Lincoln Electric SVM208-A service manual Vertical-Up Welding, Vertical-Down Welding

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B-14

OPERATION

B-14

 

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Vertical-Up Welding

The problem, when welding vertical-up, is to put the molten metal where it is wanted and make it stay there. If too much molten metal is deposited, gravity will pull it downwards and make it “drip”. Therefore, a certain technique has to be followed:

Long arc

Short arc

NOTE: Holder end of electrode is lower than arc.

1.Use 1/8” (3.2mm) 90-115 amps or 3/32” (2.5mm) 70 amps AWS 6011.

2.When welding, the electrode should be kept hori- zontal or pointing slightly upwards. (See drawing above).

3.The arc is struck and metal deposited at the bottom of the two pieces to be welded together.

4.Before too much molten metal is deposited, the arc is SLOWLY moved 1/2-3/4” (12-20mm) upwards. This takes the heat away from the molten puddle, which solidifies. (If the arc is not taken away soon enough, too much metal will be deposited, and it will “drip”.)

5.The upward motion of the arc is caused by a very slight wrist motion. Most definitely, the arm must not move in and out, as this makes the entire process very complicated and difficult to learn.

6.If the upward motion of the arc is done correctly with a wrist motion, the arc will automatically become a long arc that deposits little or no metal. (See drawing above.)

7.During this entire process, the ONLY thing to watch is the molten metal. As soon as it has solidified, the arc is SLOWLY brought back, and another few drops of metal are deposited. DO NOT  FOLLOW

THE UP AND DOWN MOVEMENT OF THE ARC WITH YOUR EYES. KEEP THEM ON THE MOLTEN METAL.

8.When the arc is brought back to the now solidified puddle, IT MUST BE SHORT, otherwise no metal will be deposited, the puddle will melt again, and it will “drip”.

9.It is important to realize that the process consists of SLOW, DELIBERATE movements. There are no fast motions.

Vertical-Down Welding

Vertical-down welds are applied at a fast pace. These welds are therefore shallow and narrow, and are excel- lent for sheet metal. Do not use the vertical-down tech- nique on heavy metal. The welds will not be strong enough.

1.Use 1/8” (3.2m) or 3/32” (2.5mm) AWS 6011.

2.On thin metal use 70-75 amps.

(14 ga. 75 A - 16 ga. 60 A.)

3.Hold the electrode in a 30-45° angle with the tip of the electrode pointing upwards.

4.Hold a VERY SHORT arc, but do not let the elec- trode touch the metal.

 

Very

5. An up and down whipping

short

motion will help prevent

arc

burn-through on very thin plate.

30°-40°

 

6. Watch the molten metal carefully.

The important thing is to continue lowering the entire arm as the weld is made so the angle of the electrode does not change. Move the electrode fast enough so that the slag does not catch up with the arc.

BULLDOG® 140

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Contents Bulldog Safety California Proposition 65 WarningsElectric Shock can kill ARC Rays can burn Can be dangerousWelding and Cutting Sparks can cause fire or explosion Cylinder may explode if damagedIii Précautions 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 Technical Specifications Bulldog 140 K2708-1Storing Safety PrecautionsLocation and Ventilation Engine Exhaust can killTilting PRE-OPERATION Engine ServiceStacking OILElectrical Output CONNEC- Tions Welding Cable ConnectionsTable A.1 Recommended Welding Cable Size and Length Electrical Connections Auxiliary Power ReceptaclesCable Installation Plugs and HAND-HELD EquipmentPremises Wiring Circuit BreakersAtion. do not RUN These BulldogTable of Contents Operation Section Operation Limitations WELDER/GENERATOR ControlsOutput Panel Controls Engine Operation Gasoline Engine ControlsBefore Starting the Engine Starting the EngineGenerator Operation Table B.1 Generator Power Applications Welding Operation Control Function / OperationStick Welding Material Thickness Electrode Type Size SettingWelding Guidelines Learning To Stick WeldWhat Happens in the Arc? Correct Welding Position Side viewDo the following PracticeUse the following Butt JointsFillet Joints PenetrationVertical-Up Welding Vertical-Down WeldingWelding Sheet Metal How to Hardface the Sharp Edge Metal to Ground WearOverhead Welding Hardfacing To Reduce WearWelding Cast Iron Cast Iron Plate PreparationHigh-Speed Group AWS E6013 Low Hydrogen Group AWS E7018Out-of-Position Group AWS E6011 Bulldog Table of Contents Accessories Section Accessories OPTIONS/ACCESSORIESLincoln Electric Accessories Table of Contents Maintenance Section Maintenance Routine and Periodic Maintenance Engine MaintenanceLocation Engine Adjustments Return to Section TOC To Section TOCTable D.1 Engine Maintenance Parts Spark Plug ServiceOperational Clearance GENERATOR/WELDER Maintenance Screws BrushesFigure D.7. Major Component Locations Bulldog 1TABLE of CONTENTS-THEORY of Operation Section E-1 Theory of Operation ENGINE, EXCITATION, Rotor StatorRotor Field Feedback Auxiliary Power Figure E.3 Rotor Field Feedback and Auxiliary PowerAuxiliary Power Overcurrent Protection Weld Winding and Reactor1TABLE of Contents Troubleshooting and Repair F-1 Troubleshooting and Repair HOW to USE Troubleshooting GuidePC Board Troubleshooting Procedures Output Problems Electric Authorized Field Ser vice Facility Perform the Rotor Voltage TestProblems Symptoms Troubleshooting and Repair Perform Field Diode Test Engine Problems Troubleshooting and Repair Engine Throttle Adjustment Test Bulldog Rotor Voltage Test Test DescriptionMaterials Needed Procedure Rotor Voltage TestLead 200A Connection Ground Stud Field Diode Bridge Test Field Diode Bridge Test + ~Rotor Flashing Circuit Test Rotor Flashing Circuit Test Figure F.3 Brush Holder Leads 201- and 202B +Moving Parts can injure Bulldog Rotor Resistance Test Rotor Resistance Test Cable TIE Brushes Figure F.6 Brushes Retained with Cable TIEBulldog Engine Throttle Adjustment Test ROBIN/SUBARU Engine Strobe-tach Method Engine Throttle Adjustment TestROBIN/SUBARU Engine Frequency Counter MethodHigh Speed Stop Screw Scope Settings Normal Open Circuit Voltage Waveform 115VAC Supply High Idle no LoadTypical Weld Output Waveform Machine LoadedMachine Loaded to 125 Amps AT 23 VAC Brush Removal and Replacement Brush Removal and Replacement Cable TIE BrushesReturn to Section Return to Section TOC Bulldog Rheostat Removal and Replacement Rheostat Removal and Replacement Figure F.11 Rheostat RemovalCapacitor AND/OR Diode Bridge Removal and Replacement Removal and Replacement Procedure Capacitor Removal and ReplacementCapacitor AND/OR Diode Bridge Procedure Field Diode Bridge Removal and Replacement Figure F.13 Field Diode Bridge LocationBulldog STATOR/ROTOR Removal and Replacement InstructionsSTATOR/ROTOR Removal and Replacement GeneratorengineFigure F.15 Generator Components Troubleshooting and Repair Stator Removal Procedure Figure F.16 Output Lead Location TIE Wrap TerminalsThru Bolts Support NutsRotor Removal Procedure Reassembly ProcedureFigure F.19 Checking ROTOR-STATOR AIR GAP Engine Output Auxiliary Power Receptacle OUTPUT1Retest After Repair WELDER/GENERATOR OUTPUT1Bulldog Table of Contents Diagram Section Wiring Diagram Bulldog S28101