Miller Electric Bobcat 250 Owner's Manual
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Miller Electric Bobcat 250 Owner's Manual

Miller bobcat 250 owner's manual
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Bobcat 250
OM-4419
211 392M
2007−05
Processes
Stick (SMAW) Welding
MIG (GMAW) Welding
Flux Cored (FCAW) Welding
Non-Critical TIG (GTAW)
Welding
Description
Engine Driven Welding Generator
File: Engine Drive

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Summary of Contents for Miller Electric Bobcat 250

  • Page 1 Visit our website at www.MillerWelds.com Bobcat 250 OM-4419 211 392M 2007−05 Processes Stick (SMAW) Welding MIG (GMAW) Welding Flux Cored (FCAW) Welding Non-Critical TIG (GTAW) Welding Description Engine Driven Welding Generator File: Engine Drive...
  • Page 2 ISO 9001:2000 Quality System Standard. particular model are also provided. Miller Electric manufactures a full line of welders and welding related equipment. For information on other quality Miller products, contact your local Miller distributor to receive the latest full line catalog or individual specification sheets.

  • Page 3: Table Of Contents

    TABLE OF CONTENTS SECTION 1 − SAFETY PRECAUTIONS − READ BEFORE USING 1-1. Symbol Usage ............... 1-2.
  • Page 4 TABLE OF CONTENTS SECTION 8 − MAINTENANCE (ROBIN-POWERED UNITS) 8-1. Routine Maintenance (Robin-Powered Units) 8-2. Maintenance Label (Robin-Powered Units) 8-3. Servicing Air Cleaner (Robin-Powered Units) 8-4. Overload Protection (Robin-Powered Units) 8-5. Changing Engine Oil, Oil Filter, and Fuel Filter (Robin-Powered Units) 8-6.

  • Page 5: Section 1 − Safety Precautions − Read Before Using

    SECTION 1 − SAFETY PRECAUTIONS − READ BEFORE USING Protect yourself and others from injury — read and follow these precautions. 1-1. Symbol Usage DANGER! − Indicates a hazardous situation which, if not avoided, will result in death or serious injury. The possible hazards are shown in the adjoining symbols or explained in the text.
  • Page 6 FUMES AND GASES can be hazardous. Welding produces fumes and gases. Breathing these fumes and gases can be hazardous to your health. D Keep your head out of the fumes. Do not breathe the fumes. D If inside, ventilate the area and/or use local forced ventilation at the arc to remove welding fumes and gases.

  • Page 7: Engine Hazards

    1-3. Engine Hazards BATTERY EXPLOSION can BLIND. D Always wear a face shield, rubber gloves, and protective clothing when working on a battery. D Stop engine before disconnecting or connect- ing battery cables or servicing battery. D Do not allow tools to cause sparks when working on a battery. D Do not use welder to charge batteries or jump start vehicles.

  • Page 8: Additional Symbols For Installation, Operation, And Maintenance

    HOT METAL from air arc cutting and gouging can cause fire or explosion. D Do not cut or gouge near flammables. D Watch for fire; keep extinguisher nearby. HOT PARTS can cause burns and injury. D Do not touch hot compressor or air system parts.

  • Page 9: California Proposition 65 Warnings

    H.F. RADIATION can cause interference. D High-frequency (H.F.) can interfere with radio navigation, safety services, computers, and communications equipment. D Have only qualified persons familiar with electronic equipment perform this installation. D The user is responsible for having a qualified electrician promptly correct any interference problem resulting from the installation.

  • Page 10: Section 2 − Consignes De Sécurité − Lire Avant Utilisation

    SECTION 2 CONSIGNES DE SÉCURITÉ − LIRE AVANT − Se protéger, ainsi que toute autre personne travaillant sur les lieux, contre les étincelles et le métal chaud. 2-1. Signification des symboles DANGER! − Indique une situation dangereuse qui si on l’évite pas peut donner la mort ou des blessures graves.
  • Page 11 Une tension DC importante subsiste à l’intérieur des onduleurs après avoir coupé l’alimentation. D Couper l’alimentation du poste et décharger les condensateurs d’entrée comme indiqué dans la Section Maintenance avant de toucher des composants. DES PIÈCES CHAUDES peuvent provoquer des brûlures graves. D Ne pas toucher à...

