Migmaster 250: Welding Packages

INSTRUCTIONS for F-15-087-E
August, 1997
MIGMASTER 250
WELDING PACKAGES
F-15-087-E
NOTE: This manual is also suitable for use with L-TEC Migmaster 250 package.
These INSTRUCTIONS are for experienced operators. If you are not fully familiar with the principles
of operation and safe practices for electric welding equipment, we urge you to read our booklet,
"Precautions and Safe Practices for Arc Welding, Cutting and Gouging." Form 52-529. Do NOT permit
untrained persons to install, operate, or maintain this equipment. Do NOT attempt to install or operate
this equipment until you have read and fully understand these Instructions. If you do not fully
understand these Instructions, contact your supplier for further information. Be sure to read the
Safety Precautions on page 2 before installing or operating this equipment.
Be sure this information reaches the operator.

You can get extra copies through your supplier.
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USER RESPONSIBILITY
This equipment will perform in conformity with the description thereof contained in this manual and accompanying
labels and/or inserts when installed, operated, maintained and repaired in accordance with the instructions provided.
This equipment must be checked periodically. Defective equipment should not be used. Parts that are broken, missing,
worn, distorted or contaminated should be replaced immediately. Should such repair or replacement become
necessary, the manufacturer recommends that a telephone or written request for service advice be made to the
Authorized Distributor from whom purchased.
This equipment or any of its parts should not be altered without the prior written approval of the manufacturer. The
user of this equipment shall have the sole responsibility for any malfunction which results from improper use, faulty
maintenance, damage, improper repair or alteration by anyone other than the manufacturer or a service facility
designated by the manufacturer.

TABLE OF CONTENTS
SECTION NO. PAGE NO.
SECTION 1 - GENERAL SAFETY RULES FOR WELDING

AND CUTTING ........................................................................................................... 4
GENERAL PRECAUTIONS .................................................................................................. 4

PRECAUTION SYMBOL DEFINITIONS ........................................................................ 5
SECTION II - INTRODUCTION ............................................................................................. 6
2.1 GENERAL .................................................................................................................. 6

2.2 RECEIVING-HANDLING ............................................................................................ 6
2.3 DESCRIPTION, Available Packages/Contents ........................................................... 6
2.4 OPTIONAL ACCESSORIES ....................................................................................... 7
2.5 SAFETY ..................................................................................................................... 9
SECTION III - INSTALLATION ............................................................................................. 9
3.1 LOCATION ................................................................................................................. 9

3.2 ELECTRICAL INPUT CONNECTIONS ...................................................................... 9
3.3 SECONDARY OUTPUT CONNECTIONS ................................................................ 12
3.4 TORCH CONNECTIONS ......................................................................................... 12
3.5 WIRE FEEDER MECHANISM .................................................................................. 12
3.6 CONNECTION OF THE SHIELD GAS ..................................................................... 13
3.7 WELDING CABLE CONNECTIONS ......................................................................... 14
3.8 ASSEMBLE REAR WHEELS ................................................................................... 14
3.9 INSTALLING OPTIONAL SPOT/STITCH/ANTI-STICK MODULE ............................ 14
3.10 INSTALLING OPTIONAL DIGITAL METER ............................................................. 14
SECTION IV - OPERATION ................................................................................................ 15
4.1 CONTROLS .............................................................................................................. 15

4.2 PROCESS SETUP ................................................................................................... 16
4.3 OPERATING PROCEDURES .................................................................................. 19
SECTION V - SERVICE ...................................................................................................... 22
5.1 MAINTENANCE ....................................................................................................... 22

5.2 INSPECTION AND SERVICE .................................................................................. 22
5.3 TROUBLESHOOTING .............................................................................................. 23
SECTION VI - PARTS ......................................................................................................... 26
6.1 SPARE PARTS ........................................................................................................ 26

6.2 REPLACEMENT PARTS .......................................................................................... 26
6.3 ORDERING .............................................................................................................. 26

SAFETY PRECAUTIONS
WARNING: These Safety Precautions are for 5. Do not use equipment beyond its ratings. For example,
your protection. They summarize precautionary overloaded welding cable can overheat and create a fire
information from the references listed in Addi- hazard.
tional Safety Information section. Before per- 6. After completing operations, inspect the work area to make
forming any installation or operating procedures, be sure to certain there are no hot sparks or hot metal which could
read and follow the safety precautions listed below as well cause a later fire. Use fire watchers when necessary.
as all other manuals, material safety data sheets, labels, etc. 7. For additional information, refer to NFPA Standard 51B,
Failure to observe Safety Precautions can result in injury or "Fire Prevention in Use of Cutting and Welding Processes",
death. available from the National Fire Protection Association,
PROTECT YOURSELF AND OTHERS -- Batterymarch Park, Quincy, MA 02269.
Some welding, cutting, and gouging
processes are noisy and require ear ELECTRICAL SHOCK -- Contact with live
protection. The arc, like the sun, emits electrical parts and ground can cause se-
ultraviolet (UV) and other radiation and vere injury or death. DO NOT use AC weld-
can injure skin and eyes. Hot metal can cause burns. ing current in damp areas, if movement is
Training in the proper use of the processes and equip- confined, or if there is danger of falling.
ment is essential to prevent accidents. Therefore:
1. Be sure the power source frame (chassis) is connected to
1. Always wear safety glasses with side shields in any work the ground system of the input power.
area, even if welding helmets, face shields, and goggles 2. Connect the workpiece to a good electrical ground.
are also required. 3. Connect the work cable to the workpiece. A poor or
2. Use a face shield fitted with the correct filter and cover missing connection can expose you or others to a fatal
plates to protect your eyes, face, neck, and ears from shock.
sparks and rays of the arc when operating or observing 4. Use well-maintained equipment. Replace worn or dam-
operations. Warn bystanders not to watch the arc and not aged cables.
to expose themselves to the rays of the electric-arc or hot 5. Keep everything dry, including clothing, work area, cables,
metal. torch/electrode holder, and power source.
3. Wear flameproof gauntlet type gloves, heavy long-sleeve 6. Make sure that all parts of your body are insulated from
shirt, cuffless trousers, high-topped shoes, and a welding
work and from ground.
helmet or cap for hair protection, to protect against arc
7. Do not stand directly on metal or the earth while working
rays and hot sparks or hot metal. A flameproof apron may
also be desirable as protection against radiated heat and in tight quarters or a damp area; stand on dry boards or
sparks. an insulating platform and wear rubber-soled shoes.
4. Hot sparks or metal can lodge in rolled up sleeves, 8. Put on dry, hole-free gloves before turning on the power.
trouser cuffs, or pockets. Sleeves and collars should be 9. Turn off the power before removing your gloves.
kept buttoned, and open pockets eliminated from the 10. Refer to ANSI/ASC Standard Z49.1 (listed on next page)
front of clothing for specific grounding recommendations. Do not mistake
5. Protect other personnel from arc rays and hot sparks with the work lead for a ground cable.
a suitable non-flammable partition or curtains.
6. Use goggles over safety glasses when chipping slag or ELECTRIC AND MAGNETIC FIELDS — May
grinding. Chipped slag may be hot and can fly far. be dangerous. Electric current flowing
Bystanders should also wear goggles over safety glasses. through any conductor causes localized
Electric and Magnetic Fields (EMF). Weld-
FIRES AND EXPLOSIONS -- Heat from
ing and cutting current creates EMF around
flames and arcs can start fires. Hot slag
welding cables and welding machines.
or sparks can also cause fires and ex-
Therefore:
plosions. Therefore:
1. Welders having pacemakers should consult their physi-
1. Remove all combustible materials well away from the
cian before welding. EMF may interfere with some pace-
work area or cover the materials with a protective non-
flammable covering. Combustible materials include wood, makers.
cloth, sawdust, liquid and gas fuels, solvents, paints and 2. Exposure to EMF may have other health effects which are
coatings, paper, etc. unknown.
2. Hot sparks or hot metal can fall through cracks or crevices 3. Welders should use the following procedures to minimize
in floors or wall openings and cause a hidden smoldering exposure to EMF:
fire or fires on the floor below. Make certain that such A. Route the electrode and work cables together. Secure
openings are protected from hot sparks and metal.“ them with tape when possible.
3. Do not weld, cut or perform other hot work until the B. Never coil the torch or work cable around your body.
workpiece has been completely cleaned so that there are C. Do not place your body between the torch and work
no substances on the workpiece which might produce cables. Route cables on the same side of your body.
flammable or toxic vapors. Do not do hot work on closed D. Connect the work cable to the workpiece as close as
containers. They may explode.
possible to the area being welded.
4. Have fire extinguishing equipment handy for instant use,
such as a garden hose, water pail, sand bucket, or E. Keep welding power source and cables as far away from
portable fire extinguisher. Be sure you are trained in its your body as possible.
use.
4 11/95

