Lincoln Electric SVM100-A Theory of Operation Section, Power Supply Block Logic Diagram

Page 33

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TABLE OF CONTENTS

Section E

- THEORY OF OPERATION SECTION -

 

 

 

Theory of Operation Section

Section E

Power Supply Operation

E-1 - E-5

Input Line Voltage and Main Transformer

E-1

Output Rectification and Feedback Control

E-2

High Voltage / High Frequency Circuit

E-3

DC Welding Output

E-4

AC Welding Output

E-5

SCR Operation

E-6

Thermal Protection

E-7

 

 

POWER SUPPLY BLOCK LOGIC DIAGRAM

 

 

 

 

POLARITY

 

 

BY-PASS

 

 

 

 

 

 

BOARD

 

 

 

 

SWITCH

 

 

 

 

 

 

 

 

WORK

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

HI-FREQ

 

 

 

 

 

 

 

 

TRANSFORMER

LINE

 

 

 

 

 

 

 

ELECTRODE

MAIN

 

 

 

 

 

 

 

SWITCH

 

 

 

 

 

 

 

TRANSFORMER

 

 

 

 

 

 

 

R

X2

 

AC

DC+

 

 

 

E

 

SHUNT

 

 

 

 

SCR

 

 

C

 

 

 

 

 

 

 

 

 

BRIDGE

 

 

 

O

 

 

 

 

 

 

 

 

 

 

 

 

 

 

N

 

 

 

 

 

 

 

 

N

 

 

 

 

 

 

 

 

E

X1

 

AC

DC-

 

 

 

C

 

 

CHOKE

 

 

T

 

 

 

 

 

 

 

 

SIGNALSGATE

 

 

 

 

 

 

POWER

 

 

 

 

 

 

FEEDBACK

 

 

 

 

 

 

 

 

FACTOR

 

 

 

 

 

 

 

 

CAPACITORS

 

 

 

 

 

 

 

 

 

 

 

ARC START

 

 

LCD DISPLAY

 

 

 

 

 

 

 

 

 

115VAC

PROTECTION

115 VAC

CONTROL

KEYPAD

FAN

 

 

 

SNUBBER

 

GATE SIGNALS

BOARD

 

LED

 

 

BOARD

 

 

BOARD

 

 

 

 

 

 

 

 

 

 

 

 

HI-FREQ

 

 

KEYPAD

 

 

 

 

 

115 VAC

 

 

 

 

115

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VAC

 

 

24 VAC

 

 

 

 

 

 

CONTROL

18 VAC

 

 

 

115 VAC

 

 

TRANSFORMER

 

 

 

 

 

16 VAC

 

 

 

 

 

 

 

 

 

RECEPTACLE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

115 VAC

 

HIGH VOLTAGE

HIGH FREQUENCY SPARK

 

 

 

TRANSFORMER

 

REMOTE

 

 

 

 

 

 

 

 

 

CIRCUIT

 

 

 

RECEPTACLE

 

 

 

 

 

 

 

 

 

 

 

 

NOTE: On subsequent pages areas of this diagram that are the topic of discusstion are shown in white, other portions of the circuit are shaded.

