Owner`s manual

ManualsBrandsMiller Electric ManualsDo-It-Yourself toolsMT-24 F-25-1

cover 8/92 − ST-157 356 PRINTED IN USA

Read and follow these instructions and all

safety blocks carefully.

Have only trained and qualified persons

install, operate, or service this unit.

Call your distributor if you do not understand

the directions.

Give this manual to the operator.

For help, call your distributor

or: MILLER ELECTRIC Mfg. Co., P.O. Box

1079, Appleton, WI 54912 414-734-9821

OWNER’S

MANUAL

March 1993 Form: OM-207

Effective With Serial No. KD400224

Maxstar 91

CC/DC Welding Power Source

For GTAW Welding

90 Amperes, 14 Volts DC At 20% Duty Cycle

Uses Single-Phase Input Power

Thermostat Protection Against Overheating

Touch Start For GTAW Welding

14-Pin Remote Control Receptacle

Summary of content (34 pages)

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March 1993 Form: OM-207 Effective With Serial No. KD400224 OWNER’S MANUAL Maxstar 91 CC/DC Welding Power Source For GTAW Welding 90 Amperes, 14 Volts DC At 20% Duty Cycle Uses Single-Phase Input Power Thermostat Protection Against Overheating Touch Start For GTAW Welding 14-Pin Remote Control Receptacle Read and follow these instructions and all safety blocks carefully. cover 8/92 − ST-157 356 Give this manual to the operator.
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TABLE OF CONTENTS SECTION 1 − SAFETY INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 SECTION 2 − SPECIFICATIONS 2-1. 2-2. Volt-Ampere Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Duty Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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SECTION 1 − SAFETY INFORMATION mod1.1 2/93 Read all safety messages throughout this manual. Obey all safety messages to avoid injury. Learn the meaning of WARNING and CAUTION. 1 2 2 WARNING • Do not touch live electrical parts. • Disconnect input power before MOVING PARTS can injure. • Keep away from moving parts. • Keep all panels and covers closed 4 installing or servicing. when operating. 5 READ SAFETY BLOCKS at start of Section 3-1 before proceeding.
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2-1. Volt-Ampere Curves The volt-ampere curves show the minimum and maximum voltage and amperage output capabilities of the welding power source. Curves of other settings fall between the curves shown. ssb1.1 10/91 − SA-156 101 Figure 2-1. Volt-Ampere Curves 2-2. Duty Cycle CAUTION EXCEEDING DUTY CYCLE RATINGS will damage unit. • Do not exceed indicated duty cycles. warn7.1 2/92 Duty cycle is how long the unit can operate within a ten minute period without causing overheating or damage.
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SECTION 3 − INSTALLATION 3-1. Typical Process Connections Remote Control GTAW 14 Pin Welding Power Source HF Unit 14 Pin Work GTAW Pulse Control Scratch Start Pulsed GTAW Or GTAW Welding Power Source Work Figure 3-1. Typical Process Connections 3-2. Selecting A Location And Moving Welding Power Source WARNING ELECTRIC SHOCK can kill. • • Do not touch live electrical parts. Disconnect input power conductors from deenergized supply line BEFORE moving welding power source.
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Table 3-1. Weld Cable Size* Total Cable (Copper) Length In Weld Circuit Not Exceeding 100 ft (30 m) Or Less Welding Amperes 10 To 60% Duty Cycle 60 Thru 100% Duty Cycle 100 150 200 4 3 3 4 3 2 150 ft (45 m) 200 ft (60 m) 250 ft (70 m) 300 ft (90 m) 350 ft (105 m) 400 ft (120 m) 1/0 3/0 4/0 1/0 3/0 4/0 10 Thru 100% Duty Cycle 4 2 1 3 1 1/0 2 1/0 2/0 1 2/0 3/0 *Weld cable size (AWG) is based on either a 4 volts or less drop or a current density of not more than 300 circular mils per ampere.
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3-4. Connecting To Weld Output Receptacles WARNING ELECTRIC SHOCK can kill; ARCING can burn skin or damage electrical equipment. • • • • Do not touch live electrical parts. Turn Off welding power source before making any weld output connections. Do not change position of welding cable connectors while welding. Be sure connectors are secure in receptacles before welding. swarn12.