FUMES AND GASES -- Fumes and 2. Before performing any maintenance work inside a power
gases, can cause discomfort or harm, source, disconnect the power source from the incoming
particularly in confined spaces. Do electrical power.
not breathe fumes and gases. Shield- 3. Maintain cables, grounding wire, connections, power cord,
ing gases can cause asphyxiation. and power supply in safe working order. Do not operate
Therefore: any equipment in faulty condition.
4. Do not abuse any equipment or accessories. Keep
1. Always provide adequate ventilation in the work area by equipment away from heat sources such as furnaces, wet
natural or mechanical means. Do not weld, cut, or gouge conditions such as water puddles, oil or grease, corrosive
on materials such as galvanized steel, stainless steel, atmospheres and inclement weather.
copper, zinc, lead, beryllium, or cadmium unless positive 5. Keep all safety devices and cabinet covers in position and
mechanical ventilation is provided. Do not breathe fumes in good repair.
from these materials. 6. Use equipment only for its intended purpose. Do not
2. Do not operate near degreasing and spraying operations. modify it in any manner.
The heat or arc rays can react with chlorinated hydrocar-
bon vapors to form phosgene, a highly toxic gas, and ADDITIONAL SAFETY INFORMATION -- For more infor-
other irritant gases. mation on safe practices for electric arc welding and
3. If you develop momentary eye, nose, or throat irritation cutting equipment, ask your supplier for a
while operating, this is an indication that ventilation is not copy of "Precautions and Safe Practices for
adequate. Stop work and take necessary steps to im- Arc Welding, Cutting and Gouging", Form
prove ventilation in the work area. Do not continue to 52-529.
operate if physical discomfort persists.
4. Refer to ANSI/ASC Standard Z49.1 (see listing below) for The following publications, which are available from the
specific ventilation recommendations. American Welding Society, 550 N.W. LeJuene Road, Miami,
FL 33126, are recommended to you:
1. ANSI/ASC Z49.1 - "Safety in Welding and Cutting"
CYLINDER HANDLING -- Cylinders, if 2. AWS C5.1 - "Recommended Practices for Plasma Arc
mishandled, can rupture and violently Welding"
release gas. Sudden rupture of cylin- 3. AWS C5.2 - "Recommended Practices for Plasma Arc
der, valve, or relief device can injure or Cutting"
kill. Therefore: 4. AWS C5.3 - "Recommended Practices for Air Carbon Arc
Gouging and Cutting"
1. Use the proper gas for the process and use the proper 5. AWS C5.5 - "Recommended Practices for Gas Tungsten
pressure reducing regulator designed to operate from the Arc Welding“
compressed gas cylinder. Do not use adaptors. Maintain 6. AWS C5.6 - "Recommended Practices for Gas Metal Arc
hoses and fittings in good condition. Follow manufacturer's Welding"“
operating instructions for mounting regulator to a com- 7. AWS SP - "Safe Practices" - Reprint, Welding Handbook.
pressed gas cylinder. 8. ANSI/AWS F4.1, "Recommended Safe Practices for Weld-
2. Always secure cylinders in an upright position by chain or ing and Cutting of Containers That Have Held Hazardous
strap to suitable hand trucks, undercarriages, benches, Substances."
walls, post, or racks. Never secure cylinders to work
tables or fixtures where they may become part of an This symbol appearing throughout this manual means Atten-
electrical circuit. tion! Be Alert! Your safety is involved.
3. When not in use, keep cylinder valves closed. Have valve
protection cap in place if regulator is not connected.
Secure and move cylinders by using suitable hand trucks. The following definitions apply to DANGER,
Avoid rough handling of cylinders. WARNING, CAUTION found throughout this
4. Locate cylinders away from heat, sparks, and flames. manual:
Never strike an arc on a cylinder.
5. For additional information, refer to CGA Standard P-1,
"Precautions for Safe Handling of Compressed Gases in
Cylinders", which is available from Compressed Gas Used to call attention to immediate haz-
Association, 1235 Jefferson Davis Highway, Arlington, ards which, if not avoided, will result in
VA 22202. immediate, serious personal injury or loss
of life.
EQUIPMENT MAINTENANCE -- Faulty or im-
properly maintained equipment can cause Used to call attention to potential haz-
injury or death. Therefore: ards which could result in personal injury
or loss of life.
1. Always have qualified personnel perform the installation, Used to call attention to hazards which
troubleshooting, and maintenance work. Do not perform could result in minor personal injury.
any electrical work unless you are qualified to perform
such work.

II. INTRODUCTION l One (1), Migmaster 250 Power Supply/Wire Feeder
equipped with a dual-groove feed roll (for .035/.045 wire),
2.1 GENERAL a 6'-0" ft. primary input power cable and plug (plug is
installed for 208/230-V. units only), an input power recep-
This manual has been prepared especially for use in tacle rated @ 50A./250-V. (packed loose for 208/230-V.
familiarizing personnel with the design, installation, op- input packages only), 10-ft. work cable w/clamp, a 6'-0"
eration, maintenance, and troubleshooting of this equip- shielding gas supply hose w/fittings and running gear w/
ment. All information presented here in should be given gas (cylinder) support, as follows:
careful consideration to assure optimum performance of
this equipment. -- Migmaster 250 for 208/230-Volt input .... P/N 32851
-- Migmaster 250 for 208/230/380/400/460/575-Volt
2.2 RECEIVING-HANDLING input ....................................................... P/N 32852
Prior to installing this equipment, clean all packing mate- l One (1), Migmaster 250 Kit as follows:
rial from around the unit and carefully inspect for any -- 12-ft. Kit ................................................. P/N 32993
damage that may have occurred during shipment. Any Includes:
claims for loss or damage that may have occurred in MT-200cc, ready-to-weld, 12-ft. lg. torch
transit must be filed by the purchaser with the carrier. A for .035/.045 wire ....................................... P/N 21116
copy of the bill of lading and freight bill will be furnished R-33-FM-580 Regulator, (F-15-173) ........... P/N 21557
by the carrier on request if occasion to file claim arises. Mig Welding Process Handbook .............. P/N 791F18
When requesting information concerning this equipment, -- 15-ft. Kit ................................................. P/N 32994
it is essential that Part, Serial and Model Numbers of the Includes same accessories as 12-ft. Kit except for torch,
equipment be supplied. which is:
MT-200cc, 15-ft. lg. for .035/.045 wire, ....... P/N 21117
2.3 DESCRIPTION
2.3.2 POWER SUPPLY
The Migmaster 250 is a portable Welding System de-
signed for fine wire, (0.023, 0.030, 0.035 and 0.045 in.) The power supply consists of a tapped single phase
welding using the short arc method, as well as for spray transformer, tap selection switches, secondary contactor,
arc aluminum, short arc and spray arc stainless steel and single phase full wave rectifier, stabilizing reactor, slope
spray arc cored wires. It incorporates a running gear with resistor, filtering capacitors and internal output connec-
provisions for one gas cylinder, and a ST-23A spool-on- tions for polarity reversal.
gun control.
2.3.3 WIRE FEEDER
2.3.1 AVAILABLE PACKAGES AND CONTENTS
The wire feeder pushes 0.023, 0.030, 0.035 and 0.045 in.
The following Migmaster 250 “Consisting of” Packages wire at speeds up to 650 IPM. Dynamic braking prevents
are available: excessive wire overrun. A double grooved drive roll
(0.035 and 0.045 in.) provides a convenient means of
MM-250 for 208/230-V. Input w/12-ft. Kit . P/N 604560 changing the setup for either wire size.
MM-250 for 208/230-V. Input w/15-ft. Kit . P/N 604561
MM-250 for 208/230/380/400/460/575-V. Input w/12-ft. Kit The wire feeder is built into the power supply cabinet, and
.............................................................. P/N 604563 is housed in a compartment separated from the welding
MM-250 for 208/230/380/400/460/575-V. Input w/15-ft. Kit machine components. Machine ventilation is not drawn
.............................................................. P/N 604570 through this compartment, thus helping to keep the wire
and feeding mechanism clean.
Depending on the “primary input voltage” of the MM-250,
and the “torch length”, each package includes the follow-
ing:

TABLE 1. SPECIFICATIONS
POWER SOURCE MIGMASTER 250
Rated Output 250 Amps @ 27 Volts d.c.

Duty Cycle, 208/230V Unit 50% @ 60 Hz.; 40% @ 50 Hz.
208/230/380/400/460/575V Unit 35% for 208 through 400V; 50% for 460 & 575V
Primary Input Single Phase 208/230; 208/230/380/400/460/575 Volts 50 60 Hz
Primary Input Amperes 208-71, 230-62, 380-37,400-36, 460-31, 575-25
Output Current Range 30 to 280 Amps.
Maximum Open Circuit Volts 55 v.d.c.
FEEDER
Feed Type Push

Wire Sizes Hard & Cored 0.023 inch (.6mm) 0.035 inch (.899mm)
0.030 inch (.762mm) 0.045 inch (1.143mm)
Feed Rate 20-650 IPM
MT-200cc TORCH
Cooling Air
Gooseneck Angle 45 degrees
Rated 60% Duty Cycle
(DCRP) Amps: 200 w/Argon Mixtures, 300 w/CO 2
Conduit Length see section 2.3.1
PHYSICAL
Net Weight *210 lbs (95 Kg.)

Height *32.25 inches (819 mm)
Width *19.5 inches (495 mm)
Depth *40.0 inches (1016 mm)
*Includes running gear & bottle tray.
2.3.4 MT-200cc WELDING TORCH (F-15-085), 2.3.6 RUNNING GEAR
The lightweight air cooled welding gun included in se- The Migmaster 250 is equipped with a running gear w/
lected systems is supplied complete and ready to weld swiveled front wheels and a gas cylinder support. The
0.035 in. steel wire. It is built with a one piece service rear wheels are packed loose for shipping, but are easily
conduit and includes a 45 degree gooseneck. Changing installed, see Section 3.8.
the contact tip to 0.045 in. allows the use of the larger
wire. 2.4 OPTIONAL ACCESSORIES
2.3.5 CONTROLS 2.4.1 SPOT/STITCH/ANTI-STICK MODULE, P/N

32858.
The Migmaster 250 System can be used to weld hard and
aluminum wire with an optional ST-23A spool-gun torch. This easy-to-install, plug-in module mounts in place of
An optional spot/stitch control allows a welder to spot or the lower blank cover plate of the upper-right front panel
stitch weld within a range of 0.4 to 3.5 seconds. The built- location in the 250 unit. It enables the operator to use the
in spool-on-gun adaptors and control, when used in 250 for Spot or Stitch or Continuous welding operations.
conjunction with the optional ST-23A torch, permits alu- It also includes an adjustable Anti-Stick feature that
minum wire welding with the machine. allows you to select various wire burnback times to
prevent wire from sticking in the puddle after a weld. For
installation, see Section 3.9 and for operating instruc-
tions see Section 4.2.