  • Page 12: Dangers Existant En Relation Avec Le Moteur

    D Suivre les recommandations dans OSHA 1910.252(a)(2)(iv) et NFPA 51B pour les travaux à chaud et avoir de la surveillance et un extincteur à proximité. LE BRUIT peut affecter l’ouïe. Le bruit des processus et des équipements peut affec l’ouïe. D Porter des protections approuvés pour les ore les si le niveau sonore est trop élevé.

  • Page 13: Dangers Liés À L'air Comprimé

    D Dévisser le bouchon légèrement et laisser la vapeur s’échapper avant d’enlever le bouchon. L’utilisation d’un groupe autonome à l’intérieur PEUT VOUS TUER EN QUELQUES MINUTES. D Les fumées d’un groupe autonome contient du monoxyde de carbone. C’est un poison invisi- ble et inodore.
  • Page 14 LE SURCHAUFFEMENT peut endom- mager le moteur électrique. D Arrêter ou déconnecter l’équipement avant de démarrer ou d’arrêter le moteur. D Ne pas laisser tourner le moteur trop lentement sous risque d’en- dommager le moteur électrique à cause d’une tension et d’une fré- quence trop faibles.

  • Page 15: Proposition Californienne 65 Avertissements

    2-6. Proposition californienne 65 Avertissements Les équipements de soudage et de coupage produisent des fumées et des gaz qui contiennent des produits chimiques dont l’État de Californie reconnaît qu’ils provoquent des mal- formations congénitales et, dans certains cas, des cancers. (Code de santé...

  • Page 16: Section 3 − Definitions

    SECTION 3 − DEFINITIONS 3-1. Symbol Definitions Stop Engine Start Engine Engine Oil Engine Choke Positive Welding Arc (Electrode) Hours Circuit Protector SECTION 4 − SPECIFICATIONS 4-1. Weld, Power, and Engine Specifications This unit uses either a Robin EH-65 or a Kohler CH-23 engine. Differences between models are noted throughout this manual. Rated Welding Weld Output...

  • Page 17: Dimensions, Weights, And Operating Angles

    4-2. Dimensions, Weights, and Operating Angles Dimensions 33-1/2 in (851 mm) Height (To Top Of Exhaust) Width 20 in (508 mm) Depth 45-3/8 in (1153 mm) 20 in (508 mm) 16-1/2 in (419 mm) 1-3/4 in (44 mm) 6-1/16 in (154 mm) 32-3/4 in (832 mm) 45-3/8 in (1153 mm) 13/32 in (10 mm) Dia.

  • Page 18: Fuel Consumption (Robin-Powered Units)

    4-4. Fuel Consumption (Robin-Powered Units) 4-5. Fuel Consumption (Kohler-Powered Units) OM-4419 Page 14 A complete Parts List is available at www.MillerWelds.com On a typical job using 1/8 in 7018 electrodes (125 amps, 20% duty cycle), expect about 20 hours of op- eration.

  • Page 19: Volt-Ampere Curves

    4-6. Volt-Ampere Curves A. For CC/AC Mode B. For CC/DC Mode C. For CV/DC Mode A complete Parts List is available at www.MillerWelds.com The volt-ampere curve shows the minimum and maximum voltage and amperage output capabilities of the welding generator. Curves of all other settings fall between the curves shown.

  • Page 20: Generator Power Curve

    4-7. Generator Power Curve 4-8. Duty Cycle OM-4419 Page 16 A complete Parts List is available at www.MillerWelds.com Continuous Welding 100% Duty Cycle at 250 Amperes The generator power curve shows the generator power in amperes available at the receptacles. 200 294 Duty cycle is the percentage of 10 minutes that unit can weld at rated...

  • Page 21: Section 5 − Installation

    SECTION 5 − INSTALLATION 5-1. Installing Welding Generator Movement Do not lift unit from end. Location / Airflow Clearance 18 in (460 mm) 18 in (460 mm) 18 in 18 in (460 mm) (460 mm) Mounting Inadequate support. Do not use flexible mounts. Grounding Bed liners, shipping skids, and some running gears in- sulate the welding generator from the vehicle frame.

