Lincoln Electric SVM132-A Circuit Protection, Avoiding Ground Lead Protector GLP Activation

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B-4

OPERATION

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CIRCUIT PROTECTION

FIELD CIRCUIT FUSE. This 1/2 amp slow blow fuse, located on the Relay PC board, protects the field cir- cuit. It will blow if the field shorts or if one of the field circuit components on the Relay PC board fails.

MOTOR THERMAL PROTECTION. The temperature sensing thermal protector mounted in the motor opens the relay circuit when the motor overheats because of excessive loading or frequent triggering. This protects the motor without nuisance tripping. The thermal pro- tector automatically resets itself after the motor cools sufficiently (may take 10-15 minutes). Reset time can be shortened by cooling the motor with an air hose or fan.

CIRCUIT BREAKER. The 5 amp circuit breaker locat- ed above the drive rolls normally trips only when an overload occurs because of excessive loading in the wire feed cable, or a defective motor or control com- ponent. After allowing a minute for cooling, push the reset button and weld. If it trips again, be sure the wire feed cable is clean and the proper size for the wire diameter being fed. If it still trips, look for a defective electrical component.

AVOIDING GROUND LEAD PROTECTOR (GLP) ACTIVATION

The frame of the LN-8 wire feed unit and the drive motor are grounded to the frame of the power source by a lead in the control cable. An overload protector prevents welding current from damaging this lead if the electrode circuit touches the wire feeder frame while the gun trigger is pressed.

When the protector is tripped, the welding contactor in the power source will not close when the gun trigger is pressed.

DO NOT allow the electrode to contact the case of the wire feeder or the uninsulated part of the wire reel stand when the gun trigger is activated.

Be sure that all work lead connections to the work make tight metal-to-metal contact.

DO NOT allow excess input cable or work cable to be placed closer than three feet from the wire feeder.

DO NOT coil excess input cable assembly or use a coiled assembly as shipped from the factory. Instead, loop the excess cable length back and forth in three to six foot straight lengths. Coiling the input cable results in a transformer action between the electrode conductor cable and the ground lead in the multiconductor control cable. This transformer action can cause a current to flow in the ground lead which will falsely activate the GLP circuit.

To reset the GLP circuit, press the white button above the drive motor and to the right of the circuit breaker.

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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 Electrode Diameter LN-8 with K303LN-8 with K377 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-14Cable Clamp Conductor Electrode Wire Reel Basecontrol Input Cable ConnectionsLN-8N and LN-8S LN-8NE and LN-8SEConnections to Wire Feeder Extension Tube ConnectorLocking ScrewFigure A.14 Wire Feeder Handle Installation SELF-TAPPING Screw Hinge HandleHandling Procedures GUN and Cable AssembliesLN-8S and LN-8SE Continuous Flux Feed Submerged ARC GeneralOperation Safety Instructions Controls and Their FunctionsConstant Current Controls 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 To Mount 10 to 44 lb 4.5 to 20 kg Spools 12 in./300 mm Diameter or 14 lb 6 kgInnershield Coils 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 GeneralK161 Mechanized Travel Power Pack K163 Undercarriage Requires K303, K377, or K378K178 Mounting Platform 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 Connector ReceptacleCircuit Applied Breaker 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 Black WhiteGreen Ground Yellow 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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