Lincoln Electric SVM 119-A service manual Operating Steps, Setting Idle Roll Pressure

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B-7

OPERATION

B-7

 

 

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SETTING IDLE ROLL PRESSURE

The idle roll pressure thumb screw is set at the factory backed out 2-1/2 turns from full pressure. This is an approximate setting. The optimum idle roll pressure varies with type of wire, wire diameter, surface condi- tions, lubrication, and hardness. As a general rule, hard wires may require greater pressure, and soft, or aluminum wire, may require less pressure than the fac- tory setting. The optimum idle roll setting can be deter- mined as follows:

1.Push the end of gun against a solid object that is electrically isolated from the welder output.

2.Press the gun trigger for several seconds.

a.If the wire "birdnests", jams, or breaks at the drive roll, the idle roll pressure is too great. Back the thumb screw out 1/2 turn, run new wire through gun, and repeat steps 1 and 2.

b.If the drive roll slips, loosen the thumb screw on the conductor block and pull the gun cable forward about 6" (15 cm). There should be a slight waviness in the exposed wire. If there is no waviness, the pressure is too low. Tighten the thumb screw 1/4 turn, reinstall the gun cable, and repeat steps 1 and 2.

OPERATING STEPS

WARNING

Before operating the machine, be sure you have all the materials needed to perform the work. Be sure you are familiar with and have taken all possible safety precautions before starting the work. It is important that you follow these operating steps each time you use the machine.

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STARTING THE WELDER

1.Turn the POWER switch to ON. This illuminates the red LED pilot light.

2.Select the correct voltage and wire speed for the welding process required.

3.Operate the gun trigger for welder output and to energize the wire feeder motor.

NOTE: When the POWER SWITCH is ON, the fan motor is thermostatically controlled to provide cooling for the transformer and other components only when the machine needs cooling. When the machine does not require fan cooling the fan does not run, such as when first turned on, when welding at low current, or at low duty cycle procedures.

CHANGING RUN-IN MODE

FAST OR SLOW RUN-IN MODE

SELECTION

The WIRE-MATIC 255 is factory set for fast run-in mode where the wire feed will accelerate directly to the preset wire feed speed when the gun trigger is closed.

Slow run-in mode may also be selected, where it will initially feed wire at 50 IPM until output current is sensed or for 2.0 seconds, whichever occurs first. After which it will accelerate to the preset wire feed speed.

INSTRUCTIONS TO ENTER SLOW RUN-IN MODE

1.Turn power OFF on front panel of Wire-Matic 255.

2.Turn the wire feed speed dial to minimum, fully counterclockwise.

3.With the gun trigger closed, turn the power ON at the front panel of the Wire-Matic 255.

4.The gas solenoid will actuate two times to signal that the unit has entered the slow run-in mode (the gun trigger need only be closed until the first gas solenoid actuation is heard).

INSTRUCTIONS TO ENTER FAST RUN-IN MODE

1.Turn power OFF on front panel of Wire-Matic 255.

2.Turn the wire feed speed dial to maximum, fully clockwise.

3.With the gun trigger closed, turn the power ON at the front panel of the Wire-Matic 255.

4.The gas solenoid will actuate four times to signal that the unit has entered the fast run-in mode (the gun trigger need only be closed until the first gas solenoid actuation is heard).

