Miller STH 270 Owner's Manual
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Miller STH 270 Owner's Manual

Miller STH 270 Owner's Manual

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STH 270
CE
OM-265 270A
2013−11
Processes
TIG (GTAW) Welding
Stick (SMAW) Welding
Description
Arc Welding Power Source

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  • Page 1 OM-265 270A 2013−11 Processes TIG (GTAW) Welding Stick (SMAW) Welding Description Arc Welding Power Source STH 270...
  • Page 2 From Miller to You Thank you and congratulations on choosing Miller. Now you can get the job done and get it done right. We know you don’t have time to do it any other way. That’s why when Niels Miller first started building arc welders in 1929, he made sure his products offered long-lasting value and superior quality.

  • Page 3: Table Of Contents

    ................3-3. Specifications For STH 270 .
  • Page 4 Council Directive(s) and Standard(s). Product/Apparatus Identification: Product Stock Number STH 270 059016024 Council Directives: ·2006/95/EC Low Voltage ·2004/108/EC Electromagnetic Compatibility ·2011/65/EU Restriction of the use of certain hazardous substances in electrical and electronic equipment Standards: ·IEC 60974­1 Arc Welding Equipment ­...

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

    SECTION 1 − SAFETY PRECAUTIONS - READ BEFORE USING som 2013−09 Protect yourself and others from injury — read, follow, and save these important safety precautions and operating instructions. 1-1. Symbol Usage DANGER! − Indicates a hazardous situation which, if Indicates special instructions.

  • Page 6: Noise Can Damage Hearing

    D Remove stick electrode from holder or cut off welding wire at FUMES AND GASES can be hazardous. contact tip when not in use. D Wear body protection made from durable, flame−resistant material Welding produces fumes and gases. Breathing (leather, heavy cotton, wool). Body protection includes oil-free these fumes and gases can be hazardous to your clothing such as leather gloves, heavy shirt, cuffless trousers, high health.

  • 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 injure. 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: California Proposition 65 Warnings

    1-4. California Proposition 65 Warnings Welding or cutting equipment produces fumes or gases This product contains chemicals, including lead, known to which contain chemicals known to the State of California to the state of California to cause cancer, birth defects, or other cause birth defects and, in some cases, cancer.

  • Page 9: Section 2 − Definitions

    SECTION 2 − DEFINITIONS 2-1. Additional Safety Symbols And Definitions Some symbols are found only on CE products. Warning! Watch Out! There are possible hazards as shown by the symbols. Safe1 2012−05 Do not discard product (where applicable) with general waste. Reuse or recycle Waste Electrical and Electronic Equipment (WEEE) by disposing at a designated collection facility.
  • Page 10 Do not weld on drums or any closed containers. Safe16 2012−05 Do not remove or paint over (cover) the label. Safe20 2012−05 Wear hat and safety glasses. Use ear protection and button shirt collar. Use welding helmet with correct shade of filter. Wear complete body protection.

  • Page 11: Miscellaneous Symbols And Definitions

    2-2. Miscellaneous Symbols And Definitions Gas Tungsten Arc Shielded Metal Arc Amperes Output/On Welding (GTAW) Welding (SMAW) 3 Phase Static Frequency Volts Voltage Input Converter-Transformer-Rectifier Lift-Arc Start Voltage Output Remote (GTAW) Protective Earth Process High Temperature Hot Start (Ground) Percent Positive Negative Alternating...

  • Page 12: Section 3 − Specifications

    IP Rating: 23S.This equipment is designed for outdoor use. It may be stored, but is not intended to be used outside during precipitation unless sheltered. Operating temperature Range: 14° F (-10° C) to 104° F (40° C). Ratings were developed at an ambient temperature of 20° C to 25° C. 3-3. Specifications For STH 270 Input Power Rated Welding Output Max.

  • Page 13: Volt-Ampere Curves

    3-4. Volt-Ampere Curves Volt-ampere curves show minimum and maximum voltage and amperage output capabilities of welding power source. Curves of other settings fall between curves shown. 10 20 30 40 50 60 70 80 90 100 120 130140150 160170180190200 210220230240250 260270280 DC Amperage (A) 3-5.

