Manuals / Lincoln Electric / Power Tools / Welder

Lincoln Electric SVM136-A Scr Operation, Theory Of Operation, to Section TOC, to Master TOC

Models: SVM136-A

1 102

Download 102 pages 56.21 Kb

Page 39

FIGURE E.5 – SCR OPERATION

to Section TOC

Return to Master TOC

E-5

E-5

THEORY OF OPERATION

FIGURE E.5 – SCR OPERATION

Return

to Section TOC

to Master TOC

INPUT

CATHODE

OUTPUT

ANODE	GATE

GATE

NOTE: AS THE GATE PULSE IS APPLIED LATER IN THE CYCLE THE SCR OUTPUT IS DECREASED.

Return

Return to Section TOC

Return

Return to Master TOC

SCR OPERATION

A silicon controlled rectifier (SCR) is a three-terminal device used to control rather large currents to a load. An SCR acts very much like a switch. When a gate sig- nal is applied to the SCR, it is turned ON, and there is current flow from anode to cathode. In the ON state the SCR acts like a closed switch. When the SCR is turned OFF, there is no current flow from anode to cathode; thus the device acts like an open switch. As the name suggests, the SCR is a rectifier, so it passes current only during positive half cycles of the AC supply. The positive half cycle is the portion of the sine wave in which the anode of the SCR is more positive than the cathode.

When an AC supply voltage is applied to the SCR, the device spends a certain portion of the AC cycle time in the ON state and the remainder of the time in the OFF state. The amount of time spent in the ON state is con- trolled by the gate.

An SCR is fired by a short burst current into the gate. This gate pulse must be more positive than the cathode voltage. Since there is a standard PN junction between gate and cathode, the voltage between these terminals must be slightly greater than 0.6V. Once the SCR has fired, it is not necessary to continue the flow of gate current. As long as current continues to flow from anode to cathode the SCR will remain on. When the anode to cathode current drops below a minimum value called holding current, the SCR will shut off. This normally occurs as the AC supply voltage passes through zero into the negative portion of the sine wave. If the SCR is turned on early in the positive half cycle, the conduction time is longer, resulting in greater SCR output. If the gate firing occurs later in the cycle, the conduction time is less, resulting in lower SCR output.

Return to Section TOC

Return to Master TOC

IDEALARC CV-400

Image 39

Lincoln Electric SVM136-A Scr Operation, Theory Of Operation, Return to Master TOC, Return to Section TOC