  • Page 22: Engine Prestart Checks (Robin-Powered Units)

    5-2. Engine Prestart Checks (Robin-Powered Units) Full Full Gasoline OM-4419 Page 18 A complete Parts List is available at www.MillerWelds.com Oil Fill Oil Check 0000 Check all fluids daily. Engine must be cold and on a level surface. Unit is shipped with 10W30 engine oil. Follow run-in procedure in en- gine manual.

  • Page 23: Engine Prestart Checks (Kohler-Powered Units)

    5-3. Engine Prestart Checks (Kohler-Powered Units) Full Gasoline A complete Parts List is available at www.MillerWelds.com Full 0000 Check all fluids daily. Engine must be cold and on a level surface. Unit is shipped with 10W30 engine oil. Follow run-in procedure in en- gine manual.

  • Page 24: Installing Exhaust Pipe

    5-4. Installing Exhaust Pipe 5-5. Connecting Or Replacing the Battery Connecting The Battery Replacing The Battery Tools Needed: 3/8, 1/2 in OM-4419 Page 20 A complete Parts List is available at www.MillerWelds.com Engine backfire can cause se- vere burns or other injuries. Do not point exhaust pipe to- ward control panel.

  • Page 25: Connecting To Weld Output Terminals

    5-6. Connecting to Weld Output Terminals Do not place anything between weld cable terminal and copper bar. Correct Installation A complete Parts List is available at www.MillerWelds.com Incorrect Installation Stop engine. Work Weld Output Terminal Electrode Weld Output Terminal Connect work cable to Work terminal. Connect electrode holder cable or electrode weld cable to Electrode ter- minal for Stick and MIG welding.

  • Page 26: Selecting Weld Cable Sizes

    5-7. Selecting Weld Cable Sizes* Weld Output Terminals Turn off power before connecting to weld output terminals. Do not use worn, damaged, under- sized, poorly spliced cables. Welding Amperes This chart is a general guideline and may not suit all applications. If cables overheat, use next size larger cable. **Weld cable size (AWG) is based on either a 4 volts or less drop or a current density of at least 300 circular mils per ampere.

  • Page 27: Section 6 − Operating The Welding Generator

    SECTION 6 − OPERATING THE WELDING GENERATOR 6-1. Front Panel Controls Engine Control Switch Use switch to start engine, select speed, and stop engine. In Run/Idle position, engine runs at idle speed at no load, and weld/power speed under load. In Run position, engine runs at weld/power speed.

  • Page 28: Cold Weather Engine Operation

    6-2. Cold Weather Engine Operation Infrequently Loaded Frequently Loaded Ref. 228 201-B Notes OM-4419 Page 24 A complete Parts List is available at www.MillerWelds.com Engine Control Switch Carburetor Icing Carburetor icing causes the unit to drop below the normal idle speed and then stall.

  • Page 29: Typical Stick Welding Connections And Control Settings

    6-3. Typical Stick Welding Connections And Control Settings Typical Settings For 7018 (1/8 in) Electrode Electrode Selection Table (Beneath Cover) 3/32 6010 5/32 & 3/16 6011 7/32 1/16 5/64 3/32 6013 5/32 3/16 7/32 3/32 5/32 7014 3/16 7/32 3/32 5/32 7018 3/16...

  • Page 30: Typical Mig Welding Connections And Settings

    6-4. Typical MIG Welding Connections And Settings A. Solid Wire Applications Typical Control Settings For .035 (ER70S-3) Note Coarse Range, Fine Control, and Weld Process switch settings. Tools Needed: 3/4 in OM-4419 Page 26 A complete Parts List is available at www.MillerWelds.com Solid Wire −...
  • Page 31 B. Self-Shielded Flux Core Wire Applications Typical Control Settings For .045 (71T-11) Self-Shielded Flux Core Wire Note Coarse Range, Fine Control, and Weld Process switch settings. Tools Needed: 3/4 in A complete Parts List is available at www.MillerWelds.com Quick connector Work Stop engine.