  • Page 14: Section 4 − Installation

    SECTION 4 − INSTALLATION 4-1. Serial Number And Rating Label Location The serial number and rating information for the power source is located on the bottom of the machine. Use the rating labels to determine input power requirements and/or rated output. For future reference, write serial number in space provided on back cover of this manual. 4-2.

  • Page 15: Weld Output Terminals And Selecting Cable Sizes

    4-3. Weld Output Terminals And Selecting Cable Sizes* NOTICE − The Total Cable Length in Weld Circuit (see table below) is the combined length of both weld cables. For example, if the power source is 30 m (100 ft) from the workpiece, the total cable length in the weld circuit is 60 m (2 cables x 30 m). Use the 60 m (200 ft) column to determine cable size.

  • Page 16: Tig Lift-Arc Dcen (Direct Current Electrode Negative) Weld Output Connections

    4-5. TIG Lift-Arc DCEN (Direct Current Electrode Negative) Weld Output Connections Turn off power before mak- ing connections. Positive (+) Weld Output Terminal Work Lead Connect work lead to positive weld output terminal. Negative (−) Weld Output Terminal Electrode Holder Connect TIG torch to negative weld output terminal.

  • Page 17: Stick Dcep (Direct Current Electrode Positive)Weld Output Connections

    4-7. Stick DCEP (Direct Current Electrode Positive)Weld Output Connections Turn off power before mak- ing connections. Negative (−) Weld Output Terminal Work Lead Connect work lead to negative weld output terminal. Positive (+) Weld Output Terminal Electrode Holder Connect electrode holder to posi- tive weld output terminal.

  • Page 18: Connecting 3-Phase Input Power

    4-9. Connecting 3-Phase Input Power = GND/PE Earth Ground Tools Needed: input2 2012−05 − 956172131_1-A OM-265 270 Page 14...

  • Page 19: Connecting To 3-Phase Engine Generator W/400 Volt Output

    4-9. Connecting 3-Phase Input Power (Continued) See rating label on unit and check input volt- Connect green or green/yellow grounding Installation must meet all National and age available at site. conductor to disconnect device grounding ter- Local Codes − have only qualified per- minal first.

  • Page 20: Section 5 − Operation

    SECTION 5 − OPERATION 5-1. Controls Output Control Selector Switch Process Selector Switch 17 Remote 14 Receptacle If desired, connect a remote control to the See Section 5-2 and/or 5-3. Use switch to select way of controlling unit Remote 14 receptacle See Section 4-4. output.

  • Page 21: Preparing Unit For Stick (Smaw) Welding

    5-2. Preparing Unit For Stick (SMAW) Welding Positive Weld Output Terminal Remote 14 Receptacle Negative Weld Output Terminal Amperage/Parameter Adjustment Control Ammeter/Voltage Display (Meter) Process Selector Switch MENU/VRD Selector Switch Hot Start/Arc Force Light Welding Amperage Light Prepare unit for Stick welding as follows: Connect electrode holder and work clead (see Section 4-7) .

  • Page 22: Preparing Unit For Tig (Gtaw) Welding

    5-3. Preparing Unit For TIG (GTAW) Welding Positive Weld Output Terminal Remote 14 Receptacle Negative Weld Output Terminal Amperage/Parameter Adjustment Control Ammeter/Voltage/Parameter Display Meter Process Selector Switch Menu/VRD Selector Switch Prepare Unit For TIG Welding As Follows: connect electrode holder and work lead (see Section 4-5) .

  • Page 23: Amperage Control

    5-4. Amperage Control Amperage Control Rotate control clockwise to in- crease amperage (5-270 amps). Amperage Indicator Light 956172131_5-A 5-5. Trigger Mode Selection Process Selector Switch Rotate knob clockwise to increase amperage (0-270 amps). Trigger Mode Selector Switch 2T and 4T are used with the TIG Current (A) process.

