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  4. MW250
  5. Owner's Manual

MAC TOOLS MW250 Owner's Manual

Summary of MW250

  • Page 1

    Cover1 5/92* − st-157 072-a printed in usa important: read and understand the entire contents of this manual, with special emphasis on the safety material throughout the manual, before installing, operating, or maintaining this equipment. This unit and these instructions are for use only by persons ...

  • Page 3: Warning

    Arc welding safety precautions warning protect yourself and others from possible serious injury or death. Keep children away. Pacemaker wearers keep away until consulting your doctor. In welding, as in most jobs, exposure to certain hazards occurs. Welding is safe when precautions are taken. The saf...

  • Page 4: Emf Information

    Cylinders can explode if damaged. Shielding gas cylinders contain gas under high pressure. If damaged, a cylinder can explode. Since gas cylinders are normally part of the welding process, be sure to treat them carefully. 1. Protect compressed gas cylinders from excessive heat, mechanical shocks, an...

  • Page 5

    Om-154 501 page 1 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 safety alert symbol 2 signal word warning means possible death or serious injury can happen. Caution mea...

  • Page 6: Caution

    Om-154 501 page 2 2-1. Volt-ampere curves ssb1.1 10/91 − sb-049 424-d 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. Figure 2-1. Volt-ampere curves 2-2. Duty cycle cauti...

  • Page 7: Section 3 − Installation

    Om-154 501 page 3 section 3 − installation 3-1. Installing work clamp 1 work cable 2 boot slide boot onto work cable. Route cable out front panel opening from inside. 3 negative (−) output terminal connect cable to terminal and cover connection with boot. 4 hardware 5 work clamp route cable through ...

  • Page 8: Warning

    Om-154 501 page 4 3-2. Installing gas supply warning cylinders can explode if damaged. • keep cylinders away from welding and other electrical circuits. • never touch cylinder with welding electrode. • always secure cylinder to running gear, wall, or other stationary support. Buildup of shielding ga...

  • Page 9: Warning

    Om-154 501 page 5 3-3. Gun polarity connections warning electric shock can kill. • do not touch live electrical parts. • turn off welding power source, and disconnect input power before inspecting or installing. Swarn1.1 2/93 1 polarity changeover label 2 wire drive assembly 3 positive (+) output te...

  • Page 10: Warning

    Om-154 501 page 6 table 3-1. Electrical service requirements input voltage 200 230 input amperes at rated output 46 40 max recommended standard fuse or circuit breaker rating in amperes 70 60 min input conductor size in awg/kcmil 8 8 max recommended input conductor length in feet (meters) 89 (27) 11...

  • Page 11

    Om-154 501 page 7 b. Connecting input power have only qualified persons make this installation. 1 line disconnect device of proper rating 2 230 volts ac wall receptacle 3 input conductors 4 grounding conductor select size and length using table 3-1. Conductor rating must comply with national, state,...

  • Page 12: Warning

    Om-154 501 page 8 3-6. Installing wire spool and adjusting hub tension turn off unit. 1 wire spool 2 gun contact tip if necessary, cut welding wire off at contact tip, and retract wire onto spool and secure. 3 retaining ring 4 compression spring remove ring and pull off spool. Compression spring is ...

  • Page 13

    Om-154 501 page 9 1 wire spool 2 welding wire 3 inlet wire guide 4 pressure adjustment knob 5 drive roll 6 outlet wire guide 7 gun conduit cable lay gun cable out straight. 4 7 3 5 6 2 1 ref. St-801 103-b / st-154 251 / s-0627-a 6 in (150 mm) 4 in (102 mm) tighten wood open pressure assembly. Pull a...

  • Page 14: Section 4 − Operation

    Om-154 501 page 10 section 4 − operation warning electric shock can kill. • always wear dry insulating gloves. • insulate yourself from work and ground. • do not touch live electrical parts. • keep all panels and covers securely in place. Fumes and gases can be hazardous to your health. • keep your ...