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3-6. Connecting Input Power WARNING ELECTRIC SHOCK can kill. • • • • Do not touch live electrical parts. Turn Off welding power source, and disconnect input power before inspecting or installing. Have only qualified persons install unit. Installation must meet National Electrical Code and all other codes. 1 2 swarn3.1 2/93 1 115 VAC Cord/Plug 2 115 VAC Grounded Receptacle An individual branch circuit capable of carrying 25 amperes, and protected by fuses or circuit breaker is required.
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1 2 3 1 Insulating Gloves 2 Safety Glasses With Side Shields 3 Welding Helmet Wear dry insulating gloves, safety glasses with side shields, and a welding helmet with a correct shade of filter (see ANSI Z49.1). sb3.1 10/91 Figure 4-2. Safety Equipment 1 1 Tools Needed: Work Clamp Connect work clamp to a clean, paint-free location on workpiece, as close to weld area as possible. Use wire brush or sandpaper to clean metal at weld joint area. Use chipping hammer to remove slag after welding. sb4.
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1 Amperage Control Switch Use switch to select way of controlling amperage adjustment. For front panel control, place switch in Panel position. 1 For remote control, place switch in Remote 14 position (see Section 3-5). See Example below. 2 Remote Foot Control 3 Remote Hand Dial 4 Remote Hand Control EXAMPLE Of Combination Remote Amperage Control 3 4 Unit Mimimum 2 Control Setting (50 A) Set Switches Set Control Adjust Remote Control ST-159 059 / S-0769 / S-0774 Figure 4-6.
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NOTE Touch Start switch must be in Off position when using a High-Frequency unit with this welding power source. 1 Touch Start Switch Use switch to select touch start On or Off. 1 2 3 1−2 Seconds “Touch” Do NOT Strike Like A Match! With touch start On, start an arc in GTAW welding as follows: 2 GTAW Electrode 3 Workpiece Touch tungsten electrode to workpiece at weld start point, hold electrode to workpiece for 1-2 seconds, and slowly lift electrode. An arc will form when electrode is lifted.
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Install & Connect Equipment Install HighFrequency Unit If Applicable Turn On Shielding Gas Select Tungsten (See Section 7) Turn On HighFrequency Unit If Applicable Insert Tungsten Into Torch Turn On Welding Power Source Put On Personal Safety Equipment Set Controls Begin Welding ssb8.1* 12/92 Figure 4-10. Sequence Of Gas Tungsten Arc Welding (GTAW) SECTION 5 − MAINTENANCE & TROUBLESHOOTING WARNING E L E CT RI C SHO CK can ki l l ; SIGNIFICANT DC VOLTAGE exists after removal of input power.
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5-2. Measuring Input Capacitor Voltage READ SAFETY BLOCKS at start of Section 5 before proceeding. WARNING Significant DC voltage can remain on capacitors after unit is Off. Always check capacitors as shown to be sure they have discharged before working on unit. Turn Off welding power source and disconnect input power. Remove wrapper. 1 3 Input Capacitor C1 2 Input Capacitor C2 3 Voltmeter Check input capacitors as shown.
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5-5. Troubleshooting WARNING E L E CT RI C SHO CK can ki l l ; SIGNIFICANT DC VOLTAGE exists after removal of input power. • • MOVING PARTS can cause injury. • Do not touch live electrical parts. Turn Off welding power source, disconnect input power, wait 60 seconds, measure voltage on input capacitors according to Section 5-2, and wait for voltage to drop to zero before inspecting, maintaining, or servicing. STATIC ELECTRICITY can damage parts on circuit boards. • HOT PARTS can cause severe burns.
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Figure 6-1.
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Figure 6-2.
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SD-156 723-A OM-207 Page 15
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SECTION 7 − GTAW METHODS mod9.1 3/93 NOTE For additional information, see your distributor for a handbook on the Gas Tungsten Arc Welding (GTAW) process. Wear clean gloves to prevent contamination of tungsten electrode. 7-1. Selecting Tungsten Electrode Table 7-1.