Contents

IDEALARC CV-400 SVM136-ASERVICE MANUAL View Safety Info View Safety Info View Safety Info View Safety InfoCALIFORNIA PROPOSITION 65 WARNINGS SAFETYFOR ENGINE powered equipment ELECTRIC AND MAGNETIC FIELDS may be dangerousSAFETY ELECTRIC SHOCK can killARC RAYS can burn FUMES AND GASES can be dangerousSAFETY FOR ELECTRICALLY powered equipmentCYLINDER may explode if damaged WELDING SPARKS can cause fire or explosionReturn to Master TOC PRÉCAUTIONS DE SÛRETÉSAFETY Return to Master TOC Return to Master TOC Return to Master TOCMASTER TABLE OF CONTENTS FOR ALL SECTIONS RETURN TO MAIN INDEXParts Manual Return to Master TOC TABLE OF CONTENTSINSTALLATION SECTION Return to Master TOC Return to Master TOC Return to Master TOCPHASE ONLY INSTALLATIONTECHNICAL SPECIFICATIONS - IDEALARC CV-400 INPUT - THREERead this entire installation section before you start installation SAFETY PRECAUTIONSLOCATION AND VENTILATION INSTALLATIONFIGURE A.1 RATING PLATE LOCATION INSTALLATIONReturn to Section TOC Return to Section TOC Return to Master TOC Return to Master TOCFIGURE A.2 REAR PANEL INSTALLATIONFIGURE A.3 INPUT POWER SUPPLY CONNECTIONS Return to Section TOC Section TOCFIGURE A.4 INPUT CONNECTION DIAGRAM FOR 230/460 VOLTS AC, 50/60 HZ RECONNECT PROCEDUREOUTPUT CONNECTIONS INSTALLATIONReturn to Master TOC Return to Master TOC Return to Master TOC INSTALLATIONReturn to Section TOC Return to Section TOC Return to Section TOC Return to Section TOCReturn to Master TOC Return to Master TOC Return to Master TOC INSTALLATIONReturn to Section TOC Return to Section TOC Return to Section TOC Return to Section TOCSection B TABLE OF CONTENTS - OPERATION SECTIONReturn to Master TOC Return to Master TOC Return to Master TOC Return to Master TOCELECTRIC SHOCK can kill SAFETY INSTRUCTIONSOPERATION OPERATING INSTRUCTIONSReturn to Master TOC Return to Master TOC Return to Master TOC GENERAL DESCRIPTIONOPERATION Return to Section TOC Return to Section TOC Return to Section TOCDuty Cycle OPERATIONReturn to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOCReturn to Master TOC Return to Master TOC CONTROLS AND SETTINGSOPERATION Return to Section TOC Return to Section TOCReturn to Master TOC Return to Master TOC Return to Master TOC WELDING OPERATIONOPERATION Return to Section TOC Return to Section TOC Return to Section TOCReturn to Section TOC Return to Section TOC Return to Section TOC AUXILIARY POWEROVERLOAD PROTECTION OPERATIONReturn to Master TOC Return to Section TOC Return to Section TOC Return to Section TOCReturn to Section TOC Return to Master TOC Return to Master TOC Return to Master TOCReturn to Master TOC ACCESSORIESTABLE OF CONTENTS Return to Master TOC Return to Master TOC Return to Master TOCReturn to Section TOC Return to Section TOC OPTIONS/ACCESSORIESACCESSORIES FIGURE C.1 REMOTE CONTROL ADAPTER CABLE K864FEEDERTERMINAL AUTOMATIC WIRE FEEDERSACCESSORIES FIGURE C.2 NA-3 WIRE FEEDER CONNECTION TO THE IDEALARC CV-400Return to Section TOC Return to Section TOC FEEDERTERMINALACCESSORIES FIGURE C.3 NA-5 WIRE FEEDER CONNECTION TO THE CV-400Return to Section TOC ACCESSORIESReturn to Section TOC Return to Section TOC Return to Section TOC Return to Master TOC Return to Master TOC Return to Master