Lincoln Electric SVM132-A service manual General Description, Power Input Circuits

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E-2

THEORY OF OPERATION

E-2

 

FIGURE E.1 – POWER INPUT CIRCUITS

 

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REMOTE￿

OUTPUT￿

CONTROL

 

#21

 

 

#75￿

 

 

 

 

 

 

WIRE FEED￿

#76￿

 

 

 

 

 

 

 

 

 

 

 

 

SPEED CONTROL

#77

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CIRCUIT￿

 

 

 

 

 

 

 

 

 

BREAKER

 

 

 

 

INPUT￿

 

#32

 

 

 

 

 

 

#32A

RECEPTACLE

#31

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

#2￿

 

 

 

 

 

 

 

 

 

 

 

&￿

 

 

 

2 OHMS

 

 

#4￿

 

 

 

 

 

 

 

 

 

 

 

￿

 

 

 

 

 

 

 

 

 

 

 

C￿

 

 

 

 

 

 

 

 

 

 

 

O￿

 

 

 

 

 

 

 

 

 

 

 

N￿

 

 

 

 

 

 

 

 

 

 

 

T￿

 

 

 

 

 

 

 

 

 

 

 

A￿

 

 

 

 

 

 

 

 

 

 

 

C￿

 

 

#531

 

 

T￿

 

 

 

 

 

 

 

 

 

 

 

O￿

 

 

 

 

 

 

 

 

 

 

 

R

 

 

 

 

 

 

 

 

 

 

 

CONTROL

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OPTIONAL￿

 

 

 

 

BURNBACK￿

 

 

 

 

BOARD

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

GLP

 

 

 

 

 

 

 

 

 

 

 

 

VARIABLE VOLTAGE￿

#567

ELECTRODE￿

BOARD

 

METER￿

 

SHUNT

 

 

 

 

 

 

 

 

 

 

CONTROL￿

ARMATURE

WIRE￿

THERMAL￿

 

FEED￿

CIRCUIT￿

BOARD

 

MOTOR

BREAKER

 

 

 

 

 

#3￿

2￿

A

FUSE

 

 

 

 

FIELD

RELAY￿

BOARD

GUN￿

CABLE￿

RECEPTACLE

 

 

 

 

 

 

 

 

REED￿

 

TRIGGER￿

WIRE￿

 

INTERLOCK

￿

 

FEED￿

 

SWITCH

 

TRANS.

 

SWITCH

 

 

SWITCH

 

 

 

 

 

 

 

 

 

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GENERAL DESCRIPTION

The LN-8 is a semiautomatic wire feeder designed for Innershield (FCAW) and gas metal arc processes with the appro- priate accessories. It is also suitable for constant voltage (CV) submerged arc welding processes. With the optional variable voltage board installed the LN-8 can be used with constant current (CC) procedures. The wire feed speed and welding power source output can be controlled from the LN-8.

receptacle, through the circuit breaker and 2 ohm resistor to the control board, the relay board, and the trigger trans- former.

The 24VAC developed at the trigger transformer is rectified on the relay board and applied to the gun trigger cir- cuit which controls the 1CR relay.

The 115VAC that is applied to the con- trol board is rectified and controlled by SCRs (See SCR Operation) and applied to the armature of the wire feed motor.

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POWER INPUT CIRCUITS

The relay board rectifies the 115VAC

 

 

and applies it to the field winding of the

The 115VAC is applied (usually from the wire feed motor.

welding power source) via the input

 