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7-2. Preparing Tungsten 1 1-1/2 Times Electrode Diameter 1 Tungsten Electrode 2 Balled End Ball end of tungsten before welding by applying either an ac amperage slightly higher than what is recommended for a given electrode diameter (see Table 7-1), or a dc electrode positive amperage. 2 Ref. S-0161 Figure 7-1. Preparing Tungsten For AC Or DC Electrode Positive (DCEP) Welding CAUTION FLYING SPARKS AND HOT METAL can cause injury and start fires.
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7-3. Gas Tungsten Arc Welding (GTAW) Techniques 1 3 Workpiece Make sure workpiece is clean before welding. 2 2 Work Clamp Place as close to the weld as possible. 4 90° 3 Torch 4 Filler Rod (If Applicable) 5 Tungsten Electrode Select and prepare tungsten according to Sections 7-1 and 7-2. 1 Tungsten extension is the distance the tungsten extends out gas cup of torch. Arc length is the distance from the tungsten to the workpiece.
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7-4. Weld Joint Positions 90° Butt Weld And Stringer Bead 70° 20° 20° “T” Joint 70° 10° 20° 40° Lap Joint 70° 20° 30° 90° Corner Joint 70° 20° ST-162 003 / S-0792 Figure 7-5.
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NOTES OM-207 Page 20
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37 38 39 41 Includes Item 41 40 42 43 1 36 35 2 44 34 46 45 3 33 47 48 4 18 31 30 29 28 27 26 6 Figure 8-1.
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Item No. Dia. Mkgs. Part No. Description Quantity Figure 8-1. Main Assembly . . . 1 . . . . . . . . . . . . . . . . 126 416 . . HANDLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . 2 . . . . . . . . . . . . . . . . 126 415 . . CLAMP, saddle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . 3 . . . . . . . . . . . . . . . . 134 327 . . LABEL, warning general precautionary . . . . . . . . . . . . . .
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Item No. Dia. Mkgs. Part No. Description Quantity Figure 8-1. Main Assembly . . . 46 . . . . . . C1,2 . . . . . . . . 47 . . . . . . C12 . . . . . . . . 48 . . . . . . C13 . . . . . . . . 49 . . . . . . . . . . . . . . . . . . . 50 . . . . . . C14 . . . . . . . . 50 . . . . . . C15 . . . . . . . . 50 . . . . . . C16 . . . . . . . . 50 . . . . . . C17 . . . . . . . . 51 . . . . . . RC7 . . . . . ...................... ...................... ...................... ...................... .................
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Item No. Dia. Mkgs. Part No. Description Quantity Figure 8-2. Module, Power & Diode (Fig 8-1 Items 13 & 16) . . . 1 . . . . . . DM1 . . . . . 155 803 . . MODULE, diode (consisting of) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . . . . . C9,10 . . . . 098 325 . . . . CAPACITOR, polyp film .027uf 630V . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . . . . . . D1,2 . . . . . 151 431 . . . . KIT, diode ultra fast recovery . . . . . . . . . . . . . . . . . . . . . . . . . . .
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OPTIONS AND ACCESSORIES BACKLIT LCD METER KIT (#042 881 Factory) (#042 614 Field) A presettable, lighted digital display meter. Meter displays preset amperage, weld amperage, or weld voltage. AMTV REMOTE CONTACTOR AND CURRENT CONTROL (#152 608) Fastens to TIG torch handle using velcro strips. UNIVERSAL LARGE CYLINDER CART (#042 934) Maxstar can mount on this cart along with argon cylinder. Will accommodate 6 to 9 in. (152 to 228 mm) diameter, and 24 to 56 in. (610 to 1422 mm) high.
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OPTIONS AND ACCESSORIES For Total TIG system, select one each of the following items: • Welding power source • TIG torch (recommended torches listed below) • TIG kit (see kits listed below) • Remote control (optional) • Snap Start (optional) TIG TORCHES AND CONNECTING KITS For hand−held, manual applications. For complete information on all Miller TIG torches and accessories, see Literature Index No. TG/1.0.