  • Page 32: Typical Mig Connections And Settings Using Weld Control And Spoolgun

    6-5. Typical MIG Connections And Settings Using Weld Control And Spoolgun Tools Needed: 3/4 in Work This section provides general guide- lines and may not suit all applications. Weld Control Spoolgun Optional Contactor (Recommended) Reed Switch Weld Cable (Customer-Supplied) Weld Control Weld Terminal Weld Power Cable From Spoolgun Work Clamp Gas Hose...

  • Page 33: Section 7 − Operating Auxiliary Equipment

    SECTION 7 − OPERATING AUXILIARY EQUIPMENT 7-1. Generator Power Receptacles A complete Parts List is available at www.MillerWelds.com If unit does not have GFCI recep- tacles, use GFCI-protected extension cord. Generator power decreases as weld current increases. Set Fine Control R1 at 10 for full genera- tor power.

  • Page 34: Simultaneous Weld And Power

    7-2. Simultaneous Weld And Power Weld Current in Amperes Total Power in Watts 7-3. Wiring Optional 240 Volt Plug Current Available in Amperes 240 V Each 120 V Duplex Receptacle* Receptacle V x A = Watts *One 240 V load or two 120 V loads. OM-4419 Page 30 A complete Parts List is available at www.MillerWelds.com 120 V Full kVA Receptacle...

  • Page 35: Section 8 − Maintenance (Robin-Powered Units)

    SECTION 8 − MAINTENANCE (ROBIN-POWERED UNITS) 8-1. Routine Maintenance (Robin-Powered Units) n = Check Z = Change * To be done by Factory Authorized Service Agent Every Hours n Fuel Level n Oil Level Every Hours n~ Spark Arrestor Screen Every Hours ~ Air Cleaner Wrapper...

  • Page 36: Maintenance Label (Robin-Powered Units)

    A complete Parts List is available at www.MillerWelds.com 8-2. Maintenance Label (Robin-Powered Units) OM-4419 Page 32...

  • Page 37: Servicing Air Cleaner (Robin-Powered Units)

    8-3. Servicing Air Cleaner (Robin-Powered Units) 8-4. Overload Protection (Robin-Powered Units) Fuses F1, F2 located on bracket behind left side panel. Tools Needed: 3/8 in A complete Parts List is available at www.MillerWelds.com Fuse F6 located in harness behind left side door.

  • Page 38: Changing Engine Oil, Oil Filter, And Fuel Filter (Robin-Powered Units)

    8-5. Changing Engine Oil, Oil Filter, and Fuel Filter (Robin-Powered Units) Oil Check Full Tools Needed: OM-4419 Page 34 A complete Parts List is available at www.MillerWelds.com Oil Fill Stop engine and let cool. Oil Drain Valve 1/2 ID x 7 in Hose Oil Filter Change engine oil and filter accord- ing to engine owner’s manual.

  • Page 39: Adjusting Engine Speed (Robin-Powered Units)

    8-6. Adjusting Engine Speed (Robin-Powered Units) A complete Parts List is available at www.MillerWelds.com 2200 − 2300 rpm (36.6 − 38.3 Hz) 3675 − 3750 rpm (61.3 − 62.5 Hz) After tuning engine, check engine speeds with a tachometer (see table).

  • Page 40: Servicing Optional Spark Arrestor (Robin-Powered Units)

    8-7. Servicing Optional Spark Arrestor (Robin-Powered Units) Tools Needed: 1/4 in Notes OM-4419 Page 36 A complete Parts List is available at www.MillerWelds.com Stop engine and let cool. Spark Arrestor Screen Clean and inspect screen. Replace spark arrestor if screen wires are broken or missing.

  • Page 41: Section 9 − Maintenance − (Kohler-Powered Units)

    SECTION 9 − MAINTENANCE − (KOHLER-POWERED UNITS) 9-1. Routine Maintenance (Kohler-Powered Units) n = Check Z = Change * To be done by Factory Authorized Service Agent Every Hours n Fuel Level n Oil Level Every Hours n~ Spark Arrestor Screen Every Hours ~ Air Cleaner Wrapper...

  • Page 42: Maintenance Label (Kohler-Powered Units)

    A complete Parts List is available at www.MillerWelds.com 9-2. Maintenance Label (Kohler-Powered Units) OM-4419 Page 38...

