Lincoln Electric SVM161-A Steel TIG Welding, Copper TIG Welding, Tips for AC TIG Welding

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B-10

OPERATION

B-10

 

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STEEL TIG WELDING

The TIG process is very effective for welding both car- bon steel and alloy steel, especially in applications requiring precision results. DC Electrode Negative Polarity is required. Since this process does not include the removal of impurities, proper cleaning and preparation of the edges is required.

FILLER MATERIAL:

The filler rods must deposit welds with mechanical characteristics appropriate for the application.

COPPER TIG WELDING

Since the TIG welding is a process characterized by high heat concentration, it is particularly suitable for welding materials with high thermal conductivity, like copper. As with steel, the DC Electrode Negative Polarity is employed, with argon as protective gas.

Considering the fluidity of molten copper, the use of backup support may prove useful.

FILLER MATERIAL:

In order to avoid the oxidation of the molten material, filler materials containing phosphorus, silicon or other deoxidating materials are typically used. The mechan- ical properties can also be improved through the use of silver.

TIPS FOR AC TIG WELDING

AC Inverter TIG power sources offer two significant advantages over conventional Silicon Controlled Rectifier (SCR) / transformer power sources:

1.The AC wave balance can be set to a higher per- centage electrode negative which minimizes tung- sten heating and erosion.

2.The AC frequency can be varied to "focus" the arc. Increasing the AC frequency above 60Hz will narrow the cone shape arc from the tungsten’s tip. Decreasing the AC frequency below 60Hz will broaden the cone shape arc from the tungsten’s tip.

The two above benefits can be used to maintain a tight focus of the arc for precise heat control and tight joint access. Because of the AC inverters abilities in these areas the following recommendations are made as a starting point:

•A 2% Thoriated tungsten is recommended instead of the Pure tungsten that is normally recommended for AC welding. Thoriated tungstens emit electrons eas- ier and therefore will improve starting.

•Sharpen the tungsten to a point. Normally it is rec- ommended to pre-ball a pure tungsten when AC welding with a conventional power source. However, the AC inverter with it’s extended AC bal- ance control minimized tungsten heating thus allow- ing for a pointed tungsten to be used.

•Set the AC Balance control to maximum 85% elec- trode negative. This can be reduced if the material welded is heavily oxidized, however starting at max- imum and adjusting to less is desired.

•Set the AC Frequency in the 100 to 120 Hz range. This is a "Sweet Spot" for most aluminum applica- tions.

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GTAW Process

Electrode Polarity

DC-

AC

Approximate Argon

 

Electrode Tip Preparation

Sharpened

Sharpened

Gas Flow Rate

 

 

 

 

 

 

C.F.H. (l/min.)

 

Electrode Type

 

 

 

 

 

 

 

 

 

 

 

 

EWTh-2, EWLa-1

EWTh-2, EWLa-1

 

 

Stainless

 

 

 

 

Electrode Size-in. (mm)

 

 

Aluminum

Steel

.010

(0.25)

Up to 15 A.

Up to 15 A.

3-8

(2-4)

3-8

(2-4)

.020

(0.50)

Up to 15 A.

Up to 20 A.

5-10

(3-5)

5-10

(3-5)

.040

(1.0)

Up to 80 A.

Up to 60 A.

5-10

(3-5)

5-10

(3-5)

1/16

(1.6)

Up to 150 A.

Up to 130 A.

5-10

(3-5)

9-13

(4-6)

3/32

(2.4)

Up to MAX. A.

Up to MAX. A.

13-17 (6-8)

11-15 (5-7)

1/8

(3.2)

X

X

15-23 (7-11)

11-15

(5-7)

Tungsten electrodes are classified as follows by the American Welding Society (AWS): +2% Thoria .......................EWTh-2 ...red