  • Page 24: Sequence Control Settings

    5-6. Sequence Control Settings Hot Start/Arc Force Amperage Control Control Amperage/Parameter Adjustment Slope Up Time Final Current Control Is the amperage to which weld amperage Is the amount of time it takes to slope up/ Ammeter/Voltage/Parameter Display has sloped up/down to. down from initial amperage to weld amper- (Meter) age.

  • Page 25: Pulser Control Settings

    5-7. Pulser Control Settings Amperage/Parameter Adjustment Pulser LEDs are controlled in width, height, and frequen- Control cy, forming pulses of weld output. These Background Current pulses and the lower amperage level be- Ammeter/Voltage/Parameter Display Background Current controls the low pulse tween them (called the background cur- (Meter) of the weld amperage, which cools the weld...

  • Page 26: Hf Current Settings

    5-8. HF Current Settings Ihf: HF Current Iweld: Welding Current Current (A) Ihf<Iweld IWeld HF Current Setting (A) Automatic HF Current (A) Slope Up Time Time Current (A) HF Current HF Current HF Current Range Value Is Selected Automatically Set For 25A For 20 ms Ihf>Iweld IWeld Time...

  • Page 27: Lift-Arc Start Procedure

    5-9. Lift-Arc Start Procedure Lift-Arc Start With Lift-Arct selected, start arc as follows: TIG Electrode Workpiece Turn gas on. Touch tungsten elec- trode to workpiece at weld start point. Hold electrode to work- piece for 1-2 seconds, and slowly Lift-Arc Start Method lift electrode.

  • Page 28: Section 6 − Maintenance And Troubleshooting

    SECTION 6 − MAINTENANCE AND TROUBLESHOOTING 6-1. Routine Maintenance Disconnect power before maintaining. Maintain more often during severe conditions. A. Welding Power Source n = Check Z = Change ~ = Clean Δ = Repair l = Replace * To be done by Factory Authorized Service Agent Every Months nl Labels...

  • Page 29: Troubleshooting

    6-3. Troubleshooting Trouble Remedy No weld output; unit completely Place line disconnect switch in On position (see Section 4-9). inoperative. Check and replace line fuse(s), if necessary, or reset circuit breaker (see Section 4-9). Check for proper input power connections (see Section 4-9). No weld output;...

  • Page 30: Section 7 − Electrical Diagrams

    SECTION 7 − ELECTRICAL DIAGRAMS Figure 7-1. Circuit Diagram 956172132_A OM-265 270 Page 26...

  • Page 31: Section 8 − High Frequency

    SECTION 8 − HIGH FREQUENCY 8-1. Welding Processes Requiring High Frequency High-Frequency Voltage TIG − helps arc jump air gap between torch and workpiece and/ or stabilize the arc. Work high_freq 5/10 − S-0693 8-2. Installation Showing Possible Sources Of HF Interference Weld Zone 11, 12 50 ft...

  • Page 32: Recommended Installation To Reduce Hf Interference

    8-3. Recommended Installation To Reduce HF Interference Weld Zone 50 ft (15 m) 50 ft (15 m) Ground all metal ob- jects and all wiring in welding zone using #12 AWG wire. Ground workpiece if required by Nonmetal codes. Building Best Practices Followed Metal Building Ref.

  • Page 33: Section 9 − Selecting And Preparing A Tungsten For Dc Or Ac Welding With Inverter Machines

    SECTION 9 − SELECTING AND PREPARING A TUNGSTEN FOR DC OR AC WELDING WITH INVERTER MACHINES gtaw_Inverter_2011-06 Whenever possible and practical, use DC weld output instead of AC weld output. 9-1. Selecting Tungsten Electrode ( Wear Clean Gloves To Prevent Contamination Of Tungsten Not all tungsten electrode manufacturers use the same colors to identify tungsten type.

