Lincoln Electric SVM169-A service manual Operating Steps, Welding in TIG Mode, Pulse TIG Control

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B-5

OPERATION

B-5

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8.PULSE TIG CONTROL – The Pulse TIG feature built into the Precision TIG 185 is simplified to be a single knob control which sets the Pulse Frequency over the peak pulses/sec. range of about 0.1 to 20 pulses per second:

Full CCW (min.) setting of the control knob shuts off Pulse TIG (0.0 pps).

Peak Pulse level is set by the Max. Output Control and the Remote Amptrol (if used).

Background Current level is typically optimized at a fixed 50% of Peak Pulse level setting.

Peak Pulse % On-time is typically optimized at a fixed50%.

A Green light "blinks" with each Peak Pulse to indi- cate the Pulse TIG Control setting before and during welding.

9.OVER TEMPERATURE LIGHT - If the welder overheats due to blocked air flow, high ambient air temperature, or exceeded duty cycle, an internal thermostat will open disabling the welding output and this yellow light will illuminate. The cooling fans will continue to run to cool the unit during this time. The light will go out when the unit cools and the thermostat resets. Once the light goes out, the machine will again become available to weld.

10.REMOTE RECEPTACLE – Provides for connec- tion of remote control and/or arc start switch only in TIG Mode: ( There is no remote output control capability when stick welding.

Plugging a remote current control (Amptrol) into this receptacle automatically switches the output control from the panel Max Output Control (See Item 5) to the remote control.

The connected remote control will then control the output current between the Min. range of the machine and the setting of the panel Max Output Control.

Switching Mode Switch (See Item 3) to Stick will automatically disable the connected remote con- trol and switch the output control back to the Max Output panel control.

11.ELECTRODE/GAS OUTPUT RECEPTACLE - This quick connect Twist-Mate receptacle provides electrical connection to the electrode holder and cable for Stick welding and a combined electrical and gas connection for the TIG torch when TIG welding.

12.WORK CABLE - This work cable is factory con- nected to the welder and is connected to the work piece to complete the welding circuit. Refer to

Machine Grounding and High Frequency Interference Protection in the Installation section of this manual for the proper procedure on ground- ing the work clamp and work piece to minimize high frequency interference.

OPERATING STEPS

WELDING IN TIG MODE

1.Connect the TIG torch and cable Twist-Mate quick connect plug to the Electrode/Gas output recepta- cle. This receptacle also contains an integral gas connection for the torch. Connect the work clamp to the work piece.

2.Set the TIG/STICK switch to “TIG”.

3.Set the Polarity Switch to DC- for welding steel or stainless steel; or to AC for welding aluminum.

4.Connect the Foot Amptrol to the Remote Control Connector.

5.Turn on the cylinder gas valve and adjust the flow regulator to obtain desired flow.

6.Turn the power switch to “ON”. NOTE: There will be a 15 second gas flow when the power is turned on.

7.Preset the Output Control on the control panel to the maximum desired amps, as read on the digital meter.

8.Depress the Foot Amptrol to energize the torch and establish an an arc with the work piece. The digital meter reads the actual amps while welding.

NOTE: When the TIG/STICK switch is set to “TIG”, depressing the remote control will start a 0.5 second gas pre-flow before energizing the TIG torch. When the remote control is released the TIG torch is de-ener- gized and gas flow will continue for the time set by the Post Flow Time control. When the polarity switch is set to DC, the TIG Arc Starter will turn on and off automat- ically to start and stabilize the arc. In AC the TIG Arc Starter will turn on with the output and remain on con- tinuously until the remote control is released.

PULSE TIG CONTROL

Use this knob to set the frequency or the number of pulses per second(pps), from 0.1pps to 20pps.

This setting adjusts heat output and bead shape for travel speed. Thinner plate that is welded with faster travel speed will require higher frequency than thick- er plate with slower travel speed. 2-3pps is a typical starting point.

PRECISION TIG 185

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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