WIRE-MATIC 255

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Contents WIRE-MATIC Safety Depends on YouARC Rays can burn SafetyElectric Shock can kill Fumes and Gases can be dangerousCylinder may explode if damaged Welding Sparks can cause fire or explosionIii Electric and MAG- Netic FieldsMay be dangerous Précautions DE Sûreté Sûreté Pour Soudage a L’ArcWIRE-MATIC Table of Contents Table of Contents Installation Table of Contents Installation SectionTechnical Specifications Wire-Matic-255 Input Connections Safety PrecautionsSelect Proper Location StackingFuse and Wire Sizes Connect Shielding GAS Reconnect Procedure Figure A.4 Input Gas Supply ConnectionsFigure A.5 Reconnect Diagram For 208/230/1/60 Machines Connect Output Components ConnectionsWire Size Conversion Parts GUN and Cable InstallationWIRE-MATIC Table of Contents Operation Section OperationWELDING, Cutting Safety InstructionsGeneral Description Design Features Advantages Recommended Processes and EquipmentDuty Cycle Amps Volts Machine CapabilityLimitations Controls and Settings Figure B.1 Operator ControlsUsing the Wire Drive Roll Figure B.2 Wire Reel LoadingFeeding Electrode Setting Idle Roll Pressure Operating StepsMaking a Weld WIRE-MATIC Accessories Table of Contents Accessories SectionK672-1 Spool GUN Adapter KIT OPTIONS/ACCESSORIESMagnum GUN Connection KIT Optional K466-6 Making a Weld with the Spool GUN Adapter K672-1 Installed Timer KIT K585-1 Timer KIT Installation Optional K585-1K468 8 Spool Adapter Drive Roll Kits64 1.2mm Aluminum Feeding KIT K673-1 K363P READI-REEL AdapterDual Cylinder Mounting KIT K671-1 Maintenance Table of Contents Maintenance SectionRoutine and Periodic Maintenance Perform the following dailyMaintenance Drive Rolls and Guide Tubes Cable CleaningContact TIP and GAS Nozzle Installation GUN Tubes and NozzlesLiner Removal Replacement Figure D.2 Liner maintenanceGUN Handle Disassembly To open up the handleDescription English Size Metric Size WIRE-MATIC Table of Contents Theory of Operation Section Theory of OperationInput Line Voltage and Main TransformerOutput Rectification Feedback ControlConstant Voltage Output Figure E.4 Constant Voltage OutputWire Drive Motor FeedbackThermal Protection SCR Operation Figure E.6 SCR OperationWIRE-MATIC Troubleshooting & Repair Table of Contents Troubleshooting & Repair SectionHOW to USE Troubleshooting Guide Recommended Course of ActionBoard can be dam- aged by static electricity PC Board Troubleshooting ProceduresElectric Shock can kill Main Transformer Rectifier Assembly Test To Section TOC SCR Rectifier Perform the Wire Drive Motor Liquid elec Trolyte in these capacitors isPerform the Output Rectifier Materials Needed Main Transformer TestTest Description Main Transformer Test Test Procedure ON/OFF Power Switch will be hot during these testsLead Plug Location Static SCR Rectifier Assembly Test Leads Figure F.4 SCR 1 Test Points Active SCR Rectifier Assembly Test Leads Figure F.7 SCR Tester Circuit SCR connectionsWire Drive Motor and Tachometer Feedback Test Wire Drive Motor and Tachometer Feedback Test Test Procedure Test for Supply Voltage to Tachometer Test for Feedback Voltage to the Control BoardScope Settings Normal Open Circuit Voltage WaveformMachine Loaded to 250 Amps AT 26 VDC Scope Settings Typical Output Voltage Waveform Machine LoadedMachine Loaded to 220 Amps AT 22 VDC Scope Settings Troubleshooting & Repair Typical SCR Gate Voltage Waveform Control PC Board Removal and Replacement Removal and Replacement ProcedureRemoval and REPLACE- Ment Procedure Wire Drive Assembly Removal and Replacement Procedure Figure F.11 Wire Drive Assembly RemovalSCR Output Rectifier Removal & Replacement Right side heat sink See Figure F.14 Disconnection Heat Sink LeadCapacitor Bank Removal and Replacement Bank Removal Replacement ComponentsMain Transformer Removal and Replacement Power Switch FAN Motor and FAN Removal and Replacement FAN Motor and FAN Removal and Replacement Procedure Figure F.16 Fan Motor and Fan Removal ComponentsTroubleshooting & Repair Input Volts/Hertz Wire Speed RangeOpen Circuit Voltage 230/60 375WIRE-MATIC Table of Contents Electrical Diagrams Section WIRE-MATIC Electrical Diagrams Wiring Diagram 208/230 CodeWire Matic 255 230 / 460 Wiring Diagram 230/460/575 CodeControl PC Board G2803 Schematic Wirematic 255 Control Control PC Board G2803 Layout