  • Page 43: Servicing Air Cleaner (Kohler−Powered Units)

    9-3. Servicing Air Cleaner (Kohler−Powered Units) Notes A complete Parts List is available at www.MillerWelds.com Stop engine. NOTICE − Do not run engine with- out air cleaner or with dirty element. Precleaner Wash precleaner with soap and wa- ter solution. Allow precleaner to air dry completely.

  • Page 44: Changing Engine Oil, Oil Filter, And Fuel Filter (Kohler-Powered Units)

    9-4. Changing Engine Oil, Oil Filter, and Fuel Filter (Kohler-Powered Units) Full Tools Needed: OM-4419 Page 40 A complete Parts List is available at www.MillerWelds.com Stop engine and let cool. Oil Drain Valve 1/2 ID x 7 in Hose Oil Filter Change engine oil and filter accord- ing to engine owner’s manual.

  • Page 45: Adjusting Engine Speed (Kohler-Powered Units)

    9-5. Adjusting Engine Speed (Kohler-Powered Units) A complete Parts List is available at www.MillerWelds.com 2200 − 2300 rpm (36.6 − 38.3 Hz) 3675 − 3750 rpm (61.3 − 62.5 Hz) Top View After tuning engine, check engine speeds with a tachometer (see table).

  • Page 46: Overload Protection (Kohler-Powered Units)

    9-6. Overload Protection (Kohler-Powered Units) Fuses F1, F2 located on bracket behind left side panel. 9-7. Servicing Optional Spark Arrestor (Kohler-Powered Units) Tools Needed: 1/4 in OM-4419 Page 42 A complete Parts List is available at www.MillerWelds.com Fuse F6 located in harness behind left side door.

  • Page 47: Section 10 − Troubleshooting

    SECTION 10 − TROUBLESHOOTING 10-1. Welding Troubleshooting Trouble Low or no weld output; generator pow- Check control settings. er output okay at ac receptacles. Check weld connections. Check fuse F1, and replace if open (see Section 8-4 or 9-6). Have Factory Authorized Service Agent check brushes, slip rings, and integrated rectifiers SR2 and SR3.

  • Page 48: Engine Troubleshooting

    Trouble Low power output at ac receptacles. Check fuse F2, and replace if open (see Section 8-4 or 9-6). Increase Fine control R1 setting to max. High power output at ac receptacles. Check engine speed, and adjust if necessary (see Section 8-6 or 9-5). Erratic power output at ac receptacles.

  • Page 49: Section 11 − Parts List

    Trouble Unstable or sluggish engine speeds. Readjust throttle linkage if necessary. Check throttle solenoid TS1 for smooth operation. Check oil level. Oil level should not exceed Full mark on dipstick. Fuel pump will operate erratically if crankcase is overfilled. Tune-up engine according to engine manual. Engine does not return to idle speed.

  • Page 50: Section 12 − Electrical Diagrams

    SECTION 12 − ELECTRICAL DIAGRAMS Figure 12-1. Circuit Diagram For Welding Generator OM-4419 Page 46...
  • Page 51 228 460-A OM-4419 Page 47...

  • Page 52: Section 13 − Generator Power Guidelines

    SECTION 13 − GENERATOR POWER GUIDELINES The views in this section are intended to be representative of all engine-driven welding generators. Your unit may differ from those shown. 13-1. Selecting Equipment 13-2. Grounding Generator To Truck Or Trailer Frame GND/PE OM-4419 Page 48 Generator Power Receptacles −...

