Display Board Removal Output Power Board Removal and Replacement Output Power Board Output Power Board Removal & ReplacementFigure F.22 Output Board Lead Locations Replacement Procedure This procedure takes approximately 40 minutes to perform Primary Power Board and Filter Capacitor Removal and ReplacementRemoval Procedure Heatsink Mounting Screws Socket Head Capacitor Removal Capacitor Replacement and P.C. Board ReplacementInput Rectifier Bridge Removal and Replacement Figure F.25 Input Rectifier Lead Locations PRO-CUT Input Rectifier Bridge Removal and ReplacementTroubleshooting & Repair Input Idle Amps and Watts Retest After RepairPRO-CUT Electrical Diagrams Wiring Diagram PRO CUT 2ELECTRICAL Diagrams G-2Cutting Current Setpoint Local Schematic Control PC BoardPRO-CUT 80 Control PC Board Assembly Control Board Code 10574 onlyG3560-1 PC Board Assembly Control Board Code 10577 & 10578 onlySchematic Power PC Board 6ELECTRICAL DIAGRAMSG-6Power PC Board Assembly Power BoardElectrical Reqd Identification PC Board Assembly Output BoardFilename Schematic Display PC BoardLight BAR,LED,GREEN PC Board Assembly Display BoardSVM Error Reporting Form

SVM146-A specifications

Lincoln Electric's SVM146-A is a versatile and powerful multi-process welding machine designed for professionals in various industries. Known for its robustness and reliability, this machine excels in both performance and user-friendly features, making it a popular choice among welders.

One of the standout features of the SVM146-A is its multi-process capability, allowing users to perform MIG, TIG, and stick welding using a single unit. This versatility is enhanced by Lincoln Electric's innovative Auto-Set technology, which automatically adjusts the machine's settings based on the selected process and materials being welded. This feature significantly reduces the time spent on setup and helps ensure optimal weld quality, even for less experienced operators.

The SVM146-A is powered by a reliable inverter design, which provides greater efficiency compared to traditional transformer-based machines. This compact and lightweight design allows for easy transport, making it ideal for job sites or remote locations. The inverter technology also contributes to enhanced arc stability and better overall performance, providing high-quality welds in less time.

Another key characteristic of this welding machine is its robust construction, designed to withstand the rigors of heavy industrial use. The SVM146-A features a durable chassis and control panel, ensuring longevity and reliability under challenging working conditions. Additionally, its intuitive interface allows users to easily navigate settings and make adjustments as needed.

Safety is a paramount concern in welding applications, and the SVM146-A is equipped with several safety features, including over-temperature and over-voltage protection, ensuring that the machine operates safely even in demanding environments. It also features a start inhibit system, preventing the machine from being started under unsafe conditions.

The SVM146-A is compatible with a variety of welding accessories and consumables, enhancing its flexibility and usability across different applications. Whether it’s automotive repair, heavy fabrication, or maintenance work, this welding machine adapts to various tasks, making it a valuable addition to any professional's toolkit.

In conclusion, Lincoln Electric's SVM146-A stands out as a multi-process welding machine that combines advanced technology, robust design, and user-friendly features. It is engineered for performance and reliability, making it an excellent investment for professionals dedicated to achieving high-quality welds.
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