SQUARE WAVE TIG 255

Page 32 Page 34
Image 33
Page 32 Page 34
Contents Square Wave TIG Electric Shock can kill SafetyARC Rays can burn Fumes and Gases can be dangerousWelding Sparks can cause fire or explosion Cylinder may explode if damagedMay be dangerous Electric and Magnetic FieldsSûreté Pour Soudage a L’Arc Précautions DE SûretéMaster Table of Contents for ALL Sections Installation Section Table of ContentsTechnical Specifications Square Wave TIG InstallationHigh Frequency Interference Protection Safety PrecautionsSelect Suitable Location StackingInput Connections Ground ConnectionInput Supply Connections Reconnect Procedure Output ConnectionsTIG Torch Connection Stick Electrode Cable Connection Table A.1Operation Section Operating Instructions OperationGeneral Warnings Fumes and GasesSection TOC While Weld ING TIG Gtaw Single Phase Polarity Do not Switch AC & DC Recti Fier Power SourceWork Connec Coolant Tion OutputOperational Features and Controls Design Features AdvantagesGeneral Description Recommended Processes and EquipmentLimitations Welding CapabilityControl Panel Keys Controls and SettingsLoad Case Front ControlsTable B.1 Recommended Polarity Settings for TIG Welding Accessory Operation TIG WeldingHand and Foot Amptrol Welding Operation TIG Welding GuidelinesTIG Welding Sequence Operation 2-STEP Mode Table B.2 Typical Current Ranges 1 for Tungsten ElectrodesSquare Wave TIG 255 12/95 TIG Welding Sequence Operation 4-STEP Mode Advanced TIG Welding Features Auxiliary PowerALL Machines AC Wave Balance and Auto BalanceOverload Protection Square Wave TIG Accessories Section Options / Accessories AccessoriesInstallation of Field Installed Options Undercarriage FunctionMaintenance Section Maintenance MaintenanceRoutine and Periodic Maintenance Safety PrecautionsFigure D.1 General Assembly Exploded View Square Wave TIG Theory of Operation Section Power Supply Block Logic DiagramInput Line Voltage and Main Transformer Theory of OperationOutput Rectification and Feedback Control High Voltage / High Frequency Circuit DC Welding Circuit DC Welding OutputAC Welding Circuit AC Welding OutputSCR Operation Square Wave TIG SCR OperationThermal Protection Troubleshooting & Repair Section HOW to USE Troubleshooting Guide 1TROUBLESHOOTING & RepairPC Board Troubleshooting Procedures Troubleshooting & RepairOutput Problems Troubleshooting Guide12/95 Square Wave TIG Troubleshooting & Repair Problems Symptoms Possible Areas of MisadjustmentsRecommended Course of Action Function Problems Troubleshooting Guide Troubleshooting & Repair TIG Mode Problems Troubleshooting & Repair Troubleshooting Guide TIG Welding Problems Troubleshooting & Repair Stick Welding Problems Figure F.1 Control Board Connectors PC Board Connector LocationsControl Transformer T2 Voltage Test Test DescriptionMaterials Needed Control BOX Test ProcedureFigure F.4 Control Board and Transformer Control Transformer T2 Voltage TestPROTECTION/SNUBBER Board Continuity Test PROTECTION/SNUBBER Board Continuity Test Table F.6 Square Wave TIG Figure F.6 PROTECTION/SNUBBER Board Test PointsARC Start Trigger Circuit Test ARC Start Trigger Circuit Test Figure F.9 PROTECTION/SNUBBER Board Test Points Static SCR Test Figure F.11 Protection Board Plug Locations Static SCR TestActive SCR Test Figure F.13 PROTECTION/SNUBBER Board Plug Locations Active SCR TestSilicon Controlled Rectifier Test Battery TestScope Settings Normal Open Circuit Voltage Waveform DC Stick ModeNormal Open Circuit Voltage Waveform AC Stick Mode Normal Open Circuit Voltage Waveform DC TIG Mode Normal Open Circuit Voltage Waveform AC TIG Mode Machine Loaded to 200 Amps AT 50 VDC Typical Output Voltage Waveform Machine Loaded DC TIG ModeAC TIG Mode Auto Balance on Machine Loaded to 50 Amps AT 26VACMachine Loaded to 200 Amps AT 46 VAC Typical SCR Gate Voltage Waveform Volts 5msVolts 2ms Troubleshooting & Repair Tools Required FAN Motor and Blade RemovalFAN Motor and Blade Removal Materials Required SCR Heat Sink Assembly RemovalSCR Heat Sink Assembly Removal Retest After Repair Input Idle AmpsRecommended Meters for Machine Output Tests Figure F.16 Transformer Lead Test Points Retest After Repair cont’dElectrical Diagrams Electrical Diagrams PTC1,PTC2 THERMISTOR-PTC,56 OHMS,90MA Control Board G2150Control Board G2150 cont’d Square Wave TIG PROTECTION/SNUBBER Board L9255 CAPACITOR-CEMO,4700P,50V,10% Square Wave TIG Wiring Diagram Square Wave TIG 6 a 0 a 7 a 8 a 3 C Machine Schematic Square Wave TIGA C C T G2150Y P a D Control Board Schematic Square Wave TIG 255 cont’d G2150PROTECTION/SNUBBER Board Schematic Square Wave TIG 255 L9255 Keypad LED Board Square Wave TIG 255 L9212
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