If a Spotwelding operation is to be used, it is recom- thirty (30) foot service lines; one is a control cable with
mended that you also order a #12S Spotweld Nozzle, amphenol plug, and the other is a gas and power cable
P/N 999625. with a screw-on connector. For installation and opera-
tion, see Section 4.1.7 and for detailed instruction book-
2.4.2 DIGITAL VOLT/AMMETER MODULE, P/N 32857. let refer to F-14-353.
This easy-to-install, plug-in module mounts in place of

the top blank cover plate of the upper-right front panel 2.4.4 TORCH NOZZLES
location in the 250 unit. This unique meter module
alternately displays welding voltage and current (of the A No. 8 Nozzle (1/2" I.D.), P/N 998893 to fit the MT-
dial-set welding condition) every 4-seconds. Two L.E.D.’s 200CC Torch, is included in the Migmaster 250 package.
labeled Amps and Volts provided below the meter win- This slip-on type nozzle includes a permanently mounted
dows, alternately illuminate to indicate which condition is insulator/spatter shield. The following standard duty slip-
being displayed. The voltage indication is displayed in 1/ on nozzles, also equipped with the insulator/spatter
10-volt increments (e.g.: 20.5), while the current indica- shield, are available:
tion is usually displayed in three-whole digits (e.g.: 225).
After the torch trigger is released, the meter will continue No. 6 Nozzle, Tapered (3/8" I.D.) ............ P/N 998895
to flash for 45-seconds the last condition used during No. 10 Nozzle (5/8" I.D.) ......................... P/N 998894
welding. At the end of this time, the meter will reset to No. 12S Spotweld Nozzle (3/4" I.D.) ......... P/N 17316
zero. For installation see Section 3.10.
Additionally, the following heavy-duty slip-on nozzles,
2.4.3 ST-23A SPOOL-ON-GUN TORCH, P/N 19164 also equipped with the insulator/spatter shield, are avail-
(see F-14-353). able:
The Migmaster 250 unit is equipped with a built-in control No. 8 Nozzle (1/2" I.D.) ........................... P/N 999471
for the ST-23A Spool-On-Gun welding torch. The ST- No. 10 Nozzle (5/8" I.D.) ......................... P/N 999472
23A is a high performance, 250 ampere continuous duty No. 12 Nozzle (3/4" I.D.) ......................... P/N 999473
spool-on-gun torch designed for the mig welding pro- No. 12 Spot Nozzle (3/4" I.D.) ................ P/N 999625
cess. It is completely portable (up to 30-ft.), air-cooled
and hand operated, and weighs less than three (3) 2.4.5 TORCH/WIRE FEED ACCESSORIES -- See
pounds which allows for great maneuverability and Tables 2.4.5.1 and 2.4.5.2.
operator convenience. The gun is equipped with two-
TABLE 2.4.5.1 Recommended MT-200cc Torch Accessories

Table 2.4.5.2 Guide Tubes/Feed Rolls
Wire Contact Tips Liners
Size & Type Short (S) Medium (M) Long (L) 10' 12' 15' Wire Guide Feed
Size & Type Tube Roll
Hard Wires & Cored Wires
.023" (.6mm) - 20543 999742 999743* - - Hard Wires - "V" Groove
.030" (.8mm) - 20544 996994 948850 17717 - .023" (.6mm) 21163 21155
.035" (.9mm) - 996995 996996 2075237 17718 2075238 .030" (.8mm) 21164 21155
.045" (1.2mm) 999578 996999 996998 2075237 17718 2075238 .035" (.9mm) 21165 . 21156
.052" (1.4mm) 948340 2075349 - 2075239 17719 2075240 .045" (1.2mm) 21165 21156
1/16" (1.6mm) 948341 996997 - 2075239 17719 2075240
Cored Wires - Serrated
Soft Wires (aluminum) .030" (.8mm) 21164 21160
.035" (.9mm) - 996995 996996 948862 - - .035" (.9mm) 21165 21160
3/64" (1.2mm) 999578 996999 996998 948863 - - .045" (1.2mm) 21165 21161
.052" (1.4mm) 21166 21161
(S) Short contact tips are recommended for proper wire stick out for flux cored wire welding. 1/16" (1.6mm) 21166 21161
(M) Medium contact tips are recommended for proper wire stick out in spray transfer Mig
welding. Soft Wires (aluminum) - "U" Groove
(L) Long contact tips are recommended for good visability and proper wire stick in dip transfer .035" (.9mm) 21167* 21158
Mig welding. 3/64" (1.2mm) 21168* 21158
* Requires support liner for .023" wire. Order P/N 999797.
* Requires support tube. Order P/N 21169

2.5 SAFETY
Before the equipment is put into operation, the safety

section at the front of this manual should be read
‡
completely. This will help avoid possible injury due to
misuse or improper welding applications.
32 ¼" Overall
The symbol which precedes safety notes appear-
ing throughout this manual means “Attention! Be Alert!
Your safety is involved.” The definitions relating to the
DANGER, WARNING and CAUTION safety notations
are described at the end of the Safety Section in the front
of this manual -- read them and their specific text
references carefully.
ˆ
III. INSTALLATION
3.1 LOCATION (Figure 3.1)
A proper installation site should be selected for the
ˆ
welding machine, if the unit is to provide dependable
40"
‡
service and remain relatively maintenance free. 191/2"
‡
ˆ
A proper installation site permits freedom of air move-
ment into and out of the welding machine, and also least
subjects the unit to dust, dirt, moisture, and corrosive Figure 3.1 Dimensional Drawing
vapors. A minimum of 18 inches (46 cm) unrestricted
space must be maintained between the welding ma- 3.2 ELECTRICAL INPUT CONNECTIONS
chine side and rear panels and the nearest obstruction.
The installation site should also permit easy removal of

the welding machine outer enclosure for maintenance
functions. It is recommended that a line disconnect switch be
installed in the input circuit to the welding machine.
This would provide a safe and convenient means to
completely remove all electrical power from the
CAUTION: Do not place any filtering device over the welding machine whenever it is necessary to perform
intake air passages of the welding ma- any internal function on the unit. (See Figure 3.2A.)
chine as this would restrict the volume of
intake air and thereby subject the welding
machine internal components to an over-
heating condition and subsequent failure.
Warranty is void if any type of filtering Before making electrical input connections to the
device is used. welding machine, “Machinery Lockout Procedures”
should be employed. If the connections are to be
If a forklift vehicle is used for lifting the unit, be sure that made from a line disconnect switch, the switch
the lift forks are long enough to extend completely under should be padlocked in the off position. If the con-
the base. nection is made from a fusebox, remove the fuses
from the box and padlock the cover in the closed
position. If locking facilities are not available, attach
a red tag to the line disconnect switch (or fuse box)
to warn others that the circuit is being worked on. If
Do not operate the machine without the running the plug-cap is used, (see 3.2B) remove plug from
gear installed. receptacle.

A. Input Electrical Requirements TABLE 3.1 Input Conductor and Fuse Size
Models of this welding machine are designed to be Recommended

operated from 208/230, or 208/230/380/400/460/575 Full Primary
volts single phase 50/60 Hz, depending on model. The Primary Load Input Ground
primary input voltage requirements are shown on the Input Line Fuse Conductor Conductor
welding machine nameplate. Volts Amperes Size Size Size
B. Input Conductor Connections 208 71 90 8 8

230 62 90 8 8
The input power cord on 208/230 Volts primary input 380 37 50 10 10
model is provided with an attachment plugcap. The 400 36 50 10 10
plugcap will mate with a 250 Volts, 50 Ampere receptacle 460 31 40 12 12
conforming to NEMA 6-50 R configuration. 575 25 30 12 12
The receptacle should be wired to a separately fused

disconnect or circuit breaker of the size listed in Table
3.1. This disconnect or breaker can be wired to a single
phase system or to two conductors of a three phase
system. A third conductor for grounding should also be Only qualified personnel should make these
connected between the disconnect and the receptacle. changes. Make certain the primary power has been
discoonnected and all safety procedures have been
Figure 3.2A illustrates wiring to a single phase system followed before proceeding with these instructions.
and Figure 3.2B illustrates wiring to a three phase
system. Fig. 3.3A shows the 230v and 208v connections for the
208/230 dual voltage model. Change over is made by
The 208/230/380/400/460/575 primary input voltage unit removing the right side panel below the wire feed com-
is provided with a three conductor primary input cable partment and switching the primary transformer tap at
without plugcap. The ground lead of this cable should be the top of the power switch with the unused alternate
connected to a reliable ground and the two remaining voltage tap located next to the main transformer (see
wires should be connected to the separately fused lines Fig. 3.3B). Both voltage taps (the one currently con-
of the disconnect or breaker as shown in Figures 3.2C nected to the switch and the unused alternate voltage)
and 3.2D. are marked with the input voltage requirement. All units
are supplied from the factory connected for the highest
All machines leave the factory with their primary electri- voltage (230 vac). Before switching the voltage taps,
cal input requirements internally-connected for the high- verify the actual voltage requirement as well as the
est voltage rating available in each model (e.g.: 230-volt current voltage connection to be certain re-connection is
for the 208/230-volt units; and 575-volt for the "multi- necessary. If voltage tap re-connection is necessary, the
voltage" units). following paragraphs cover the procedure to switch the
voltage tap for either 208vac or 230vac input.
208/230 MODEL ONLY (With Plug-Cap) 208/230/380/400/460/575-V. MODELS
SINGLE-PHASE THREE-PHASE SINGLE-PHASE THREE-PHASE

Fused
GRD GRD GRD GRD
Line
Disconnect
Switch,
or
Circuit Breaker
GREEN GREEN
Wall Receptacle CONDUCTOR
(GROUND)
MIGMASTER
SYSTEM
CONNECTS HERE
Figure 3.2 A Figure 3.2 B Figure 3.2 C Figure 3.2 D
Figure 3.2 - Primary Connection
10

When changing the input voltage connections, the
unused lead must be insulated and positioned to
prevent contact with any other internal components
of the machine or the machine side panel. The clear-
ance between the unused lead and other compo-
nents must be at least one inch (see Fig. 3.3B for
illustration of the proper position). FAILURE TO
INSULATE AND POSITION THIS LEAD PROPERLY
WILL CAUSE A SERIOUS SHOCK HAZARD.
Figure 3.3A - Primary Reconnections at Switch

For 208/230 Volt Models
The terminal labeled GRD is connected to the weld-

ing machine chassis and is for ground purposes
only. It must be connected to a good electrical
ground. Do not connect a conductor from the termi-
nal labeled GRD to any one of the L1, L2 terminals as Fig. 3.3B - Position of Alternate Voltage Tap
this will result in an electrically hot welding machine
chassis.
C CONNECTING FOR 208 VAC INPUT
After the panel is removed, locate the 208 Vac lead (Fig.
3.3B) and cut the tie-wrap to remove the insulation
sleeving (on early models this lead may have been
wrapped with black electrical tape). Open the insulating
cover around the power switch (Fig. 3.3C.) to expose the
terminals and disconnect the 230 Vac lead from the top
of the switch as shown in Fig. 3.3A. Insulate the 230 Vac
lead that was removed from the power switch with
sleeving or approved electrical tape and re-position to a
safe area beside the transformer (see Fig. 3.3B), leaving
a minimum of one inch clearance from other compo-
nents and the side panel.
D CONNECTING FOR 230 VAC INPUT
After the panel is removed, locate the 230 Vac lead (Fig. Fig. 3.3C - Power Switch Connection
3.3B) and cut the tie-wrap to remove the insulation
sleeving (on early models this lead may have been
11

