Miller Millermatic 251 Owner's Manual
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Miller Millermatic 251 Owner's Manual

Miller Millermatic 251 Owner's Manual

Arc welding power source and wire feeder
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Millermatic 251
OM-1326
205 654Z
2007−02
Processes
MIG (GMAW) Welding
Flux Cored (FCAW) Welding
Description
Arc Welding Power Source
and Wire Feeder
R
File: MIG (GMAW)

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Summary of Contents for Miller Millermatic 251

  • Page 1 OM-1326 205 654Z 2007−02 Processes MIG (GMAW) Welding Flux Cored (FCAW) Welding Description Arc Welding Power Source and Wire Feeder Millermatic 251 Visit our website at File: MIG (GMAW) www.MillerWelds.com...
  • 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.
  • Page 4 TABLE OF CONTENTS SECTION 8 − MIG WELDING (GMAW) GUIDELINES ..........8-1.

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

    SECTION 1 − SAFETY PRECAUTIONS - READ BEFORE USING som _3/05 Y Warning: Protect yourself and others from injury — read and follow these precautions. 1-1. Symbol Usage Means Warning! Watch Out! There are possible hazards with this procedure! The possible hazards are shown in the adjoining symbols.
  • Page 6 ARC RAYS can burn eyes and skin. BUILDUP OF GAS can injure or kill. D Shut off shielding gas supply when not in use. Arc rays from the welding process produce intense visible and invisible (ultraviolet and infrared) rays D Always ventilate confined spaces or use that can burn eyes and skin.

  • Page 7: Additional Symbols For Installation, Operation, And Maintenance

    1-3. Additional Symbols For Installation, Operation, And Maintenance FIRE OR EXPLOSION hazard. MOVING PARTS can cause injury. D Do not install or place unit on, over, or near D Keep away from moving parts such as fans. combustible surfaces. D Keep all doors, panels, covers, and guards D Do not install unit near flammables.

  • Page 8: Principal Safety Standards

    1-5. Principal Safety Standards Safety in Welding, Cutting, and Allied Processes, ANSI Standard Z49.1, Boulevard, Rexdale, Ontario, Canada (phone: from Global Engineering Documents (phone: 1-877-413-5184, website: 800−463−6727 or in Toronto 416−747−4044, website: www.csa−in- www.global.ihs.com). ternational.org). Practice For Occupational And Educational Eye And Face Protection, Recommended Safe Practices for the Preparation for Welding and Cut- ANSI Standard Z87.1, from American National Standards Institute, 11 ting of Containers and Piping, American Welding Society Standard...

  • Page 9: Section 2 − Consignes De Sécurité − Lire Avant Utilisation

    SECTION 2 − CONSIGNES DE SÉCURITÉ − LIRE AVANT UTILISATION fre_som _3/05 Y Avertissement : se protéger et protéger les autres contre le risque de blessure — lire et respecter ces consignes. 2-1. Symboles utilisés Symbole graphique d’avertissement ! Attention ! Cette pro- cédure comporte des risques possibles ! Les dangers éven- tuels sont représentés par les symboles graphiques joints.
  • Page 10 LES RAYONS D’ARC peuvent entraî- ACCUMULATIONS ner des brûlures aux yeux et à la peau. risquent de provoquer des blessures ou même la mort. Le rayonnement de l’arc du procédé de soudage génère des rayons visibles et invisibles intenses D Fermer l’alimentation du gaz protecteur en cas (ultraviolets et infrarouges) susceptibles de provo- de non-utilisation.

  • Page 11: Dangers Supplémentaires En Relation Avec L'installation, Le Fonctionnement Et La Maintenance

    2-3. Dangers supplémentaires en relation avec l’installation, le fonctionnement et la maintenance Risque D’INCENDIE OU D’EXPLO- DES ORGANES MOBILES peuvent SION. provoquer des blessures. D Ne pas placer l’appareil sur, au-dessus ou D S’abstenir de toucher des organes mobiles tels à...

