Lincoln Electric SVM100-A service manual Cylinder may explode if damaged

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SAFETY

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WELDING SPARKS can cause fire or explosion.

4.a. Remove fire hazards from the welding area. If this is not possible, cover them to prevent the welding sparks from starting a fire. Remember that welding sparks and hot

materials from welding can easily go through small cracks and openings to adjacent areas. Avoid welding near hydraulic lines. Have a fire extinguisher readily available.

4.b. Where compressed gases are to be used at the job site, special precautions should be used to prevent hazardous situations. Refer to “Safety in Welding and Cutting” (ANSI Standard Z49.1) and the operating information for the equipment being used.

4.c. When not welding, make certain no part of the electrode circuit is touching the work or ground. Accidental contact can cause overheating and create a fire hazard.

4.d. Do not heat, cut or weld tanks, drums or containers until the proper steps have been taken to insure that such procedures will not cause flammable or toxic vapors from substances inside. They can cause an explosion even though they have been “cleaned”. For information, purchase “Recommended Safe Practices for the Preparation for Welding and Cutting of Containers and Piping That Have Held Hazardous Substances”, AWS F4.1 from the American Welding Society (see address above).

4.e. Vent hollow castings or containers before heating, cutting or welding. They may explode.

4.f. Sparks and spatter are thrown from the welding arc. Wear oil free protective garments such as leather gloves, heavy shirt, cuffless trousers, high shoes and a cap over your hair. Wear ear plugs when welding out of position or in confined places. Always wear safety glasses with side shields when in a welding area.

4.g. Connect the work cable to the work as close to the welding area as practical. Work cables connected to the building framework or other locations away from the welding area increase the possibility of the welding current passing through lifting chains, crane cables or other alternate cir- cuits. This can create fire hazards or overheat lifting chains or cables until they fail.

4.h. Also see item 7c.

CYLINDER may explode if damaged.

5.a. Use only compressed gas cylinders

containing the correct shielding gas for the process used and properly operating regulators designed for the gas and

pressure used. All hoses, fittings, etc. should be suitable for the application and maintained in good condition.

5.b. Always keep cylinders in an upright position securely chained to an undercarriage or fixed support.

5.c. Cylinders should be located:

Away from areas where they may be struck or subjected to physical damage.

A safe distance from arc welding or cutting operations and any other source of heat, sparks, or flame.

5.d. Never allow the electrode, electrode holder or any other electrically “hot” parts to touch a cylinder.

5.e. Keep your head and face away from the cylinder valve outlet when opening the cylinder valve.

5.f. Valve protection caps should always be in place and hand tight except when the cylinder is in use or connected for use.

5.g. Read and follow the instructions on compressed gas cylinders, associated equipment, and CGA publication P-l, “Precautions for Safe Handling of Compressed Gases in Cylinders,” available from the Compressed Gas Association 1235 Jefferson Davis Highway, Arlington, VA 22202.

FOR ELECTRICALLY powered equipment.

6.a. Turn off input power using the disconnect switch at the fuse box before working on the equipment.

6.b. Install equipment in accordance with the U.S. National Electrical Code, all local codes and the manufacturer’s recommendations.

6.c. Ground the equipment in accordance with the U.S. National Electrical Code and the manufacturer’s recommendations.

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Mar. ‘93

SQUARE WAVE TIG 255

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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 Connections Ground ConnectionInput Supply Connections Reconnect Procedure Output ConnectionsTIG Torch Connection 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 OperationTIG Welding Sequence Operation 2-STEP Mode Table B.2 Typical Current Ranges 1 for Tungsten ElectrodesSquare Wave TIG 255 12/95 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 Problems Symptoms Possible Areas of MisadjustmentsRecommended Course of Action 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 LocationsControl Transformer T2 Voltage Test Test DescriptionMaterials Needed 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 ModeAC TIG Mode Auto Balance on Machine Loaded to 50 Amps AT 26VACMachine Loaded to 200 Amps AT 46 VAC 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 Retest After Repair Input Idle AmpsRecommended Meters for Machine Output Tests 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