wrapped with black electrical tape). Open the insulating E. Reconnecting from 575 VAC Input
cover around the power switch (Fig. 3.3C.) to expose the
terminals and disconnect the 208 Vac lead from the top Figure 3.3.1 shows you how to reconnect the "multi-
of the switch as shown in Fig. 3.3A. Insulate the 208 Vac voltage" model from a 575-volt input to any of the
lead that was removed from the power switch with remaining available voltage inputs 200 or 380 or 400 or
sleeving or approved electrical tape and re-position to a 460-volts. These connections are made by unscrewing
safe area beside the transformer (see Fig. 3.3B), leaving the right side panel below the wire feeding compartment,
a minimum of one inch clearance from other components and locating the primary voltage changeover terminal
and the side panel. board handing in the center of the lower compartment.
This board contains copper links which must be recon-
Connect the proper voltage (208 Vac or 230 Vac) tap to nected to match the silk-screened voltage designations
the power switch and tighten securely. Check all other for the input you plan to use (it comes factory-connected
leads connected to the power switch for tightness and for a 575-volt input), see Figure 3.3.1.
clearance from internal components before securing the
insulating cover around the power switch. Replace the 3.3 SECONDARY OUTPUT CONNECTIONS
side panel.
The Migmaster 250 Welding System is completely self-
contained so that the front panel torch fittings (Euro-type
MT and Spool gun) are internally connected to the
welding polarity (D.C. Reverse or D.C. Straight) via the
secondary output terminals located inside the wire feed-
ing compartment (see Fig. 4.1). The machine comes set
up for D.C.R.P. welding as described in Section 4.1.3.
3.4 TORCH CONNECTIONS
The torch (MT-200cc), which is supplied as standard

equipment with the Migmaster 250 System, is provided
with a euro-type adapter which directly connects to the
torch fitting mounted on the front panel. Line up matching
holes, push on and tighten locking collar. As shipped
from the factory, the euro or common connector type
torches are set-up for D.C.R.P. welding polarity (see
sections 3.3 or 4.1.3). To connect the spool-on-gun torch
(ST-23A) see Section 4.2.2.
3.5 WIRE FEEDER MECHANISM

PRIMARY VOLTAGE CONNECTION CHART
VOLTAGE CONNECTION NO. OF STRIPS 3.5.1 DRIVE ROLLS

1-2 1
208 6-7 1
The drive roll has two grooves: the small groove feeds
7-8 FLEX
0.035 in. diameter wire, the large groove feeds 0.045 in.
1-2 1
wire. The groove nearest the gear motor feeds the wire.
230 6-7 1
If the required groove is not in that position:
5-8 FLEX
380 3-7 2
4-8 FLEX
A. Release the pressure drive roll lever and lift the
400 2-6 2 assembly upward.
7-8 FLEX
460 2-6 2 B. Remove the two (2) screws holding the drive roll to
4-8 FLEX the gear.
575 2-3 2
4-8 FLEX C. Reverse the drive roll on the drive roll shaft.
Figure 3.3.1-Primary Reconnections at Voltage D. Replace the screws and tighten.

Changeover Terminal Board for 208/230/380/400/460/
575Volt Models E. Secure the pressure drive roll assembly.
12

3.5.2 WELDING WIRE SPOOL 3.5.4 BRAKE DRAG ADJUSTMENT
Brake disc friction should provide enough drag to keep
the wire spool or core from spinning freely after wire feed
stops. If adjustment is required, turn adjusting screw
As with any work area, make sure safety glasses clockwise to increase drag, counterclockwise to de-
with side shields are worn when handling or chang- crease it. Drag should be just low enough to limit wire
ing wire or clipping wire off at the spool or at the end overrun.
of the torch. Hold onto the wire coming off the spool
with one hand before clipping. Serious eye injury 3.6 CONNECTION OF SHIELDING GAS SUPPLY
can result due to the springiness of the wire which The R-33-FM-580 Regulator-Flowmeter is designed for
can quickly unravel, or a cut wire end which may use with an argon or argon-mix cylinder of shielding gas.
shoot across the room. It is adjustable for delivering up to 50 cfh through the
Install a spool of welding wire on the hub as follows: torch. To set up the system do the following:
A. Unscrew spool nut from hub.

B. Place wire spool on hub to rotate clockwise as wire
is unwound; hub pin must engage hole in spool. Do Not adapt R-33-FM-580 for use with CO2. Relief
C. Replace nut. device may rupture if CO2 is used with the R-33-FM-
580.
3.5.3 THREADING WELDING WIRE
a. With the cylinder cap in place CAREFULLY slide
A. Turn off power switch. the cylinder of gas onto the Migmaster 250 cylinder
rack.
b. Secure the cylinder to the unit, using the chain
provided.
c. Unscrew the cylinder cap.
When the power switch is on, and gun trigger is d. Open the cylinder valve slightly, just for an instant,
depressed, the electrode wire becomes electrically to blow away any dirt or dust which may have ac-
hot, and the wire feed rolls are activated. cumulated in the cylinder valve outlet. Be sure to
keep your face away from the valve outlet
B. Release pressure drive roll assembly and lift up to protect your eyes.
ward. Check that proper wire diameter groove is in e. Attach the regulator to the cylinder valve, tighten
the inner position. the union nut securely with a 1-1/8in. open end or
an adjustable wrench.
CAUTION: Before threading welding wire through cas-
ing, make sure chisel point and burrs have
been removed from wire end to prevent wire
from jamming in gun casing or liner.
C. Feed the wire from the spool through the inlet CYLINDER
VALVE
guide, across the drive roll groove and into gun CYLINDER
outlet guide. PRESSURE
GAUGE
Make sure that the proper “outlet guide tube” is inserted

into the front-panel gun fitting for the size and type of wire OUTLET
being used, see Table 2.4.5.2 for wire feed accessories CONNECTION
(Section 2.4.5).
To insure proper wire feeding, it is important that the wire Fig. 3.6 R-33-FM-580 Regulator
be kept clean and that the drive rolls be periodically
cleaned of any chips or scale that might be carried into f. Attach the gas hose from the rear of the Migmaster
the gun liner and cause sticking. 250 to the regulator outlet connection (see Fig. 3.6).
D. Lower pressure roll assembly and secure. Check g. Slowly open the cylinder valve a fraction of a turn.
that the gears mesh. Feed wire through to gun tip When the regulator pressure gauge pointer stops
with gun trigger (power ON). moving, open the cylinder valve fully.
13

Welding cables should be kept as short as possible and
be of adequate current carrying capacity. Resistance of
Never stand directly in front of or behind the regula- the welding cables and connections causes a voltage
tor when opening the cylinder valve. Always stand drop which is added to the voltage drop of the arc.
to one side. Excessive cable resistance may result in a reduction of
the maximum usable current output of the equipment.
h. Using a leak test solution, such as P/N 998771 (8
oz. container) or soapy water, test for leakage The proper operation of this equipment is to a large
about the cylinder valve stem, the regulator inlet extent dependent on the use of welding cables and
connection, and the hose connections at the regu- connections which are in good condition and of adequate
lator and at the Migmaster 250 for leakage. Correct size.
any leaks before starting work.
3.8 ASSEMBLE REAR WHEELS
i. If work is to be stopped for a half-hour or more, or
the regulator is to be removed from the cylinder, The unit's running board is factory assembled except for
shut down the regulator as follows: the rear wheels which are packed loose in the shipping
carton. The rear gear consists of 2-wheels, 4-washers,
a. Close the cylinder valve. 2-cotter pins, and an axle. To install the gear, do the
following:
b. Release gas from the regulator by closing the
torch trigger lever. a. Insert the axle through the holes provided at the
rear of the gear.
c. When pressure gauge drops to zero, the regu-
lator is de-pressurized and shutdown. b. Place a washer onto each end of the axle, then slip
on the wheels, then add another washer to the
j. Each regulator is equipped with a porous metal outside of each wheel, and secure the whole as-
inlet filter, P/N 71lZ33, pressed into the regulator sembly by inserting a pin in each end of the axle.
inlet nipple. No. regulator should be connected to
a cylinder or station valve unless it contains this c. Remove the existing shipping supports by un-
filter. You can replace the filter if you have reason screwing from chassis.
to do so. To remove a filter refer to the regulator
instruction literature for details. 3.9 INSTALLING OPTIONAL SPOT/STITCH/ANTI-
STICK MODULE
k. Regulators in need of repair should be returned to
your Welding Equipment distributor or to an autho- a. Remove lower blank-cover plate from upper-right
rized Remanufacturing Center. front panel of power supply -- save the four mount-
ing screws.
b. Locate the harness-connected 15-pin plastic plug,

P3, inside the mounting cavity. Note that this plug
If welding is performed in a confined area, shielding
will have a jumper plug with jumper wires con-
gas leaks could result in a buildup of shielding gas
nected to it -- remove (and save) the jumper plug.
concentration, displacing oxygen, thereby endan-
(The jumper plug must be reinstalled if the module
gering personnel enter the area.
is ever removed.
3.7 Connect the work clamp solidly to the workpiece or
c. Connect the 15-pin plug into the matching recep-
work table. Clamp onto a bare metal area.
tacle on the rear of the optional control module. The
plug will only fit one way.
d. Install the control module in place of the blank

A good electrical connection to the work is essential panel removed in Step a., using the same four
to proper welding operation and to prevent electric screws that you saved.
shock.
3.10 INSTALLING OPTIONAL DIGITAL METER
a. Remove the top blank-cover plate from the upper-

right front panel of the power supply -- save the four
mounting screws.
14

b. Locate the harness-connected 10-pin plastic plug, A. Gun trigger circuit 24 volts AC.
PL1, inside the mounting cavity. This plug does
not have a jumper plug connected to it. Wire feeder circuit 24 volts DC.
c. Connect the 10-pin plug into the matching recep- B. Main welding secondary circuit. Depending upon
tacle on the rear of the optional meter module. the tap switch position, various secondary volt-
ages can be obtained. Then rectified, open circuit
d. Install the meter module in place of the blank- voltages can be selected between 18 and 56 volts
panel removed in Step a., using the same four DC when the secondary contactor is energized.
screws that you saved.
4.1.2 VOLTAGE CONTROL (Coarse Range Selector
and Fine Adjustment Range Selector)
IV. OPERATION
Voltage control is by means of two high current tap
switches which connect the rectifier bridge to various
4.1 CONTROLS (See Figure 4.1)
secondary taps.
4.1.1 POWER SWITCH
The COARSE VOLTAGE RANGE Selector is a three-
position switch, LOW/MED/HIGH, by which the operator
A line toggle switch on the front panel energizes the
selects the approximate range of voltage (or heat, that
primary of the main transformer. This switch also turns on
determines the arc length) to be applied to the weld. It is
the fan, which is connected across a portion of the
a coarse selection control and is used in conjunction with
primary winding.
the Fine Voltage Adjustment selector following. It must
not be switched under load.
Two transformer secondary windings also become ener-
gized:
4.2.3
4.1.5 4.2.2 Secondary Output Terminals
2.4.2 for Welding Polarity Change-
over, see 4.1.3.
10A. Fuse 4.1.6
4.1.2 4.1.3 Torch