  • Page 12: Principales Normes De Sécurité

    2-5. Principales normes de sécurité Safety in Welding, Cutting, and Allied Processes, ANSI Standard Z49.1, Boulevard, Rexdale, Ontario, Canada M9W 1R3 (téléphone : de Global Engineering Documents (téléphone : 1-877-413-5184, site In- 800-463-6727 ou à Toronto 416-747-4044, site Internet ternet : www.global.ihs.com). www.csa-international.org).

  • Page 13: Section 3 − Definitions

    SECTION 3 − DEFINITIONS 3-1. Symbols And Definitions Do Not Switch Wire Feed Output Duty Cycle While Welding Volts Increase Gas Metal Arc Wire Feed Spool Welding (GMAW) Gas Input Gas Output Rated No-Load Voltage Input Press To Reset Voltage (Average) SECTION 4 −...

  • Page 14: Welding Power Source Duty Cycle And Overheating

    4-2. Welding Power Source Duty Cycle And Overheating Duty Cycle is percentage of 10 minutes that unit can weld at rated load without overheating. If unit overheats, Thermistor (T) opens, output stops, and cooling fan runs. Wait fifteen minutes for unit to cool.

  • Page 15: Connecting To Weld Output Terminals

    4-4. Connecting To Weld Output Terminals Do not place anything between weld cable terminal and copper bar. Tools Needed: 3/4 in (19 mm) 803 778-A Correct Installation Incorrect Installation Y Turn off power before connecting to Weld Output Terminal minal. Slide weld cable terminal onto weld weld output terminals.

  • Page 16: Connecting Spoolmatic) 15A Or 30A Gun

    4-6. Connecting Spoolmatic) 15A Or 30A Gun Gun Trigger Plug Insert plug into receptacle, and tighten threaded collar. Weld Cable Shielding Gas Hose Route weld cable through opening in front panel. Route gas hose along side panel. Positive Weld Output Terminal Connect weld cable to weld output terminal.

  • Page 17: Setting Gun Polarity For Wire Type

    4-7. Setting Gun Polarity For Wire Type Changing Polarity Polarity Changeover Label Information Always read and follow manufacture’s recommended polarity. Wire Drive Work Clamp Lead Assembly Lead Positive Terminal Negative Terminal Shown as shipped − Electrode Positive (DCEP): For solid steel, stainless steel, aluminum, or flux core with gas wires (GMAW).

  • Page 18: Installing Wire Spool And Adjusting Hub Tension

    4-9. Installing Wire Spool And Adjusting Hub Tension Use compression spring When a slight force is needed with 8 in (200 mm) spools. to turn spool, tension is set. Installing 1 Or 2 lb Wire Spool To install either a 1 lb or 2 lb wire spool, follow the procedure as Spindle shown in the illustration.

  • Page 19: Electrical Service Guide

    4-11. Electrical Service Guide Input Voltage Input Amperes At Rated Output Max Recommended Standard Fuse Or Circuit Breaker Rating In Amperes Circuit Breaker , Time-Delay Normal Operating Min Input Conductor Size In AWG Max Recommended Input Conductor Length In Feet (Meters) (29) (39) (47)

  • Page 20: Selecting A Location And Connecting Input Power

    4-12. Selecting A Location And Connecting Input Power =GND/PE Earth Ground 18 in (457 mm) of space for airflow Y Do not move or operate unit where it could tip. 230 VAC, 1 Ref. 802 477-B / 803 766-B Y Installation must meet all National Plug (NEMA Type 6-50P) Disconnect Device Line Terminals and Local Codes −...

  • Page 21: Threading Welding Wire

    4-13. Threading Welding Wire Wire Spool Welding Wire Inlet Wire Guide Pressure Adjustment Knob Drive Roll Outlet Wire Guide Gun Conduit Cable Lay gun cable out straight. Tools Needed: Hold wire tightly to keep it from unraveling. 6 in (150 mm) Open pressure assembly.

  • Page 22: Using Gun/Cable Holder

    4-14. Using Gun/Cable Holder Side Panel Latch Cable Holder Press latch down to release and open door. Holster (2) Wrap cable around cable holder, and place gun nozzle into holster. Ref. 802 726-A OM-1326 Page 18...
  • Page 23 Notes OM-1326 Page 19...