  • Page 53: Grounding When Supplying Building Systems

    13-3. Grounding When Supplying Building Systems 13-4. How Much Power Does Equipment Require? GND/PE VOLTS 115 AMPS Equipment Grounding Terminal Grounding Cable Use #10 AWG or larger insulated copper wire. Ground Device Use ground device as stated in electrical codes. Ground generator to system earth ground if supplying power to a premises (home,...
  • Page 54 13-5. Approximate Power Requirements For Industrial Motors Industrial Motors Split Phase Capacitor Start-Induction Run Capacitor Start-Capacitor Run Fan Duty 13-6. Approximate Power Requirements For Farm/Home Equipment Farm/Home Equipment Stock Tank De-Icer Grain Cleaner Portable Conveyor Grain Elevator Milk Cooler Milker (Vacuum Pump) FARM DUTY MOTORS Std.
  • Page 55 13-7. Approximate Power Requirements For Contractor Equipment Contractor Hand Drill Circular Saw Table Saw Band Saw Bench Grinder Air Compressor Electric Chain Saw Electric Trimmer Electric Cultivator Elec. Hedge Trimmer Flood Lights Submersible Pump Centrifugal Pump Floor Polisher High Pressure Washer 55 gal Drum Mixer Wet &...
  • Page 56 13-8. Power Required To Start Motor Motor Start Code KVA/HP 13-9. How Much Power Can Generator Supply? OM-4419 Page 52 Single-Phase Induction Motor Starting Requirements 10.0 AC MOTOR VOLTS AMPS CODE PHASE 11.2 12.5 Motor Start Code Running Amperage Motor HP Motor Voltage To find starting amperage: Step 1: Find code and use table to...
  • Page 57 13-10. Typical Connections To Supply Standby Power Utility Electrical Transfer Switch Service Essential Loads Fused Welding Disconnect Generator Switch Output (If Required) Have only qualified persons perform these connections according to all applicable codes and safety practices. Properly install and ground this equipment according to its Owner’s Manual and na- tional, state, and local codes.
  • Page 58 13-11. Selecting Extension Cord (Use Shortest Cord Possible) Cord Lengths for 120 Volt Loads If unit does not have GFCI receptacles, use GFCI-protected extension cord. Current Load (Watts) (Amperes) 1200 1800 2400 3000 3600 4200 4800 5400 6000 *Conductor size is based on maximum 2% voltage drop Cord Lengths for 240 Volt Loads If unit does not have GFCI receptacles, use GFCI-protected extension cord.

  • Page 59: Section 14 − Stick Welding (Smaw) Guidelines

    SECTION 14 − STICK WELDING (SMAW) GUIDELINES 14-1. Stick Welding Procedure Tools Needed: Weld current starts when electrode touches work- piece. Weld current can damage electronic parts in vehicles. Disconnect both battery cables before welding on a vehicle. Place work clamp as close to the weld as possible.

  • Page 60: Electrode And Amperage Selection Chart

    14-2. Electrode and Amperage Selection Chart 3/32 6010 5/32 & 3/16 6011 7/32 1/16 5/64 3/32 6013 5/32 3/16 7/32 3/32 5/32 7014 3/16 7/32 3/32 5/32 7018 3/16 7/32 3/32 5/32 7024 3/16 7/32 3/32 Ni-Cl 5/32 3/16 3/32 308L 5/32 14-3.
  • Page 61 14-5. Positioning Electrode Holder End View of Work Angle End View of Work Angle 14-6. Poor Weld Bead Characteristics 14-7. Good Weld Bead Characteristics 10 -30 Side View of Electrode Angle GROOVE WELDS 10 -30 Side View of Electrode Angle FILLET WELDS S-0060 Large Spatter Deposits...

  • Page 62: Conditions That Affect Weld Bead Shape

    14-8. Conditions That Affect Weld Bead Shape Weld bead shape is affected by electrode angle, arc length, travel speed, and thickness of base metal. Angle Too Small Too Short Slow 14-9. Electrode Movement During Welding Normally, a single stringer bead is satisfactory for most narrow groove weld joints; however, for wide groove weld joints or bridging across gaps, a weave bead or multiple stringer beads work better.

  • Page 63: Butt Joints

    14-10. Butt Joints 14-11. Lap Joint Or Less Single-Layer Fillet Weld 14-12. Tee Joint 1/16 in (1.6 mm) Or Less Multi-Layer Fillet Weld Less Tack Welds Prevent edges of joint from draw- ing together ahead of electrode by tack welding the materials in posi- tion before final weld.