Cable
Work
Cable
4.1.1
15

The FINE VOLTAGE ADJUSTMENT Selector is an 4.1.5 WIRE FEED SPEED CONTROL
eight-position switch by which the operator selects the
exact amount of arc voltage (or heat) to be applied to the Wire feed speed is controlled by the wire speed potenti-
weld (within the coarse range selected above). This ometer knob on the front panel. The solid state control
allows you to fine-tune the voltage required; the higher allows for infinitely variable speeds up to 650 IPM.
the number selected (1-8), the hotter the weld. The Fine
Voltage Selector switch also has an "open" detent at the This wire speed pot is used to set the speed at which the
six o'clock position. Placing the switch in this position welding wire is fed out from the torch and hence the
allows operation of the torch trigger to feed electrode welding amperage. The panel-face numbers on the dial
wire without the wire being electircally "hot". This switch (0-10) are used for reference and do not directly indicate
also, must not be switched under load. wire feed speed; the higher the number, the faster the
speed.
CAUTION: These tap switches carry several hundred 4.1.6 STD./SPOOL GUN SELECTOR
amperes, and must not be switched under
load, as this will cause the contacts of the This two-position toggle switch is located inside the unit
switches to arc. on the mid-wall of the wire feeding compartment and is
labeled Standard and Spool Gun. It is used to select
4.1.3 SECONDARY WELDING CONNECTIONS standard metal inert gas welding (MIG) with the MT-
200CC, or welding with the ST-23A (spool-on-gun) torch.
The secondary contactor, with parallel poles, is used to
make and break the circuit between the transformer 4.2 PROCESS SETUP
secondary and the rectifier. This contactor is turned on
and off when the torch trigger (in the 24 volt circuit) is 4.2.1 STANDARD MIG SEAM WELDING W/MT-200CC
operated.
Refer to Sections 4.3.1, 4.3.2, 4.3.3, 4.3.4, and Table
The secondary output welding terminals, POS.(+) and 4.3.3.
NEG(-), are located in the right side wire feeding com-
partment and are used to set the welding polarity 4.2.2 ST-23A SPOOL-ON-GUN CONTROL CONNEC-
(D.C.R.P. or D.C.S.P.) in which the machine will operate TION/OPERATION
(see Fig. 4.1). As shipped from the factory, the 250 is set
up to operate in D.C.R.P. (TORCH fitting is connected The Migmaster 250 is equipped with a built-in control for
to Positive, and WORK cable/clamp is connected to the Spool Gun which operates via the amphenol control
Negative output). To weld using D.C.S.P., simply mount receptacle and a screw adaptor that provides Gas and
the WORK cable to the Positive output and the TORCH Power. The ST-23A Torch (see Section 2.4.3) has a
fitting cable to the Negative output terminal. amphenol-plug control cable connection, and a gas/
power cable, see Figure 4.2.2.
4.1.4 CONTACTOR CONTROL
To operate the unit with the ST-23A Torch connected, do
Refer to the schematic diagrams. Note that the coil of the following (refer to Fig. 4.2.2):
the 24 volt contactor is activated with the torch trigger
and is energized when the trigger is pulled. The gas A. Place the STD./Spool Gun selector toggle switch
solenoid is in parallel with the contactor coil and is (4.1.6) in the 250 to its Spool Gun position.
energized at the same time.
B. Connect the ST-23A control cable amphenol to the
When the trigger switch is released, the contactor drops receptacle labeled CONTROL on the 250s front
out and disconnects the load. panel.
C. Remove the threaded plastic plug from the Gas/

Power adaptor (on the 250's front panel) using a
Because of the charged capacitor bank in the sec- clockwise rotation. Connect the ST-23A gas/power
ondary circuit, the output voltage will take a few cable to the panel adaptor using a counter-
seconds before falling to zero volts. clockwise rotation. As shipped from the factory,
the 250's secondary output power terminals are
The gas valve shuts off when the contactor opens. set-up for D.C.R.P. welding polarity (see Section
4.1.3). IMPORTANT -- Always make sure that
the plastic plug is screwed back into the adaptor
when the ST-23A gas/power cable is discon-
nected, because hielding gas will escape from the
adaptor unless the gas cylinder is shut-off.
16

Figure 4.2.2 - Connecting Spool-On-Gun to Services
D. Connect the 250s WORK cable to the workpiece. weld from the time the torch trigger is released until the
main contactor is deenergized. This delay allows the
E. Set Migmaster 250 voltage tap switches to welding wire to burn back, away from the work, so it
RANGE and FINE ADJUSTMENT VOLTAGE set- wont stick in the weld puddle.
tings desired.
This delay time, controlled by the anti-stick potentiom-
F. Turn on the Migmaster 250s power switch and eter, is variable from approximately 0.05 seconds to 0.5
begin seam mig welding. seconds. The required delay time generally depends on
the WIRE SPEED Adjustment setting on the front panel
If the optional Spot/Stitch/Anti-Stick control module is - the higher the setting, the faster wire will feed into the
installed, the ST-23A gun may be operated using these weld, and the more delay time will be required.
optional features, see Section 4.2.3.
If, when using the Anti-Stick feature, the welding wire
4.2.3 OPTIONAL SPOT/STITCH/ANTI-STICK CON- tends to stick in the puddle at the end of a weld, the Anti-
TROL MODULE Stick time should be increased; if, on the other hand, the
wire burns back into the torch tip, the anti-stick time
This optional control module allows the operator to use should be decreased. Setting the anti-stick time to Min
the 250 for Spot or Stitch or Continuous welding opera- effectively cancels the anti-stick feature.
tions. It also includes an adjustable Anti-Stick feature to
select various burnback times to prevent wire from This Anti-Stick feature is available for all three welding
sticking in the puddle after a weld. modes - Continuous, Spot, and Stitch.
The module consists of three pots (one for Spot-Stitch 4.2.3.2 CONTINUOUS WELDING MODE OPERATION
Weld Time "ON", one for Stitch Weld Time "OFF", and
one for Anti-Stick Time modes) and one three-position A. Place the three-position toggle switch in Continu-
toggle switch to select the welding operation desired ous weld mode (center position) for mig seam
(Spot, Continuous or Stitch). For installation, see Section welding.
3.9; for operation, see following:
B. Set the Anti-Stick Time as required (see 4.2.3.1).
4.2.3.1 ANTI-STICK WELDING OPERATION
Anti-Stick feature provides a time delay at the end of a
17

C. Set the coarse and fine Voltage control B. Be sure a standard nozzle (and not a spot weld
switches and wire speed pot to the desired settings nozzle) is installed on the torch.
and begin welding operation as described in Sec-
tions 4.3.2 and 4.3.3. C. Set the length of time the arc will be ON for each
sequence by adjusting the Spot-Stitch Weld Time
4.2.3.3 SPOT WELDING MODE OPERATION control on the power supplys front panel. This
timer has an approximate range of from 0.4 sec-
A. Place the three-position toggle switch in Spot onds at the minimum setting to 3.5 seconds at the
position. maximum setting. Set the length of time the arc will
be OFF for each sequence by adjusting the Stitch
B. Replace the standard nozzle with the No. 12 Spot Weld Time control on the front panel. This timer
weld Nozzle P/N 999625. has an approximate range of from 0.4 seconds at
the minimum setting to 3.5 seconds at the maxi-
C. Trim the welding wire back so the end is slightly mum setting.
inside the nozzle.
D. Set the coarse and fine voltage control switches
D. Set the coarse and fine voltage control switch- and wire speed as specified in Table 4.3 under
es, wire speed, and the Spot-Stitch Weld Time see Continuous Weld Conditions for:
Table 4.3, for the thickness of the metal being
welded and the diameter of the weld wire being i. The type weld being made (see diagrams to the
used. left of each column of figures).
E. To spotweld: ii. The thickness of the metal being welded.
i. Press the torch nozzle squarely on the top plate. iii. The gap (if any) between the pieces being weld-
Apply enough pressure to hold the two pieces of ed.
metal firmly together, so there is no loose play
between them. iv. The diameter of the welding wire being used.
E. When using the Stitch weld mode, before starting

the weld the welding wire should extend about
1/ 2-in. beyond the end of the nozzle. Adjust this
length by either clipping off the end of the wire with
insulated cutters or by using the torch switch.
Fig. 4.2.3 - Cross Section of Good Spotweld

Power supply contactor becomes energized the mo-
ii. Pull the trigger, holding the gun motionless and ment the torch trigger is depressed. Arcing can
firmly. The electrode wire and shielding gas will occur if the wire is brought to a ground. Keep the
be fed to the work, and the arc will be maintain- torch always from ground until welding is to begin.
ed for the length of time set in Step D. above.
F. During the welding, use the same welding techni-
iii. After the preset time has elapsed, the wire will ques as described in Section 4.3.3 and 4.3.4.
stop feeding, the arc will be broken, and the
shielding gas will stop flowing.
4.2.5 DUTY CYCLE (Figure 4.2.5)
A good spotweld will penetrate through both lay-
ers of metal, and will have a small nugget on the The duty cycle of the equipment is the percentage of a 10
reverse side, (Fig. 4.2.3) minute period which it can operate safely at a given output
current. The Migmaster system is rated at 50% duty
4.2.4 STITCH WELDING MODE OPERATION cycle. This means that the equipment can be safely
operated at 250 amperes for five minutes out of every 10.
A. Place the three-position toggle switch in Stitch This cycle can be repeated indefinitely (See Figure
position. The stitch weld mode uses a series of pre- 4.2.5).
timed arc-on/arc-off time sequences to allow cooler
welding.
18