  • Page 24: Weld Parameters

    4-15. Weld Parameters OM-1326 Page 20...
  • Page 25 201 202-A OM-1326 Page 21...

  • Page 26: Section 5 − Operation

    SECTION 5 − OPERATION 5-1. Controls Voltage Control Turn control clockwise to increase voltage. Wire Speed Control Turn control clockwise to increase wire feed speed. JOG Mode If the trigger on either gun is held for more than 3 seconds without striking an arc, the unit will automatically shut off weld power (and shielding gas output on MIG gun only), but will feed...

  • Page 27: Voltmeter And Wire Feed Speed Meter Operation

    5-2. Voltmeter And Wire Feed Speed Meter Operation Voltmeter If welding resumes before unit displays Wire Feed Speed Display (001) preset voltage, actual welding voltage will Wire Feed Speed Meter HL.P 001 − Communication Lost between appear on the voltmeter. Control Board PC1 and Display Board PC2 Power Up Status The wire feed speed meter always displays...

  • Page 28: Section 6 − Maintenance &Troubleshooting

    SECTION 6 − MAINTENANCE &TROUBLESHOOTING 6-1. Routine Maintenance Maintain more often Y Disconnect power during severe conditions. before maintaining. 3 Months Replace unreadable labels Repair or replace cracked weld cable Clean and tighten weld terminals 6 Months Remove drive roll and Blow out or vacuum inside.

  • Page 29: Changing Drive Roll And Wire Inlet Guide

    6-3. Changing Drive Roll and Wire Inlet Guide Securing Screw Inlet Wire Guide Loosen screw. Slide tip as close to drive rolls as possible without touching. Tighten screw. Drive Roll The drive roll consists of two different sized grooves. stamped markings on the end surface of the drive roll refers to the groove on the opposite side of the drive roll.

  • Page 30: Removing Knob From Front Panel

    6-5. Removing Knob From Front Panel Y Turn Off power. Front Panel Knob Spring Clip Control Shaft Slot Rotate knob to allow access to slot. Insert Allen wrench (or stiff piece of wire) into slot, and while depressing spring clip, slide knob off control shaft.
  • Page 31 Trouble Remedy Change to correct size drive rolls (see Section 6-3). Readjust drive roll pressure (see Section 4-13). Replace inlet guide, contact tip, and/or liner if necessary (see welding gun Owner’s Manual). Check position of input jumper links (see Section 4-10). Have Factory Authorized Service Agent check main control board.

  • Page 32: Section 7 − Electrical Diagram

    SECTION 7 − ELECTRICAL DIAGRAM Figure 7-1. Circuit Diagram OM-1326 Page 28...
  • Page 33 226 707-A OM-1326 Page 29...

  • Page 34: Section 8 − Mig Welding (Gmaw) Guidelines

    SECTION 8 − MIG WELDING (GMAW) GUIDELINES 8-1. Typical MIG Process Connections Y Weld current can damage electronic parts in vehicles. Disconnect both battery Regulator/ cables before welding on a Flowmeter vehicle. Place work clamp as close to the weld as possible. Shielding Supply Wire Feeder/...

  • Page 35: Typical Mig Process Control Settings

    8-2. Typical MIG Process Control Settings NOTE These settings are guidelines only. Material and wire type, joint design, fitup, position, shielding gas, etc. affect settings. Test welds to be sure they comply to specifications. Material thickness determines weld parameters. 1/8 or Convert Material .125 in Thickness to...

  • Page 36: Holding And Positioning Welding Gun

    8-3. Holding And Positioning Welding Gun NOTE 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. Hold Gun and Control Gun Trigger Workpiece...

  • Page 37: Conditions That Affect Weld Bead Shape

    8-4. Conditions That Affect Weld Bead Shape NOTE 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. ° Push ° Perpendicular Drag GUN ANGLES AND WELD BEAD PROFILES Short Normal Long...