  • Page 15

    Om-154 501 page 11 1 wire speed control use control to set wire feed speed. 2 voltage control use control and voltage range se- lector (see figure 4-2) to set arc voltage. Step 6 of low range and step 1 of high range overlap. 3 pilot light 4 power switch use switch to turn unit on and off. The pilot...

  • Page 16: Warning

    Om-154 501 page 12 section 5 − maintenance & troubleshooting warning electric shock can kill. • do not touch live electrical parts. • turn off welding power source, and disconnect input power before inspecting, maintaining, or servicing. Hot parts can cause severe burns. • allow cooling period befor...

  • Page 17

    Om-154 501 page 13 5-2. Overload protection read safety blocks at start of section 5 before proceeding. Warning a. Circuit breaker cb1 ref. St-801 103-b 1 circuit breaker cb1 2 pilot light if cb1 opens, pilot light goes out, and wire feed stops. Check gun lin- er for blockage or kinks, and check for...

  • Page 18

    Om-154 501 page 14 5-3. Changing drive rolls and wire inlet guide st-150 227-c 1 securing screw 2 inlet wire guide loosen screw. Slide tip as close to drive rolls as possible without touching. Tighten screw. 3 anti-wear guide install guide as shown. 4 drive roll install correct drive roll for wire s...

  • Page 19

    Om-154 501 page 15 5-5. Gun maintenance read safety blocks at start of section 5 before proceeding. Warning flying metal chips and dirt can cause injury and damage equipment. • point gun away from people and in a safe direction when blowing out with compressed air. Swarn10.1 10/91 turn off unit and ...

  • Page 20

    Om-154 501 page 16 5-6. Troubleshooting read safety blocks at start of section 5 before proceeding. Warning welding trouble remedy section no weld output; wire does not feed. Secure power cord plug in receptacle. 3-5 reset circuit breaker cb1. Replace fuse f1 and/or f2. 5-2 replace building line fus...

  • Page 21: Section 7 − Parts List

    Om-154 501 page 17 section 7 − parts list 1 2 fig 7−2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 18 19 20 21 22 fig 7−4 st-155 610-d 17 figure 7-1. Main assembly note: all items indented by a dot(s) are included with the item listed directly above. Description part no. Item no. Part no. Item no. Description...

  • Page 22

    Om-154 501 page 18 st-155 609-c 1 fig 7-3 2 3 4 6 7 8 9 10 11 12 13 14 12 11 16 17 18 19 20 21 24 25 28 29 30 32 23 24 27 31 22 15 5 figure 7-2. Baffle w/components (fig 7-1 item 2) note: all items indented by a dot(s) are included with the item listed directly above. Description part no. Item no. P...

  • Page 23

    Om-154 501 page 19 st-148 529-c 1 2 3 4 5 6 7 8 9 11 10 12 13 15 17 18 19 16 20 21 22 23 14 see table 7-1 for drive roll & wire drive kits figure 7-3. Wire drive and gears (fig 7-2 item 1) description part no. Item no. Part no. Item no. Description part no. Item no. Description 1 602 009 screw, .250...

  • Page 24

    Om-154 501 page 20 1 110 793 handle assembly 2 110 780 nut, m 10 x 1 3 175 180 head tube 4 175 177 diffusor 5 175 175 holder, tip recessed 5 ♦ 175 176 holder, tip flush 6 ♦ 175 230 contact tip, .025 (10pk) 6 ♦ 175 231 contact tip, .030 (10pk) 6 175 232 contact tip, .035 (10pk) 6 ♦ 175 233 contact ti...

  • Page 25

    Om-154 501 page 22 notes.

  • Page 26

    Om-154 501 page 23 notes.

  • Page 27

    Effective january 1, 1997 (equipment with a serial number preface of “kh” or newer) this limited warranty supersedes all previous manufacturers warranties and is exclusive with no other guarantees or warranties expressed or implied. Limited warranty − subject to the terms and conditions below, warra...

  • Page 28: Resources Available

    Printed in usa model name serial/style number purchase date (date which equipment was delivered to original customer.) distributor address city state zip please complete and retain with your personal records. Always provide model name and serial/style number. Contact your distributor for: welding su...