Lincoln Electric SVM100-A service manual TIG Welding Sequence Operation 4-STEP Mode

Page 23

OPERATION

B-10

Return to Section TOC

Return to Section TOC

Return to Section TOC

Return to Section TOC

Return to Master TOC

Return to Master TOC

Return to Master TOC

Return to Master TOC

9.Set the Afterflow time with the Seconds Up/Down keys. Afterflow time provides shielding gas flow (and cooling water, if used) after the weld. Use short Afterflow times with low currents and small tungstens, use long afterflow times at high output currents with large tungstens.

10.Press and release the Arc Start Switch, and set the gas flow meter. The welder is now ready for welding.

11.Position the tungsten electrode at the start of the weld at a 65° to 75° angle with the horizontal so that the electrode is approximately 1/8” (4mm) above the work piece. Press the Arc Start Switch. This opens the gas and water valves to automati- cally purge air from the hose and torch. After a 0.5 second preflow time, the high frequency becomes available to strike the arc.

12.Hold the Arc Start Switch or Amptrol down until an arc is established. If using an Amptrol, read the section on Hand and Foot Amptrol Operation. Release the Arc Start Switch or Amptrol to stop the arc and start the Afterflow timer. After the Afterflow time has expired, the gas and water valves will close. To make another weld, repeat steps 11 and 12.

TIG WELDING SEQUENCE OF

OPERATION (4-STEP MODE)

TIG 4-Step Mode funcitons like a trigger interlock, making it unnecessary to hold down the Arc Start Switch during welding. By depressing the Arc Start Switch a first time, the arc will start at a low current (step 1). By releasing the Arc Start Switch (step 2) the output ramps up to welding current. Depressing the Arc Start Siwtch a second time (step 3) initiates a welding current downslope. Releasing the Arc Start Switch (step 4) stops the arc. Hence the name “4-Step Mode”

1.Connect an Arc Start Switch to the Remote Receptacle.

2.Turn the welder, gas supply and water supply (if so equipped), on. The Control Panel Display and red lights will illuminate when the power is on.

3.Select the TIG 4-Step Weld Mode.

4.Select the Local current control. Set the output current using the Amps Up/Down keys. The output current setting will be displayed on the Ammeter.

5.Select Continuous High Frequency if welding with AC polarity, or Start Only High Frequency if welding with DC- polarity. High Frequency Off can be used for scratch start welding.

6.Select AC or DC- electrode polarity. See Table B.1.

7.If welding with AC polarity, select Auto Balance™. This gives the optimum ratio between cleaning and penetration, automatically adjusted for the output current. If manual adjustment of the AC Wave Balance is desired, select Manual Balance, and adjust the wave balance with the Cleaning and Penetration keys. See the Advanced Features section for more information on setting and using the AC Wave Balance.

8.Select TIG Pulser On or Off. If the TIG Pulser is on, adjust the pulse frequency with the Pulses Per Second Up/Down keys. See the Advanced Features section for more information on setting and using the TIG Pulser.

9.Set the Afterflow time with the Seconds Up/Down keys. Afterflow time provides shielding gas flow (and cooling water, if used) after the weld. Use short Afterflow times with low currents and small tungstens, long afterflow times at high output currents with large tungstens.

10.Press and release the Arc Start Switch, and set the gas flow meter. The welder is now ready for welding.

11.Position the tungsten electrode at the start of the weld at a 65° to 75° angle with the horizontal so that the electrode is approximately 1/8” (4mm) above the work piece. Press the Arc Start Switch. This opens the gas and water valves to automatically purge air from the hose and torch. After a 0.5 second preflow time, the high frequency becomes available to strike the arc.

12.Hold the Arc Start Switch down until an arc is established. The arc will start at a low current value. Release the Arc Start Switch. At this point, the Square Wave TIG 255 will quickly ramp up to the welding current, and the weld will continue indefinitely. Press the Arc Start Switch a second time to initiate a 5-second downslope. The current will go down to a crater fill current that is equal to 25% of the welding current. Release the Arc Start Switch to stop the arc and start the Afterflow timer. After the Afterflow time has expired, the gas and water valves will close. To make another weld, repeat steps 11 and 12.

SQUARE WAVE TIG 255

Image 23
Contents Square Wave TIG Fumes and Gases can be dangerous SafetyElectric Shock can kill ARC Rays can burnWelding 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 InstallationStacking Safety PrecautionsHigh Frequency Interference Protection Select Suitable LocationInput Supply Connections Input ConnectionsGround Connection TIG Torch Connection Reconnect ProcedureOutput Connections Stick Electrode Cable Connection Table A.1Operation Section Fumes and Gases OperationOperating Instructions General WarningsSection TOC Coolant Tion Output Polarity Do not Switch AC & DC Recti Fier Power SourceWhile Weld ING TIG Gtaw Single Phase Work ConnecRecommended Processes and Equipment Design Features AdvantagesOperational Features and Controls General DescriptionLimitations Welding CapabilityControl Panel Keys Controls and SettingsLoad Case Front ControlsTIG Welding Guidelines Accessory Operation TIG WeldingTable B.1 Recommended Polarity Settings for TIG Welding Hand and Foot Amptrol Welding OperationSquare Wave TIG 255 12/95 TIG Welding Sequence Operation 2-STEP ModeTable B.2 Typical Current Ranges 1 for Tungsten Electrodes TIG Welding Sequence Operation 4-STEP Mode AC Wave Balance and Auto Balance Auxiliary PowerAdvanced TIG Welding Features ALL MachinesOverload Protection Square Wave TIG Accessories Section Undercarriage Function AccessoriesOptions / Accessories Installation of Field Installed OptionsMaintenance Section Safety Precautions MaintenanceMaintenance Routine and Periodic MaintenanceFigure 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 Recommended Course of Action Problems SymptomsPossible Areas of Misadjustments 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 LocationsMaterials Needed Control Transformer T2 Voltage TestTest Description 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 ModeMachine Loaded to 200 Amps AT 46 VAC AC TIG Mode Auto Balance onMachine Loaded to 50 Amps AT 26VAC 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 Recommended Meters for Machine Output Tests Retest After RepairInput Idle Amps 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