  • Page 38: Gun Movement During Welding

    8-5. Gun Movement During Welding NOTE 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. Stringer Bead − Steady Movement Along Seam Weave Bead −...

  • Page 39: Troubleshooting − Excessive Spatter

    8-8. Troubleshooting − Excessive Spatter Excessive Spatter − scattering of molten metal particles that cool to solid form near weld bead. S-0636 Possible Causes Corrective Actions Wire feed speed too high. Select lower wire feed speed. Voltage too high. Select lower voltage range. Electrode extension (stickout) too long.

  • Page 40: Troubleshooting − Lack Of Penetration

    8-11. Troubleshooting − Lack Of Penetration Lack Of Penetration − shallow fusion between weld metal and base metal. Lack of Penetration Good Penetration S-0638 Possible Causes Corrective Actions Improper joint preparation. Material too thick. Joint preparation and design must provide access to bottom of groove while maintaining proper welding wire extension and arc characteristics.

  • Page 41: Troubleshooting − Waviness Of Bead

    8-14. Troubleshooting − Waviness Of Bead Waviness Of Bead − weld metal that is not parallel and does not cover joint formed by base metal. S-0641 Possible Causes Corrective Actions Welding wire extends too far out of nozzle. Be sure welding wire extends not more than 1/2 in (13 mm) beyond nozzle. Unsteady hand.

  • Page 42: Common Mig Shielding Gases

    8-16. 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 43 Problem Probable Cause Remedy Wire slipping in drive rolls. Adjust pressure setting on wire feed rolls. Replace worn Welding arc not stable. drive rolls if necessary. Wrong size gun liner or contact tip. Match liner and contact tip to wire size and type. Incorrect voltage setting for selected wire feed speed on Readjust welding parameters.

  • Page 44: Section 9 − Parts List

    SECTION 9 − PARTS LIST Hardware is common and not available unless listed. 803 008-B Figure 9-1. Main Assembly OM-1326 Page 40...
  • Page 45 Item Dia. Part Mkgs. Description Quantity Figure 9-1. Main Assembly ....Fig 9-2 . . . BAFFLE, center w/components ........
  • Page 46 Hardware is common and not available unless listed. 803007-E Figure 9-2. Baffle, Center w/Components OM-1326 Page 42...
  • Page 47 Item Dia. Part Mkgs. Description Quantity Figure 9-2. Baffle, Center w/Components (Fig 9-1 Item 1) ....058 427 . . . RING, retaining spool ..........
  • Page 48 Item Dia. Part Mkgs. Description Quantity Figure 9-3. Panel, Front w/Components (Fig 9-1 Item 17) ....208 357 LABEL, nameplate ..........
  • Page 49 Item Dia. Part Mkgs. Description Quantity Figure 9-4. Wire Drive And Gears (Fig 9-2 Item 26) ....602 009 . . . SCREW, .250-20 x 1.25 soc hd gr 8 .
  • Page 50 Item Dia. Part Mkgs. Description Quantity Figure 9-5. Panel, Rear w/Components (Fig 9-1 Item 3) ....148 809 . . . BLADE, fan 9 in 5wg 34deg .309 bore CCW .

  • Page 51: Drive Roll And Wire Guide Kits

    9-6. Drive Roll And Wire Guide Kits Note Base selection of drive rolls upon the following recommended usages: V-Grooved rolls for hard wire. U-Grooved rolls for soft and soft shelled cored wires. U-Cogged rolls for extremely soft shelled wires (usually hard surfacing types). V-Knurled rolls for hard shelled cored wires.
  • Page 52 Notes...
  • Page 53 Notes...
  • Page 54 Notes...
  • Page 55 LIMITED WARRANTY − Subject to the terms and conditions Induction Heating Coils and Blankets, Cables, and Call below, Miller Electric Mfg. Co., Appleton, Wisconsin, warrants to Non-Electronic Controls 1-800-4-A-MILLER its original retail purchaser that new Miller equipment sold after APT &...
  • Page 56 Contact the Delivering Carrier to: 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. © PRINTED IN USA 2007 Miller Electric Mfg. Co. 2007−01...

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