TOCFEEDERTERMINAL SEMIAUTOMATIC WIRE FEEDERSACCESSORIES FIGURE C.4 LN-7 WIRE FEEDER CONNECTION TO THE IDEALARC CV-400Return to Section TOC Return to Section TOC ACCESSORIESFIGURE C.5 LN-8 OR LN-9 WIRE FEEDER CONNECTION TO THE IDEALARC CV-400 Return to Section TOC Return to Section TOCReturn to Master TOC Return to Section TOC Return to Section TOC Return to Section TOCReturn to Section TOC Return to Master TOC Return to Master TOC Return to Master TOCSection D TABLE OF CONTENTS MAINTENANCEReturn to Master TOC Return to Master TOC Return to Master TOC Return to Master TOCSAFETY PRECAUTIONS MAINTENANCEMAINTENANCE ROUTINE AND PERIODICReturn to Section TOC MAINTENANCE11. CASE BACK WITH FAN MOTOR ASSEMBLY Return to Section TOC Return to Section TOC Return to Section TOCReturn to Master TOC Return to Section TOC Return to Section TOC Return to Section TOCReturn to Section TOC Return to Master TOC Return to Master TOC Return to Master TOCto Master THEORY OF OPERATION SECTIONTABLE OF CONTENTS GENERAL DESCRIPTIONMaster TOC THEORY OF OPERATIONINPUT LINE VOLTAGE, CONTACTOR AND MAIN TRANSFORMER Section TOCMaster TOC OUTPUT CONTROL, RECTIFICATION AND FEEDBACKTHEORY OF OPERATION Section TOCFIGURE E.4 - CV-400 TRIGGER AND THERMAL LIGHT CIRCUIT PROTECTIVE DEVICES ANDCIRCUITS THEORY OF OPERATIONReturn to Master TOC SCR OPERATIONTHEORY OF OPERATION to Section TOCReturn to Master TOC Return to Section TOC Return to Section TOC Return to Section TOCReturn to Section TOC Return to Master TOC Return to Master TOC Return to Master TOCTABLE OF CONTENTS TROUBLESHOOTING & REPAIR SECTION Return to Master TOC Return to Master TOC Return to Master TOCReturn to Master TOC Return to Master TOC TROUBLESHOOTING & REPAIRHOW TO USE TROUBLESHOOTING GUIDE Return to Section TOCReturn to TROUBLESHOOTING & REPAIRSection TOC Master TOCReturn to Section TOC Return to Section TOC Return to Section TOC TROUBLESHOOTING & REPAIROUTPUT PROBLEMS Observe Safety GuidelinesReturn to Section TOC Return to Section TOC Return to Section TOC OUTPUT PROBLEMSTROUBLESHOOTING & REPAIR Observe Safety GuidelinesReturn to Section TOC Return to Section TOC Return to Section TOC TROUBLESHOOTING & REPAIROUTPUT PROBLEMS Observe Safety GuidelinesReturn to Section TOC Return to Section TOC Return to Section TOC TROUBLESHOOTING & REPAIROUTPUT PROBLEMS Observe Safety GuidelinesReturn to Section TOC Return to Section TOC Return to Section TOC TROUBLESHOOTING & REPAIROUTPUT PROBLEMS Observe Safety GuidelinesReturn to Section TOC Return to Section TOC Return to Section TOC WELDING PROBLEMSTROUBLESHOOTING & REPAIR Observe Safety GuidelinesReturn to Section TOC CONTROL TRANSFORMER T2 VOLTAGE TESTTROUBLESHOOTING & REPAIR Return to Section TOC Return to Section TOC Return to Section TOCReturn to Master TOC Return to Master TOC CONTROL TRANSFORMER T2 VOLTAGE TEST continuedTROUBLESHOOTING & REPAIR Return to Section TOC Return to Section TOCReturn to Section TOC Return to Section TOC RIGHT SIDE VIEWTROUBLESHOOTING & REPAIR CONTROL TRANSFORMER T2 VOLTAGE TEST continuedReturn to Section TOC INPUT CONTACTOR TESTTROUBLESHOOTING & REPAIR Return to Section TOC Return to Section TOC Return to Section TOC#233 INPUT CONTACTOR TEST continuedX1, #232 TROUBLESHOOTING & REPAIRReturn to Master TOC TROUBLESHOOTING & REPAIRINPUT CONTACTOR TEST continued Return to Section TOCReturn to Section TOC MAIN TRANSFORMER T1 VOLTAGE TESTTROUBLESHOOTING & REPAIR Return to Section TOC Return to Section TOC Return to Section TOCReturn to Master TOC Return to Master TOC MAIN TRANSFORMER T1 VOLTAGE TEST continuedTROUBLESHOOTING & REPAIR Return to Section TOC Return to Section TOCReturn to Master TOC Return to Master TOC TROUBLESHOOTING & REPAIRMAIN TRANSFORMER T1 VOLTAGE TEST continued Return to Section TOC Return to Section TOCReturn to Master TOC Return to Master TOC TROUBLESHOOTING & REPAIRMAIN TRANSFORMER T1 VOLTAGE TEST continued Return to Section TOC Return to Section TOCFIGURE F.8 - CONTROL BOARD PLUG P1 LOCATION TROUBLESHOOTING & REPAIRPlug P1 PHASE ANGLE WINDING VOLTAGES MAIN TRANSFORMER T1 VOLTAGE TEST continuedReturn to Section TOC STATIC SCR/DIODE RECTIFIER BRIDGE TESTTROUBLESHOOTING & REPAIR Return to Section TOC Return to Section TOC Return to Section TOCto Master TOC STATIC SCR/DIODE RECTIFIER BRIDGE TEST continuedTROUBLESHOOTING & REPAIR to Section TOCReturn to Section TOC Return to Section TOC SCR ANODE REMOVE ANY INSULATING PAINT CATHODE SCRTROUBLESHOOTING & REPAIR STATIC SCR/DIODE RECTIFIER BRIDGE TEST continuedReturn to Section TOC ACTIVE SCR TESTTROUBLESHOOTING & REPAIR Return to Section TOC Return to Section TOC Return to Section TOCReturn to Master TOC ACTIVE SCR TEST continuedTROUBLESHOOTING & REPAIR Return to Section TOCReturn to Section TOC Return to Section TOC Return to Section TOC TROUBLESHOOTING & REPAIRACTIVE SCR TEST continued SCR ANODE REMOVE ANY INSULATING PAINT CATHODE SCRReturn to Master TOC TROUBLESHOOTING & REPAIRACTIVE SCR TEST continued Return to Section TOCTROUBLESHOOTING & REPAIR MAXIMUM OUTPUT SETTING - NO LOADSCOPE SETTINGS NORMAL OPEN CIRCUIT VOLTAGE WAVEFORMReturn to Section TOC Return to Section TOC Return to Section TOC TYPICAL OUTPUT VOLTAGE WAVEFORM - MACHINE LOADEDTROUBLESHOOTING & REPAIR SCOPE SETTINGSReturn to Section TOC Return to Section TOC Return to Section TOC TYPICAL SCR GATE VOLTAGE WAVEFORMTROUBLESHOOTING & REPAIR SCOPE SETTINGSReturn to Section TOC Return to Section TOC Return to Section TOC ABNORMAL OUTPUT VOLTAGE WAVEFORM - MACHINE LOADEDTROUBLESHOOTING & REPAIR SCOPE SETTINGSTROUBLESHOOTING & REPAIR INPUT CONTACTOR CR1 CLEANING/REPLACEMENTDESCRIPTION MATERIALS NEEDEDReturn to Section TOC to Section TOC TROUBLESHOOTING & REPAIRINPUT CONTACTOR CR1 CLEANING/REPLACEMENT continued FIGURE F.17 - INPUT CONTACTOR CLEANING AND REMOVALReturn to Section TOC FAN MOTOR AND BLADE REMOVAL AND REPLACEMENTTROUBLESHOOTING & REPAIR Return to Section TOC Return to Section TOC Return to Section TOCReturn to Master TOC Return to Master TOC FAN MOTOR AND BLADE REMOVAL AND REPLACEMENT continuedTROUBLESHOOTING & REPAIR Return to Section TOC Return to Section TOCReturn to Section TOC SCR/DIODE RECTIFIER ASSEMBLY REMOVAL AND REPLACEMENTTROUBLESHOOTING & REPAIR Return to Section TOC Return to Section TOC Return to Section TOCReturn to Section TOC to Section TOC SCR/DIODE RECTIFIER ASSEMBLY REMOVAL AND REPLACEMENT continuedTROUBLESHOOTING & REPAIR FIGURE F.19 - SCR/DIODE ASSEMBLY DETAILSMATERIALS NEEDED SCR REMOVAL