  • Page 64: Weld Test

    14-13. Weld Test 2 To 3 in (51-76 mm) 1/4 in (6.4 mm) 14-14. Troubleshooting − Porosity Possible Causes Arc length too long. Damp electrode. Workpiece dirty. 14-15. Troubleshooting − Excessive Spatter Possible Causes Amperage too high for electrode. Arc length too long or voltage too high. OM-4419 Page 60 2 To 3 in (51-76 mm)
  • Page 65 14-16. Troubleshooting − Incomplete Fusion Possible Causes Insufficient heat input. Improper welding technique. Workpiece dirty. 14-17. Troubleshooting − Lack Of Penetration Lack of Penetration Good Penetration Possible Causes Improper joint preparation. Improper weld technique. Insufficient heat input. 14-18. Troubleshooting − Excessive Penetration Excessive Penetration Good Penetration Possible Causes...
  • Page 66 14-19. Troubleshooting − Burn-Through Possible Causes Excessive heat input. 14-20. Troubleshooting − Waviness Of Bead Possible Causes Unsteady hand. Use two hands. Practice technique. 14-21. Troubleshooting − Distortion Base metal moves in the direction of the weld bead. Possible Causes Excessive heat input.

  • Page 67: Section 15 − Mig Welding (Gmaw) Guidelines

    SECTION 15 − MIG WELDING (GMAW) GUIDELINES 15-1. Typical MIG Process Connections Using A Voltage-Sensing Wire Feeder Workpiece Work Clamp Voltage Sensing Clamp 15-2. Holding And Positioning Welding Gun Welding wire is energized when gun trigger is pressed. Before lowering helmet and pressing trigger, be sure wire is no more than 1/2 in (13 mm) past end of nozzle, and tip of wire is positioned correctly on seam.

  • Page 68: Conditions That Affect Weld Bead Shape

    15-3. Conditions That Affect Weld Bead Shape Weld bead shape depends on gun angle, direction of travel, electrode extension (stickout), travel speed, thickness of base metal, wire feed speed (weld current), and voltage. Short Short FILLET WELD ELECTRODE EXTENSIONS (STICKOUT) Slow OM-4419 Page 64 Push...

  • Page 69: Gun Movement During Welding

    15-4. Gun Movement During Welding Normally, a single stringer bead is satisfactory for most narrow groove weld joints; however, for wide groove weld joints or bridging across gaps, a weave bead or multiple stringer beads works better. 15-5. Poor Weld Bead Characteristics 15-6.

  • Page 70: Troubleshooting − Excessive Spatter

    15-7. Troubleshooting − Excessive Spatter Possible Causes Wire feed speed too high. Voltage too high. Electrode extension (stickout) too long. Workpiece dirty. Insufficient shielding gas at welding arc. Dirty welding wire. 15-8. Troubleshooting − Porosity Possible Causes Insufficient shielding gas at welding arc. Wrong gas.

  • Page 71: Troubleshooting − Lack Of Penetration

    15-10. Troubleshooting − Lack Of Penetration Lack of Penetration Good Penetration Possible Causes Improper joint preparation. Improper weld technique. Insufficient heat input. 15-11. Troubleshooting − Incomplete Fusion Possible Causes Workpiece dirty. Insufficient heat input. Improper welding technique. 15-12. Troubleshooting − Burn-Through Possible Causes Excessive heat input.

  • Page 72: Troubleshooting − Waviness Of Bead

    15-13. Troubleshooting − Waviness Of Bead Possible Causes Welding wire extends too far out of nozzle. Unsteady hand. 15-14. Troubleshooting − Distortion Base metal moves in the direction of the weld bead. Possible Causes Excessive heat input. OM-4419 Page 68 Waviness Of Bead −...

  • Page 73: Common Mig Shielding Gases

    15-15. Common MIG Shielding Gases This is a general chart for common gases and where they are used. Many different combinations (mixtures) of shielding gases have been developed over the years. The most commonly used shielding gases are listed in the following table.
  • Page 75 Warranty Questions? LIMITED WARRANTY − Subject to the terms and conditions Call below, Miller Electric Mfg. Co., Appleton, Wisconsin, warrants to 1-800-4-A-MILLER its original retail purchaser that new Miller equipment sold after the effective date of this limited warranty is free of defects in for your local material and workmanship at the time it is shipped by Miller.
  • Page 76 File a claim for loss or damage during shipment. For assistance in filing or settling claims, contact your distributor and/or equipment manufacturer’s Transportation Department. 2007 Miller Electric Mfg. Co. 2007−01 Miller Electric Mfg. Co. An Illinois Tool Works Company 1635 West Spencer Street Appleton, WI 54914 USA International Headquarters−USA...

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