Lincoln Electric SVM169-A service manual Theory of Operation Section, Section E

Page 31

Return to Master TOC

Return to Master TOC

Return to Master TOC

Return to Master TOC

Section E-1

TABLE OF CONTENTS

Section E-1

 

- THEORY OF OPERATION SECTION -

 

 

 

 

Theory of Operation

Section E

General Description

E-2

Input Power Circuit

E-2

Output Rectification and Feedback Control

E-3

High Voltage/High Frequency Circuit

E-4

DC Welding Output

E-5

AC Welding Output

E-6

SCR Operation

E-7

Protective Circuits

E-8

Thermal Protection

E-8

Overload Protection

E-8

FIGURE E.1 – PRECISION TIG 185 BLOCK LOGIC DIAGRAM

 

 

 

 

 

BY-PASS

 

 

 

 

 

BOARD

 

 

POLARITY

 

WORK

 

 

 

 

 

 

SWITCH

 

ELECTRODE

 

 

 

 

 

 

MAIN

 

 

 

HI-FREQUENCY

 

TRANSFORMER

 

 

 

TRANSFORMER

INPUT

 

 

 

 

 

POWER

 

 

 

 

 

SWITCH BYPASS

 

 

 

C

ASBLY

 

 

 

 

 

 

 

 

H

 

H1

 

 

 

 

AC

DC+

 

O

 

X1

 

 

 

K

 

 

SCR

 

 

 

BRIDGE

 

E

 

H2

 

 

SHUNT

HIGH VOLTAGE

 

X2

 

 

 

AC

DC-

TRANSFORMER

 

H3

 

 

 

 

F

CIRCUIT

 

 

 

 

 

 

 

 

 

E

 

 

 

 

 

E

 

 

 

 

 

D

 

 

 

 

 

B

 

 

 

 

 

A

 

 

 

 

 

C

 

 

 

 

 

K

 

 

18VAC

 

 

 

115VAC

 

18VAC

 

CONTROL

POWER

 

 

 

 

 

FAN

115VAC

 

BOARD

"ON"

 

DIGITAL

 

 

 

 

 

DISPLAY

 

 

 

 

 

MODE

 

 

 

 

 

SWITCH

 

REMOTE

 

 

THERMO-

 

 

RECEPTACLE

THERMAL

GAS

OUTPUT

 

 

STATS

 

 

LIGHT

VALVE

CONTROL

 

 

 

AUTO

PULSE TIG

STICK

AC

PULSE POSTFLOW

BALANCE FREQ. LED

LED

BALANCE

CONTROL CONTROL

LED

LED

 

CONTROL

 

X

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Image 31
Page 30 Page 32
Contents Precision TIG Safety Electric Shock can kill Welding Sparks can cause fire or explosion SafetySûreté Pour Soudage a L’Arc Précautions DE SûretéMaster Table of Contents for ALL Sections Installation Section Table of ContentsInput Single Phase only InstallationK2345-2 Input at Rated Output Model Height Width Depth WeightSelect Suitable Location Safety PrecautionsInput Connections TIG Torch Connection Input Reconnect ProcedureOutput Connections Connections for TIG Gtaw WeldingWork Cable Connection Remote Control ConnectionShielding GAS Connection Precision TIG Section B Operation SectionOperation Recommended Processes and Equipment Product DescriptionControl Functionality Controls and SettingsOperating Steps Welding in TIG ModePulse TIG Control Benefits of the Precision TIG 185 Design Remote Control OperationRecommended Electrode Amperage Ranges Precision TIG Welding in Stick ModePrecision TIG Accessories Section Factory Installed Options AccessoriesTable C.1 K2348-1 Under-Storage Cart Field Installed OptionsPrecision TIG Section D Maintenance SectionRoutine and Periodic Maintenance MaintenanceSpark GAP Adjustment Figure D.2 Location of Maintenance Components Return to Section TOC Section E Theory of Operation SectionTheory of Operation Input Power CircuitGeneral Description Figure E.3 Control Board and Output Feedback Control Output Rectification Feedback ControlFigure E.4 High Voltage/High Frequency Circuit High Voltage / High Frequency CircuitFigure E.5 DC Welding Current Generation DC Welding OutputFigure E.6 AC Square Wave Welding Current Generation AC Welding OutputFigure E.7 SCR Operation SCR OperationThermal Protection Protective CircuitsOverload Protection Section F Troubleshooting & Repair SectionHigh Voltage / High Frequency can damage test equipment Troubleshooting & RepairWorkstations PC Board Troubleshooting ProceduresCourse of Action Problems Possible Areas Recommended SymptomsPossible Areas Recommended Symptoms Problems Possible Areas Check the welding cables and or TIG Mode Problems Troubleshooting & Repair TIG Welding Problems Problems Possible Areas Electric Shock can Problems Possible Areas Recommended Symptoms Stick Welding Problems Test Description High Frequency Circuit Disable ProcedureFigure F.1 Spark GAP Assembly ProcedureT1 Transformer Test T1 Transformer Test Test ProcedurePrimary Windings Primary Voltages Return to Section Section TOCPrecision TIG Static SCR Test Static SCR Test Assembly Removal and Replacement Precision TIG Active SCR Test Active SCR Test Figure F.6 SCR Gate Locations Precision TIG Scope Settings AC TIG ModeNormal Open Circuit Voltage Waveform DC TIG Mode AC Stick Mode DC Stick Mode Machine Loaded to 180 Amps AT 16VDC Typical Output Voltage Waveform Machine LoadedDC TIG Mode Machine Loaded to 180 Amps AT 26VDC DC Stick Mode 50 V/Div Precision TIG SCR Bridge Assembly Removal and Replacement Procedure Troubleshooting and RepairProcedure SCR Bridge AssemblyFront Panel Mounting Screws Figure F.9 Plug J2 on Control Board 42TROUBLESHOOTING & REPAIRF-42Replacement Procedure 43TROUBLESHOOTING & REPAIRF-43Precision TIG Polarity Switch Removal and Replacement Procedure Removal Procedure Polarity SwitchReplacement Procedure Precision TIG High Voltage Transformer Removal and Replacement Procedure Transformer Secondary Leads Precision TIG High Voltage TransformerFigure F.12 High Voltage Transformer Mounting Insulators Precision TIG Nutdriver Wrench Wire cutters Perform the SCR Bridge Assembly Removal Procedure Assembly Replacement Procedure Precision TIG Recommended Meters for Machine Output Tests Troubleshooting and RepairRetest After Repair Input Idle AmpsPrecision TIG Electrical Diagrams Section Precision TIG Wiring Diagram Entire Machine G4549G4588 Schematic Entire Machine G4588Schematic Control PC Board G4550-1B4-1 Schematic Control P.C. Board G4550-1B4-2 Schematic Control P.C. Board G4550-1B4-3 G4551 PC Board Assembly Control G4551-1SVM Error Reporting Form
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