4.3 OPERATING PROCEDURES
4.3.1 OPERATING SAFETY PRECAUTIONS
Comply with all ventilation, fire and other safety require-

ments for arc welding as established in the SAFETY
Section at the front of this manual.
Also remember the following:
A. Because of the radiant energy of the welding arc

and the possibility of drawing an arc before the
helmet is lowered over the face, the operator
should wear flash goggles with filter lenses under
his helmet. The helmet filter plated should be
Fig. 4.2.5 Duty Cycle Curves shade number 11 (nonferrous) or 12 (ferrous). All
those viewing the arc should use helmets with filter
plates, as well as flash goggles. Nearby personnel
should wear flash goggles.
4.2.6 VOLT/AMPERE CURVES (Figure 4.2.6)
B. The radiant energy of the arc can decompose
The Volt/Ampere curves show the output Voltage avail-
chlorinated solvent vapors, such as trichloroethy-
able at any given output current for the various Voltage
lene and perchlorethylene, to form phosgene,
Selector positions in each range low, medium, and high.
even when these vapors are present in low con-
centrations. DO NOT weld where chlorinated sol-
The actual operating point of load Voltage and Current
vents are present in atmospheres in or around the
is determined by type of process, electrode, shield gas,
arc.
wire feed speed, and operating technique.
C. DO NOT touch the electrode, nozzle or metal parts
in contact with them when power in ON: all are
electrically energized (HOT) and can cause a
possibly fatal shock. DO NOT allow electrode
to touch grounded metal: it will create an arc flash
that can injure eyes. It may also start a fire or
cause other damage.
D. When working in a confined space, be sure it is

safe to enter. The confined space should be tested
for adequate oxygen (at least 19%) with an approv-
ed oxygen measuring instrument. The confined
space should not contain toxic concentrations of
fumes or gases. If this cannot be determined, the
operator should wear an approved air supplied
breathing apparatus.
Avoid gas leaks in a confined space, as the leaked gas

can dangerously reduce oxygen concentration in the
breathing air.
DO NOT bring gas cylinders into confined spaces.
When leaving a confined space, shut OFF gas supply at

the source to prevent gas from leaking into the space, if
the switch is accidently kept depressed. Check the
breathing atmosphere in the confined space to be sure
it is safe to reenter.
Figure 4.2.6 VOLT/AMPERE CURVES
19

E. Never operate the equipment at currents greater b. Attempting to weld over grease or oil can cause
than the rated ampere capacity; overheating will weld defects.
occur.
c. Before welding on aluminum, be sure to clean
F. Never operate equipment in a damp or wet area surface thoroughly using a stainless steel brush.
without suitable insulation for protection against
shock. Keep hands, feet and clothing dry at all 4.3.3 SET-UP PROCEDURE
times.
A. Determine the material type, thickness and joint
G. Whenever the equipment is left unattended, turn configuration to be welded from Table 4.3 and use
all control and power supply switches and gas the recommendations to set the following:
supplies OFF and open the main line switch.
a. Coarse Voltage Range, LOW/MED/HIGH.
H. Wear dark substantial clothing to protect exposed
skin from arcburn, sparks and flying hot metal. b. Fine Arc Voltage Setting, 1 thru 8 (the higher the
number, the hotter the weld).
I. Turn off welding power before adjusting or replac-
ing electrodes. c. Wire Speed setting, 0 thru 10 (the higher the
number, the faster the speed).
B. Set the two-position switch in the wire feeder com-

Never operate the welding machine with any por- partment to STANDARD for seam welding with the
tion of the outer enclosure removed. In addition to MT-200CC torch. (For ST-23A Spool-On-Gun
a hazard, improper cooling may result in damage to welding, see Section 4.2.2).
the welding transformer and the welding machine
components. Warranty is void if the machine is C. If optional Spot/Stitch/Anti-Stick Control module is
operated with any portion of the outer enclosure installed, refer to Section 4.2.3 for operation, set-
removed. tings and welding condition table.
4.3.2 PRE-WELD REQUIREMENTS D. Make sure the MT-200CC torch fitting and the
Work cable are connected to the proper output
Before welding commences, with all power OFF, check terminals (inside unit) for the polarity desired.
the following:
A. All safety requirements have been read and un-

der stood. Only qualified personnel should make these changes.
Make certain the primary power has been discon-
B. All hoses and cables are in good condition, safely
nected and all safety procedures have been fol-
insulated and securely connected.
lowed before proceeding with these instructions.
C. Turn on gas supply by slowly opening cylinder
valve to full ON. Normally, you will set-up for reverse polarity; this
means the torch fitting is connected to the POS (+)
D. Correct size wire accessories have been installed output terminal and the Work cable to the NEG
on the wire feeder, drive gears are meshed, wire (-) output terminal.
pressure set, and guide tube is installed for type
and size wire you plan to use, refer to Tables For straight polarity, do just the opposite; torch
2.4.5, and 4.3.. fitting to NEG (-) output terminal and Work cable
E. Spool of correct size wire is locked in place, brake to POS (+) output terminal.
tension is set, and wire is properly threaded
through the inlet guide to the gun tip. 4.3.4 WELDING OPERATION
F. The wire feeding compartment cover is closed A. Turn Power switch (on unit) to ON position -- be
and secure. careful not to operate the torch switch.
G.Make sure that the metal to be welded is properly B. Before starting the weld, the welding wire should
prepared: extend about 1/2-inch beyond the end of the nozzle.
Adjust this length by either clipping off the end of the
a. Remove loose surface rust, scale or paint with wire with insulated cutters or by using the torch
wire brush or sander. switch.
20

up or down, it is very important to keep the arc on the
leading edge of the puddle to ensure complete pene-
Power supply contactor becomes energized the mo- tration.
ment the torch trigger is depressed. Arcing can
occur if the wire is brought to a ground. Keep the G. Some welders who are accustomed to welding with
torch away from ground until welding is to begin. stick electrodes may tend to push the torch into the
weld. This is neither necessary nor desirable, since
C. To start the weld, hold the torch so the welding wire is the wire electrode is being mechanically fed into the
approximately 1/4-in. from the work, then press the weld.
torch trigger.
Please note that the Wire Speed control can be
D. The welding wire should be pointed into the joint at adjusted for the gauge of metal to be welded. How-
angles of approximately 450 for fillet welds, and ever, the Coarse Voltage Range and Fine Voltage
approxmately 900 for butt welds, (Fig 4.3.4.1). setting must not be switched while welding.
E. The torch angle relative to the length of the weld should H. To stop the weld, release the trigger and pull the torch
be approximately 100 from the vertical (Fig. 4.3.4.2). from the work. When leaving equipment unattended,
always shut OFF and disconnect all input power and
F. When welding in the vertical position, traveling either shut off shielding gas at source.
TABLE 4.3, Continuous/Stitch Weld Conditions
Fig. 4.3.4.1 - Angle of Welding Wire with Joint

21

MIG PROCESS SELECTION GUIDE
MIG PROCESS SELECTION GUIDE
SETTING TO SET MACHINE
SHOWN AS:
1. Find the thickness of the base plate to be welded.
Arc
Voltage 2. Find the diameter of the filler wire to be used.
Voltage Range 3. Find the suggested arc voltage, range and wire feed setting by following
the wire diameter row across (to the right) and the plate thicknesses
Wire Feed
Speed column down.
4. Set the arc voltage selector switch, voltage range switch and the wire
feed pot to the settings indicated.
CARBON STEEL BASE PLATE THICKNESS
WIRE
24 GA. 20 GA. 18 GA. 16 GA. 3/32" 1/8" 3/16" 1/4" 3/32" 1/8" 3/16" 1/4"
DIAMETER
SHORT CIRCUITING ARC SPRAY ARC
1 2 3 4 6 1 4
.023" LOW LOW LOW LOW LOW MED MED
1.2 1.3 2.5 3 4.3 6.5 10
4 4 7 7 8 2 5 6 7 4
.030" LOW LOW LOW LOW LOW MED MED MED MED HIGH
3 3.5 4 4.5 5 5.5 6 6.5 6.8 8.5
3 4 6 6 1 2 5 5 6 6
.035" LOW LOW LOW LOW MED MED MED MED MED MED
1.8 2 3 3.8 4 4.5 5.5 5.5 6 6
4 5 6 6 3 8 8 2 2
.045" LOW LOW LOW LOW MED MED MED HIGH HIGH
1.8 2 2 2.8 3 4 4 4.2 4.2
Settings were developed using 75% argon - 25% carbon dioxide shielding gas.
For 100% carbon dioxide shielding gas, add 2 to the arc voltage setting shown above.
Settings were developed using 98% argon - 2% oxygen shielding gas.
TABLE 4.3, Continuous /Stitch Weld Contitions
This equipment is provided with a thermostat (OL) in the 5.2 INSPECTION AND SERVICE
transformer (T1) windings which will open and prevent
the contactor (CON) from closing if the transformer Keep Equipment in clean and safe operating condition
windings are overheated. If the thermostat opens, allow free of oil, grease, and (in electrical parts) liquid and
the equipment to idle with fan running for approximately metallic particles which can cause short-circuits.
15-min. before attempting to weld again.
Regularly check cylinder valves, regulators, hoses, and
V. SERVICE gas connections for leaks with soap solution.
5.1 MAINTENANCE Check for and tighten loose hardware including electrical
connection. Loose power connections overheat during
welding.
Immediately replace all worn or damaged power cables

Be sure the branch circuit or main disconnect switch
and connectors. Check for frayed and cracked insulation,
is off or electrical input circuit fuses are removed
particularly in areas where conductors enter Equipment.
before attempting any inspection or work on the
inside of the welding machine. Placing the power
The electrode wire and all metal parts in contact with it are
switch on the welding machine in the OFF position
electrically energized while welding. Inspect these parts
does not remove all power from inside of the equip-
periodically for defective insulation and other electrical
ment.
hazards.
Inspection, troubleshooting and repair of this equip-

If uninsulated cable and parts are not replaced, an
ment may ordinarily be undertaken by a competent
arc caused by a bared cable or part touching a
individual having at least general experience in the
grounded surface may damage unprotected eyes or
maintenance and repair of semi-conductor elec-
start a fire. Body contact with a bared cable, connec-
tronic equipment. Maintenance or repair should not
tor, or uncovered conductor can shock, possible
be undertaken by anyone not having such qualifications.
fatally.
Shut OFF shielding gas supply at source.
Keep power cables dry, free of oil and grease, and
protected at all times from damage by hot metal and
To aid in checking and servicing, use Schematic, Figure
sparks.
5.1.
22