  • Page 34: Section 10 − Guidelines For Tig Welding (Gtaw)

    SECTION 10 − GUIDELINES FOR TIG WELDING (GTAW) 10-1. Positioning The Torch Grinding the tungsten electrode produces dust and flying sparks which can cause injury and start fires. Use local exhaust (forced ventilation) at the grinder or wear an approved respirator. Read MSDS for safety information.

  • Page 35: Torch Movement During Welding

    10-2. Torch Movement During Welding Tungsten Without Filler Rod ° Welding direction Form pool Tilt torch Move torch to front of pool. Repeat process. Tungsten With Filler Rod ° ° Welding direction Form pool Tilt torch Add filler metal Remove rod Move torch to front of pool.

  • Page 36: Section 11 − Stick Welding (Smaw) Guidelines

    SECTION 11 − STICK WELDING (SMAW) GUIDELINES 11-1. Stick Welding Procedure Weld current starts when electrode touches work- piece. Weld current can damage electronic parts in vehicles. Disconnect both battery Equipment Needed: Tools Needed: cables before welding on a vehicle. Place work clamp as close to the weld as possible.

  • Page 37: Electrode And Amperage Selection Chart

    11-2. Electrode and Amperage Selection Chart 6010 DEEP 3/32 MIN. PREP, ROUGH HIGH SPATTER 6011 DEEP 6010 5/32 & 6013 EP,EN GENERAL 3/16 6011 7/32 SMOOTH, EASY, 7014 EP,EN FAST 1/16 LOW HYDROGEN, 7018 5/64 STRONG 3/32 FLAT SMOOTH, EASY, 7024 EP,EN HORIZ...

  • Page 38: Positioning Electrode Holder

    11-4. Positioning Electrode Holder End View Of Work Angle Side View Of Electrode Angle After learning to start and hold an arc, practice running beads of weld metal on flat plates using a full electrode. ° ° Hold the electrode nearly per- pendicular to the work, although °...

  • Page 39: Conditions That Affect Weld Bead Shape

    11-7. Conditions That Affect Weld Bead Shape Weld bead shape is affected electrode angle, length, travel speed, and thick- ness of base metal. Correct Angle ° - ° Angle Too Large Angle Too Small Electrode Angle Drag Spatter Arc Length Normal Too Long Too Short...
  • Page 40 11-10. Welding Groove (Butt) Joints Tack Welds Prevent butt joint distortion by tack welding the materials in position before final weld. Workpiece distortion occurs when heat is applied locally to a joint. One side of a metal plate will “curl” up toward the weld.
  • Page 41 11-12. Weld Test Vise Weld Joint Hammer Strike the weld joint in the direction shown. A good weld bends over but does not break. If the weld breaks, examine it to determine the cause. If the weld is porous (many holes), the arc length was probably too long.
  • Page 42 Lack Of Penetration − shallow fusion between weld metal and base metal. Lack of Penetration Good Penetration Possible Causes Corrective Actions Improper joint preparation. Material too thick. Joint preparation and design must provide access to bottom of groove. Improper weld technique. Keep arc on leading edge of weld puddle.
  • Page 43 Notes OM-265 270 Page 39...

  • Page 44: Section 12 − Parts List

    . . . Label, Side STH 270 ........
  • Page 45 . . . Nameplate, Rear, STH 270 ........
  • Page 46 Notes TM-216 869 Page 42 Dynasty 350/700, Maxstar 350/700...
  • Page 47 Effective January 1, 2013 (Equipment with a serial number preface of MD or newer) This limited warranty supersedes all previous Miller warranties and is exclusive with no other guarantees or warranties expressed or implied. LIMITED WARRANTY − Subject to the terms and conditions 90 Days —...

  • Page 48: Owner's Record

    File a claim for loss or damage during Phone: 39 (0) 2982901 Fax: 39 (0) 298290-203 shipment. email: miller@itw−welding.it For assistance in filing or settling claims, contact your distributor and/or equipment manufacturer’s Transportation Department. © ORIGINAL INSTRUCTIONS − PRINTED IN USA 2013 Miller Electric Mfg. Co. 2013−01...

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