+1.5% Lanthana ...............EWLa-1 ...black

INVERTEC® V205-T AC/DC™

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Contents Invertec V205-T AC/DC Safety Invertec V205-T AC/DCElectric Shock can kill ARC Rays can burn Can be dangerousCylinder may explode Powered equipmentWelding Cutting Sparks can cause fire or If damaged ExplosionPrécautions DE Sûreté Sûreté Pour Soudage a L’ArcSafety Methods of Reducing Emissions Mains Supply Master Table of Contents for ALL Sections Table of Contents Installation Section Installation Operating Temperature Range Storage Temperature RangeTilting Select Suitable LocationStacking Environmental AreaReconnect Procedure Input Connections115V Input Attachment Plug Installation230V Input Engine Driven GeneratorWork Cable Connection Output ConnectionsOutput and GAS Connection for TIG Welding Figure A.1 Remote Control Connection Shielding GAS ConnectionInvertec V205-T AC/DC Table of Contents Operation Section General Description Safety InstructionsOperation Welding CapabilityOPERATIONB-3 Rear Control Panel Figure B.1Controls and Settings Figure B.2Step Diagram Local/Remote push button Selects the weldingTIG DC TIG AC SET UP Menu Indicator Parameter DefaultOutput Limitations Welding PolarityFigure B.7 Tips for AC TIG Welding Steel TIG WeldingCopper TIG Welding Filler MaterialAC TIG Welding Quick Start UP Protective GASDC TIG Welding Quick Start UP Table of Contents Accessories Section Compatible Equipment AccessoriesOptional Accessories Cable PlugsTable of Contents Maintenance Section Input Filter Capacitor Discharge Procedure MaintenanceSafety Precautions Routine Maintenance3MAINTENANCE Figure D.1 Major Component LocationsInvertec V205-T AC/DC 1TABLE of CONTENTS-THEORY of Operation Section E-1 Theory of Operation Input Board and BUS BoardMain Igbt Inverter Board Figure E.3 Main Igbt Inverter BoardOutput Module and Clamping Board Main TransformerOutput Module Transistor Board Superimposition BoardOutput Filter Board CONTROL/DISPLAY BoardHigh Frequency HF Board Insulated Gate Bipolar Transistor Igbt Operation Passive Active1TABLE of Contents Troubleshooting and Repair F-1 Troubleshooting and Repair HOW to USE Troubleshooting GuidePC Board Troubleshooting Procedures Electric Shock can killIgbt Perform the Input Filter Board Igbt Inverter Board Test Secondary Output Board Assembly Test See the Output Filter Troubleshooting and Repair External Diagnostics DisplayTroubleshooting and Repair Internal Diagnostics Figure F.2Internal Diagnostics LEDInvertec V205-T AC/DC Test Description Materials NeededInput Filter Capacitor Discharge Procedure Capacitor Solder Resistor PadsInput Filter Board Test Input Filter Board ProcedureInput Filter Board Test Input Filter Board Invertec V205-T AC/DC Main Igbt Inverter Board LOW Voltage Test Main Igbt Inverter Board LOW Voltage Test Figure F.6 Main Igbt Inverter Board LocationMain Igbt Inverter Board LOW Voltage Test LEDTP2 MF2 Figure F.7 Main Igbt Inverter Board LocationCONTROL/DISPLAY Board Test CONTROL/DISPLAY Board Test Figure F.8 CONTROL/DISPLAY Board LocationCN2 Figure F.9 CONTROL/DISPLAY Board LocationCN1 Figure F.10 Plugs CN1, CN2 & CN7BUS Board Test BUS Board Test Figure F.11 BUS Board LocationTable F.7 Plug CN4 Test Points Table F.5 Plug CN2 Test PointsTable F.6 Plug CN3 Test Points Table F.8 Plug CN7 Test PointsCN1 CN2 Main Inverter Board Power Factor Section Test Table F.11 Resistance Checks Main Inverter Board Power Factor Section TestTable F.10 Voltage Checks with 115 VAC Applied to Machine TP9 Gndpwr RL1 Invertec V205-T AC/DC Output Filter Board Test Output Filter Board Test Figure F.16 Output Filter Board LocationFigure F.17 Output Filter Board Plug Location Figure F.18 Output Filter Board Plug CN1Invertec V205-T AC/DC Secondary Output Board Assembly Test Secondary Output Board Assembly Test Figure F.19 Secondary Power Board LocationOFF GA-SA Mode Positive Meter Negative Meter Expected Reading Probe Table F.14 Output Diode Resistance CheckMain Inverter Board Welding Logic and Inverter Section Test Main Inverter Board Welding Logic and Inverter Section TestTable F.15 LED Function Table F.16 Feedback Voltage SignalsTable F.18 LED Check in Stick Mode Table F.17 Voltage Checks with 115 VAC Applied to MachineFigure F.22 Main Board Inverter Section TP9 Ground Power Invertec V205-T AC/DC Input Filter Board Removal and Replacement Input Filter Board Removal and Replacement Figure F.24 Input Filter Board LocationRV1 RV2 Invertec V205-T AC/DC Main Igbt Board Removal and Replacement Main Igbt Board Removal and Replacement Figure F.27 Main Igbt Board LocationRV1 RV2 CN4 RV3 RV4 CN5 RV5 RV7 RV6 Invertec V205-T AC/DC CONTROL/DISPLAY Board Removal and Replacement CONTROL/DISPLAY Board Removal and Replacement Figure F.29 CONTROL/DISPLAY Board LocationCN2 Invertec V205-T AC/DC Output Filter Board Removal and Replacement Removal and Replacement Figure F.32 Output Filter Board LocationPhillips Head Screws CN1 Output Diodes Removal and Replacement Output Diodes Removal and Replacement To Replace ANY of the Output Diodes D1, D2, D3 or D4Output Transistor Removal and Replacement Output Transistor Removal and Replacement Figure F.36 Output Transistor LocationPlug CN1 5mm Allen Bolts Invertec V205-T AC/DC Table of Contents Diagram Section ELECTriCaL DiaGramS
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