Clean dirt and metal particles from drive roll groove feeder compartment. Failure of this fuse will shut off the
weekly; replace roll if badly worn. contactor, shielding gas and wire feeder.
5.2.1 POWER SOURCE
5.2.1.1 RECTIFIER If it should become necessary to replace this or any

other fuse in the welding machine, ensure that the
It is recommended that the rectifier be cleaned occasion- proper size fuse is used as a replacement.
ally by blowing it out with compressed air. This cleaning
operation is necessary so that maximum cooling will be 5.2.1.5 OVER-TEMPERATURE PROTECTION
accomplished by the air stream. This should be done
periodically, depending upon the location of the unit and The machine is equipment with a thermostat. On contin-
the amount of dust and dirt in the atmosphere. ued high current application, if the thermostat reaches an
abnormally high temperature, it will deenergize the
The hermetically sealed silicon diode rectifiers are spe- contactor. This thermostat will reset itself automatically
cially designed for welding machine use and will not age after the transformer windings have cooled to a safe
or deteriorate in use. The four diodes are mounted on level. While deenergized, neither the contactor, shield-
heat sinks. A periodic cleaning of dust and dirt from these ing gas nor wire feeder can be operated.
is necessary to insure cooling of the rectifiers. Access is
by removal of top cover and side panels. Should any 5.2.2 WIRE FEEDER
diode accidentally be damaged and need replacement, it
can be quickly removed from the heat sink. The replace- When soft wire is fed, the drive rolls may pick up metal
ment diode should be of the same type as the one from the wire surface. Accumulation on the rolls may
removed, and should be locked securely to the sink, score the wire with resulting unwanted friction and im-
preferably with a torque wrench set for maximum of 25 ft. proper feeding.
lbs. and a minimum of 20 ft. lbs. Excessive torque will
distort the mechanical structure and may break the Inspect the rolls regularly and clean them with a fine-wire
hermetic seal, whereas too little torque will result in power brush. Avoid roughening, or removing the hard-
improper electrical connections. ness of groove surfaces in grooved rolls. Any roughening
may score the wire, just as the accumulation being
NOTE: Thermal conductive compound (Wakefield En- removed may do.
gineering #120 Thermal Compound or equiva-
lent) must be reapplied to heat sink-diode mat- 5.3 TROUBLESHOOTING
ing surface whenever a diode is replaced.
If welding equipment doesnt work right despite compli-
5.2.1.2 FAN MOTOR ance with checklist inspect as follows:
All models are equipped with an exhaust fan and rely on A. With all power controls ON and other operating
forced draft for adequate cooling for high duty cycles and controls at required settings, visually check all
overloads. Lubricate the fan motor with a few drops of power cables and connections for evidence of
SAE-20 non-detergent oil every three months. overheating or sparking.
5.2.1.3 TRANSFORMER
Occasional blowing out of the dust and dirt from around

To avoid shock, do NOT touch electrode wire or
the transformer is recommended. This should be done
parts in contact with it, or uninsulated cable or
periodically depending upon the location of the unit and
the amount of dust and dirt in the atmosphere. The connections.
welding machine case cover should be removed and a
clean, dry air stream should be used for this cleaning B. Check all gas (and water) hoses and connections,
operation. flowmeters, and regulators for possible sources of
leakage, breakdown or intermittent failure.
5.2.1.4 24 VOLTS WIRE FEEDER AND CONTROL
CIRCUITS C. Isolate trouble to one part of the welding installa-
tion: primary power supply, power source, Feeder
The 24-volts circuit is protected by a 10 amp fuse in a or wire guide train (casing, drive rolls, liners and
panel mounted fuseholder, accessible from the wire contact tip). If this inspection indicates trouble in
the Feeder, use Troubleshooting Guide, Table II
and schematic diagram (Figure 5.1).
23

5.3.1 IF MOTOR DOES NOT RUN: General Replacement
A. Check for blown fuse. If blown, check that motor is The exploded views in the Parts Section indicate gener-
not binding before replacing fuse. ally, in numbered parts sequence, the disassembly of the
wire drive and feeder parts.
B. Check for continuity across speed potentiometer
(POT) and wiper contact. Voltage from center tap Reassemble in reverse order.
to MIN end should vary from 0 to 5.4 VDC as pot-
entiometer is rotated clockwise. 5.3.3 SOLENOID VALVE REPLACEMENT
C. Check wiring for continuity. Then turn power ON When replacing the gas solenoid valve, the inlet (with the
and check for 30 volts d.c. across input terminals word IN) must face the rear of the Unit.
8 and 9 on the feeder printed circuit board connec-
tor (PL1).
D. Press torch trigger, and check for voltage across

motor (Pins 4 to 7) of speed control board; should Many troubleshooting situations require that the
vary from 1 to 24 VDC as speed control potentiom- power remain On and that power terminals in the
eter is rotated clockwise. equipment carry voltage. Exercise extreme caution
when working on LIVE equipment. Avoid contact
5.3.2 DRIVE ROLL PRESSURE ADJUSTMENT with electrical components, except when testing
with an appropriate instrument.
Adjust the drive roll pressure knob until no wire slippage
occurs. DO NOT OVERTIGHTEN - EXCESSIVE PRES-
SURE CAN CAUSE WIRE FEEDING PROBLEMS.
Do not make any repairs to equipment unless you
are fully qualified, as described in the maintenance
section.
TABLE II. TROUBLESHOOTING GUIDE
WELD CONDITION POSSIBLE CAUSE REMEDY
1. No weld or control power. a. Primary input power not available. a. Check for Voltage at primary input.
b. Faulty connection, primary input b. Repair or replace cable or switch
cable, or power switch (TGS1) (TGS1) as necessary.
c. Blown line fuse. c. Replace fuse. If it blows again,
contact L-TEC representative.
2. No welding power. a. Thermostat has opened. a. Wait 15 minutes with fan running. If
still no power, contact L-TEC repre-
sentative.
b. Shorted diode in main rectifier. b. Check diodes and replace if reqd.
c. Open in wiring c. Check all wiring.
3. Fan does not run. a. See Weld Condition 1. a. Repair or replace cable or switch
as necessary.
b. Defective fan motor (MTR1) b. Replace fan motor (MTR1).
4. Erratic welding current. a. Poor workpiece connection. a. Check workpiece grounding

connection.
b. Loose welding connections. b. Check all connections.
c. Wrong polarity. c. Check for correct polarity.
5. Welding output Voltage a. Low line Voltage. a. Use correct Voltage.

and/or current too low. b. Welding cables too long or too b. Use correct cable size.
small.
24

c. Loose connection. c. Check all welding cable

connections.
d. Defective capacitor bank. d. Check capacitors for low
leakage resistance.
6. Stringy irregular bead, a. Torch moved too fast. a. Move Torch slower along seams.
poor penetration. b. Controls are not set properly for b. Reset control properly.
metal gauge thickness.
c. Wrong polarity. c. Check for correct polarity.
7. Bead not centered. a. Nozzle not aligned. a. Move Torch nozzle parallel to
and centered over seam.
8. Bead too large. a. Torch moved too slowly. a. Move Torch faster along seam.
9. Unstable arc, excess a. Incorrectly set controls. a. Reset controls.

spatter, weld porous.
b. Shield gas flow is too low or b. See Condition 10.
stopped.
c. Torch nozzle is too far from work. c. Maintain 1/4" (.6 cm) wire
protrusion; hold closer to work.
d. Faulty regulator or adapter. d. Check flow at outlet;
replace faulty item.
e. Faulty gas solenoid valve (SOL). e. Replace solenoid valve.
f. Wrong polarity. f. Check polarity.
10.Shield gas flow low or a. Cylinder valve closed. a. Turn off regulator, slowly open
stopped valve, until regulator reaches
35 c.f.h. pressure.
b. Cylinder empty. b. Replace if gauge so indicates.
c. Faulty regulator or adaptor. c. Check flow at outlet; replace
faulty item.
d. Faulty gas solenoid valve. d. Replace solenoid valve.
11.Wire stubs on work a. Controls not set properly for a. Reset controls properly.
while welding. metal gauge, thickness.
12.Wire burns back into a. Contact tip loose. a. Firmly tighten with pliers.
contact tip. b. Tip too close to work. b. Maintain 1/4" (.6 cm) wire
protrusion; hold Torch further
from work.
c. Wire feed slipping. c. Increase pressure on pressure
roll by adjusting pressure knob.
d. Contact tip damaged. d. Trim back tip 1/16" (1.6 cm) max.
Replace if still faulty.
e. Voltage setting too high. e. Adjust setting.
f. Drive or pressure roll dirty or worn. f. Clean rolls or replace.
13.Wire does not feed; motor a. Kink, etc. in wire, or wire bound a. Straighten; or feed wire until
running (drive roll turns). on reel. clear and cut off.
b. Wire freezing to contact tip b. Free freeze, or remove contact
(burnback). tip feed wire until clear cut end free,
and replace tip.
c. Clogged liner. c. Replace liner.
25

14.Wire does not feed; a. Motor a. With wire speed dial on 10,
motor NOT running press trigger. If voltage
(drive roll does not turn). appears across motor leads
but motor does not run, check
motor gears and commutator
areas.
b.Power switch TGS1 and fuses. b. With TGS1 ON, if voltage
across terminal 1 and 3 is 24 VAC,
switch and fuses are good.
c. Speed Potentiometer (POT). c. Check for 1K ohms across
POT outside terminals.
d. Defective speed control board. d. Check board voltages
(Para 5.3.1 b. and c.)
15.Wire feed does not stop. a. Torch trigger switch. a. Check continuity of Torch trigger
circuit; check to see if trigger lever
is stuck in ON position.
b. CR1 b. Check for proper action.
16.Gas continues to flow a. Gas solenoid valve stuck open. a. Tap solenoid or click on and off
after trigger release. to clear valve.
VI. PARTS Attaching hardware items are listed, deeply indented,

below the part they attach. They may not be shown.
6.1 SPARE PARTS Order them separately.
To assure minimum downtime, it is recommended that 6.3 ORDERING

the spare parts noted by the symbol (*) in the Stock No.
column of the parts list be kept on hand. To assure proper operation, it is recommended that only
genuine ESAB parts and products be used with this
6.2 REPLACEMENT PARTS equipment. To order replacement parts:
a. Give the part number, description and quantity of

The following illustrations of the equipment identify each
each part required.
replacement part by item number as tabulated in the
related parts lists. The list identifies each part by part, b. Give part number and description of equipment on
number, description, and quantity used (in parentheses, which the parts are to be used.
if more than 1). Some assemblies can be ordered as
complete units or broken down as individual parts. c. Indicate any special shipping instructions.
These parts are listed - indented one space - below the
assembly. When any of the parts can be broken down as
a sub-assembly, its individual parts as listed below it -
indented two spaces.
26

D-32860

27
*NOTE: Switch position mumbers refer to numbers on back of switch
WORK
CONNECTION NOTE: Recent modifications to the power source may not be reflected in this schematic. For up-to-date
information on your model, refer to the schematic on the inside cover of the power source or
contact the factory.
Figure 5.1 - Schematic Migmaster 250 for 208/230 V. Model

D-33310 PRIMARY VOLTAGE CONNECTION CHART
VOLTAGE CONNECTION NO. OF STRIPS

1-2 1
208 6-7 1
7-8 FLEX
1-2 1
230 6-7 1
5-8 FLEX
380 3-7 2
4-8 FLEX
400 2-6 2
7-8 FLEX
460 2-6 2

4-8 FLEX
575 2-3 2
4-8 FLEX
28
WORK
CONNECTION
*NOTE: Switch position numbers refer to numbers on back of switch
NOTE: Recent modifications to the power source may not be reflected in this schematic. For up-to-date information on your
model, refer to the schematic on the inside cover of the power source or contact the factory.
Figure 5.2 - Schematic Migmaster 250 for 208/230/380/400/460/575 V. Model

D-32861

29
Figure 5.3 - Wilring Migmaster 250 for 208/230 V. Model
D-33311

30
Figure 5.4 - Wiring Migmaster 250 for 208/230/380/400/460/575 V. Model
20,
18 16
19 17 14
13
24
21
FAN/CAPACITOR
BANK ASSEMBLY
See Figure 6.4
} 12
1 11 6, 22, 8 10
4 5,
25 7 23
FIGURE 6.1 MIGMASTER 250 MAIN ASSEMBLY (Left Side)
ITEM QTY. PART CKT.