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

LN-8

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Contents LN-8 Semiautomatic Wire Feeder Safety LN-8Electric Shock can kill Welding Sparks can cause fire or explosion IiiPrécautions DE Sûreté Sûreté Pour Soudage a L’ArcMaster Table of Contents for ALL Sections Installation LN-8 with K377 Electrode DiameterLN-8 with K303 LN-8 with K378Table A.1 Work Lead Specifications Power Source ConnectionsLN-8N and LN-8NE Power Source Selection Switch Variable Voltage PC Board LN-8S and LN-8SE and Converted LN-8N and LN-8NEPower Source Connection Diagrams Table A.2 LN-8 Power Source Connection DiagramsSection TOC Installation TOC 9A-9 Figure A.5 Connection of LN-8 to R3S-250 and R3S-32510A-10 Figure A.6 Connection of LN-8 to DC-600Power Source To LN-8 Input Cable Plug Control Cable LN-8 for Same Polarity Operation LN-8 for Opposite Polarity Operation Shock Can KillFigure A.10 for Power Sources Other than Lincoln Electric 14A-14LN-8N and LN-8S Cable Clamp Conductor Electrode Wire Reel BasecontrolInput Cable Connections LN-8NE and LN-8SELocking Connections to Wire FeederExtension Tube Connector ScrewFigure A.14 Wire Feeder Handle Installation SELF-TAPPING Screw Hinge HandleLN-8S and LN-8SE Continuous Flux Feed Submerged ARC Handling ProceduresGUN and Cable Assemblies GeneralOperation Constant Current Controls Safety InstructionsControls and Their Functions Gouging SparksConstant Voltage Controls Current Controls VoltageCircuit Protection Avoiding Ground Lead Protector GLP ActivationWire Feed Rolls and Guide Tubes Figure B.3 Wire Feed Rolls and Guide Tube InstallationSetting for CV or CC Power Sources Voltage Power Source Welding with a ConstantMounting a 50 or 60 lb Coil Slots Coil ReelK363-P READI-REEL Adapter Wire Reel Loading K1524-1 Universal Wire Reel StandAdapter Innershield Coils To Mount 10 to 44 lb 4.5 to 20 kg Spools12 in./300 mm Diameter or 14 lb 6 kg READI-REELS a K438 READI-REEL Adapter Must be UsedFeeding Electrode to the LN-8NE or LN-8SE with Extension Feeding Electrode to the LN-8N or LN-8SBrass Blocks Hand Crank ARM Flux Tank Loading Slow Acceleration Starting Code 7926 and AboveAccessories Table C.1 LN-8 Wire Feeder Accessories GeneralK178 Mounting Platform K161 Mechanized Travel Power PackK163 Undercarriage Requires K303, K377, or K378 K58 Magnetic SeparatorReel Mounting Accessories Welding Guns Welding GUN Accessories Constant Current Conversion PartsLN-8 Maintenance Table of Contents Maintenance SectionRoutine Maintenance Periodic Maintenance Table of Contents Theory of Operation Section Theory of OperationPower Input Circuits General DescriptionGUN Trigger and 1CR Relay Contact Control Circuits Figure E.2 GUN Trigger and 1CR Contact Control CircuitsFuse Field 5E-5 SCR OperationApplied Later CYCLE, the SCR Output Is Decreased LN-8 Troubleshooting and Repair HOW to USE Troubleshooting Guide Return to Return to Section TOCTroubleshooting & Repair PC Board Troubleshooting ProceduresTroubleshooting Guide Problems SymptomsFunction Problems Transformer Test Perform the 1CR Relay Test Feeding Problems Welding Problems LN-8 Electrical Sequence of Operation Figure F.1 LN-8 Electrical Sequence of Operation Trigger Transformer Test Test DescriptionTrigger Transformer Test Internal Voltage Test Circuit Applied Breaker ConnectorReceptacle Control BoardInternal Voltage Test Table F.1 Voltage Test Points1CR Relay Test 1CR Relay Test 1CR Relay Test Table F.2 Relay Test Terminal ConnectionsDrive Motor Test Drive Motor Test Figure F.6 GUN Terminal Jumper Locations 1CRTo further check the drive motor Table F.3 Drive Motor Test PointsPotentiometer Replacement Repair Procedure Circuit Breaker Replacement Ground Lead Protector Switch Mount Flatwasher Lockwasher NUT Retaining NUTGround Lead Protector Push Button Switch Replacement Ground Lead Protector Push Button Trigger Transformer Replacement Relay PC Board Roundhead Screw Insulation Sheet Trigger Transformer NUTPC Board Replacement Figure F.10 PC Board Locations Control PC Board Variable Voltage PC Board Relay PC BoardRelay Board Removal Control PC Board Replacement Wire Drive Assembly and Component Replacement Green Ground Yellow BlackWhite Blue TWOShunt #568 #567Motor Gearbox Insulation Sheet Mounting PlateTOC Retest After Repair Electrical Diagrams LN-8N, -8NE, -8S, and -8SE Wiring Diagram Connection Schematic Source Power to WorkOperating Schematic 1CR Wire Feed Motor FieldControl Board L5767 Schematic Variable Voltage Board L5039 Schematic Control Board L5767 Layout ControlVariable Voltage Board L5039 Layout SVM Error Reporting Form
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