AND REPLACEMENTTROUBLESHOOTING & REPAIR DESCRIPTIONTROUBLESHOOTING & REPAIR SCR REMOVAL AND REPLACEMENT continuedPROCEDURE SPECIAL INSTRUCTIONSReturn to Section TOC Return to Section TOC Return to Section TOC TROUBLESHOOTING & REPAIRSCR REMOVAL AND REPLACEMENT continued FIGURE F.22 - CLAMP ASSEMBLYReturn to Master Return to Master TOC Return to Master TOC TROUBLESHOOTING & REPAIRSCR REMOVAL AND REPLACEMENT continued Return to Section Return to Section TOC Return to Section TOCHOUSING TROUBLESHOOTING & REPAIRSCR REMOVAL AND REPLACEMENT continued FIGURE F.23 - HOUSING AND PRESSURE PAD FOR 5/8” WIDE LEAF SPRINGReturn to Section Return to Section TOC Return to Section TOC TROUBLESHOOTING & REPAIRSCR REMOVAL AND REPLACEMENT continued Removal and Replacement procedure toReturn to Section TOC MOUNTING OF STUD TYPE DIODES TO ALUMINUM HEAT SINKSTROUBLESHOOTING & REPAIR Return to Section TOC Return to Section TOC Return to Section TOCMaster TOC MOUNTING OF STUD TYPE DIODES TO ALUMINUM HEAT SINKS continuedTROUBLESHOOTING & REPAIR Section TOCReturn to Section TOC MAIN TRANSFORMER REMOVAL AND REPLACEMENTTROUBLESHOOTING & REPAIR Return to Section TOC Return to Section TOC Return to Section TOCReturn to Master TOC Return to Master TOC MAIN TRANSFORMER REMOVAL & REPLACEMENT continuedTROUBLESHOOTING & REPAIR Return to Section TOC Return to Section TOCReturn to Master TOC Return to Master TOC TROUBLESHOOTING & REPAIRMAIN TRANSFORMER REMOVAL & REPLACEMENT continued Return to Section TOC Return to Section TOCReturn to Section TOC TROUBLESHOOTING & REPAIRMAIN TRANSFORMER REMOVAL & REPLACEMENT continued Return to Section TOC Return to Section TOC Return to Section TOCReturn to Section TOC TROUBLESHOOTING & REPAIRMAIN TRANSFORMER REMOVAL & REPLACEMENT continued FIGURE F.28 - COIL LEAD PLACEMENTReturn to Master TOC Return to Master TOC TROUBLESHOOTING & REPAIRMAIN TRANSFORMER REMOVAL & REPLACEMENT continued Return to Section TOC Return to Section TOCReturn to Master Return to Master TOC Return to Master TOC TROUBLESHOOTING & REPAIRMAIN TRANSFORMER REMOVAL & REPLACEMENT continued Return to Section Return to Section TOC Return to Section TOCOutput Control Setting RETEST AFTER REPAIRTROUBLESHOOTING & REPAIR Input Volts/Phase/HertzReturn to Master TOC Return to Section TOC Return to Section TOC Return to Section TOCReturn to Section TOC Return to Master TOC Return to Master TOC Return to Master TOCReturn to Master TOC ELECTRICAL DIAGRAMSElectrical Diagrams Section Return to Master TOC Return to Master TOC Return to Master TOCReturn to Master Wiring Diagram Codes 10084, 10085ELECTRICAL DIAGRAMS Return to SectionMaster TOC Wiring Diagram CodeELECTRICAL DIAGRAMS Section TOCReturn to Section TOC Control PC Board G2629-1 LayoutELECTRICAL DIAGRAMS Return to Section TOC Return to Section TOC Return to Section TOCReturn to Master TOC Control PC Board G2629-1 SchematicELECTRICAL DIAGRAMS to Section TOCSNUBBER Snubber PC Board M15370-3 LayoutELECTRICAL DIAGRAMS M15370-3Snubber PC Board M15370-3 Schematic ELECTRICAL DIAGRAMS38J GENERAL INFORMATION Return to Master TOC Return to Section TOC Return to Section TOC Return to Section TOCReturn to Section TOC Return to Master TOC Return to Master TOC Return to Master TOC