NO. REQ. NO. DESCRIPTION (Figure 6.1) DESIG.
1 1 33184 BASE
4 1 672225 INSULATOR STANDOFF
5 1 1373 6750 TRANSFORMER, MAIN - for 208/230 v. model T1
1 33176 TRANSFORMER, MAIN - for 208-575 v. model T1
6 1 951634 VALVE, SOLENOID, 24 V(from 1/1/94) SOL1
1373 0628 VALVE, SOLENOID (before 1/94)
7 1 951633 CONNECTOR, "Y" from 1/1/94)
2360 6726 HOSE CONNECTION (before 1/94)
8 7 1373 2230 CAPACITOR 10,000 MT, 50V C 1-7
10 2 950396 CASTER, SWIVEL 5"
11 2 1373 0912 WHEEL
12 3 1373 0222 BUSHING
13 1 951672 HANDLE (from 1/1/94)
950695 HANDLE (from 1/94)
14 1 31484 P.C. BOARD, SPEED CONTROL
15 1 2360 8111 TERMINAL BLOCK, 8 PT TB1
16 1 1373 5940 MARKER, TERMINAL
17 2 950760 RELAY (from 1/1/94) K2, K3
2361 0322 RELAY, 4 PDT, 24 VAC, 10A
18 1 1373 0469 BRIDGE, RECTIFIER
19 1 1373 4781 CONTACTOR (see Note below) K1
20 2 1373 0665 BUSBAR E STAMPING
21 1 9951 2178 RESISTOR, 50 OHM, 50W R3
22 1 2360 9967 TERMINAL, 3 POS TB3
23 3 674216 CAPICATOR .02uf 1KV C9-11
24 1 1371 5289 RESISTOR 1 OHM 25W R5
25 1 1373 1989 THERMOSTAT 145° TS1
Capacitor C9-11 and R5 resistor were added 4/93 (starting with Serial No. B93H36548) to provide greater
relay protection.

NOTE: If contactor, 13734781, life is short due to high current, repetitive welding, replace with 60 amp
contactor, 952173.
31

7
11, 12
8 6
21, 22
13,
23, 24
14
5
18, 19
2
15 3
20
10
16, 17
FIGURE 6.2 MIGMASTER 250 SYSTEMS
ITEM QTY PART CKT.

2 1 33188 PANEL, SIDE, RIGHT
3 1 950769 STRAIN, RELIEF
5 2 1373 0623 LATCH, DOOR
6 1 33192 PLATE, COVER*
7 1 33291 COVER, HINGED
8 1 33189 PANEL, CONTROL, SILKSCREENED
10 1 33187 PANEL, SIDE, LEFT
11 1 2360 3918 POTENTIOMETER, IK
12 1 1373 4681 KNOB
13 1 32818 SWITCH ASS'Y., SINGLE POLE, 8 POS.
14 2 2062171 KNOB
15 1 647233 RECEPTACLE, 8 PIN
16 2 2062171 KNOB
17 1 32902 SWITCH ASS'Y., SINGLE POLE, 3 POS.
18 1 951069 PLUG, PLASTIC "C" SIZE
19 1 680552 ADAPTOR, (SPOOL ON GUN)
20 1 950721 SWITCH, TOGGLE
21 1 21165 GUIDE TUBE
22 1 2361 2350 POWER LUG
23 1 2361 0696 ADAPTOR BLOCK ASS'Y.
24 1 2361 0528 HOUSING, ADAPTOR (STRAIGHT)
* Photo shows optional Digital Volt/Ammeter Module, P/N 32857, and Spot/Stitch/Anti-Stick Control Module, P/N 32858.
• Was 97W63, changed to 950769, 6/95.
32

5 9, 10 3 2
7,
6
11
19
14
1
18
20
17
15
16
FIGURE 6.3 MIGMASTER 250 MAIN ASSEMBLY (Right Side)
ITEM QTY PART CKT.

1 1 33186 REAR, PANEL
2 1 2360 5057 SUPPORT, REEL
3 1 2360 6237 HUB, REEL (See Figure 6.5)
5 1 634519 SWITCH, TOGGLE, 4 PDT TGS2
6 1 + - 1373 5464 FUSE, 10A
7 1 1373 1072 HOLDER, FUSE FU1
9 1 2361 2348 GEAR MOTOR, 50-675 IPM
10 1 + - 2361 2479 KEY, MOTOR SHAFT
11 1 33199 COVER P.C. BOARD
14 1 2361 2627 DRIVE STAND ASSEM. (See Fig. 6.6)
15 1 82F31 WORK CLAMP
16 1 1373 2232 FILTER, CHOKE
17 1 951649 POWERCORD
18 1 + - 33450 BUSHING, TERMINAL TP
19 2 676701 TERMINAL ASS'Y., OUTPUT
20l 1 97W63 STRAIN RELIEF
+ - DENOTES RECOMMENDED ON HAND SPARE PART

l
- Added "D" Edition, 3/96
33

5 4, 3 6
10, 9
FIGURE 6.4 MIGMASTER 250 FAN & CAPACITOR BANK
ITEM QTY. PART CKT.

NO. REQ. NO. DESCRIPTION (Detail "B" FAN) DESIG.
2 2 1373 0377 DIODE, SILICON, STRAIGHT POLARITY D1, D2
3 4 1373 0680 INSULATOR, COLLAR
4 4 1373 0681 INSULATOR, SHOULDER
5 2 1373 1597 WELDMENT, RESISTOR
6 2 1373 0378 DIODE, SILICON, REVERSE POLARITY D3, D4
9 1 1373 2227 BLADE, FAN
10 1 1373 2226 MOTOR, FAN M1
8
9 4
REF. 7 6 5
1 2 3
FIGURE 6.5 MIGMASTER 250 LEXAN HUB KIT

ITEM QTY. PART CKT.
NO. REQ. NO. DESCRIPTION (HUB KIT) DESIG.
2360 5780 REEL HUB KIT (INCLUDES 1-8)
1 1 2360 0255 BRAKE, DISC
2 1 2360 6237 HUB, REEL
3 1 2360 0982 SPRING
4 1 2360 0010 NUT
5 1 9204 0101 SCREW, R.H.M., 3/8-16 x .75
6 1 9205 6007 WASHER, PLAIN
7 1 2360 0952 WASHER, "D"
8 1 2360 5057 SUPPORT, REEL
9 1 SHELF (REF.)
34

Figure 6-6. 2-Roll Drive Stand
Item Qty Part

No. Req. No. Description
1 23612627 2 ROLL GEARED WIRE DRIVE SYSTEM, CONSISTS OF:

1 1 23612626 PRESSURE ARM ASSY., (incls. 2, 3, 4, 7, 8)
2 1 23612387 AXLE, PRESSURE ROLL
3 1 23612475 PRESSURE ARM
4 1 23612385 CIRCLIP, PRESSURE ROLL
5 1 23612470 PIVOT PIN
6 2 23612472 CIRCLIP
7 1 23612397 PRESSURE ROLL, SMOOTH
8 1 23612386 GEARED ADAPTOR, PRESSURE ROLL
9 1 23612460 PRESSURE DEVICE ASSY.
10 1 23612473 LOCATING PIN
11 1 23612461 INLET GUIDE
12 1 21156 DRIVE ROLL, .035" - .045"
13 1 23612383 GEARED ADAPTOR DRIVE ROLL
14 1 23612398 FEED ROLL RETAINING SCREW
15 1 23612478 FEED PLATE
16 1 23612479 FEED ROOL KEY
17 1 23612480 MOTOR SHAFT SNAP RING (Not Shown)
18 2 23612384 LOCATING SCREW
19 5 23612462 SCREW
20 1 23612662 SPACER TUBE (Pressure Arm)
21 1 23612663 SPRING PRESSURE ARM
35

ESAB Welding & Cutting Products, Florence, SC Welding Equipment
COMMUNICATIONS GUIDE - CUSTOMER SERVICES
A. CUSTOMER SERVICE QUESTIONS: Telephone (803) 664-5540/Fax: (800) 634-7548

Order Entry Product Availability Pricing Hours: 8:30 AM to 5:00 PM EST
Order Changes Saleable Goods Returns Delivery
Shipping Information
B. ENGINEERING SERVICE: Telephone: (803) 664-4416 / Fax : (800) 446-5693

Welding Equipment Troubleshooting Hours: 7:30 AM to 5:00 PM EST
Warranty Returns Authorized Repair Stations
C. TECHNICAL SERVICE: Telephone: (800) ESAB-123/ Fax: (803) 664-4452

Part Numbers Technical Applications Hours: 8:00 AM to 5:00 PM EST
Performance Features Technical Specifications Equipment Recommendations
D. LITERATURE REQUESTS: Telephone: (803) 664-5501 / Fax: (803) 664-5548

Hours: 7:30 AM to 4:00 PM EST
E. WELDING EQUIPMENT REPAIRS: Telephone: (803) 664-4469 / Fax: (803) 664-5557

Repair Estimates Repair Status Hours: 7:30 AM to 3:30 PM EST
F. WELDING EQUIPMENT TRAINING:

Telephone: (803)664-4428 / Fax: (803) 664-4476
Training School Information and Registrations Hours: 7:30 AM to 4:00 PM EST
G. WELDING PROCESS ASSISTANCE:

Telephone: (803) 664-4248 / Fax: (803) 664-4454 Hours: 7:30 AM to 4:00 PM EST
H. TECHNICAL ASST. CONSUMABLES:

Telephone: (800) 934-9353 Hours: 7:30 AM to 5:00 PM EST
IF YOU DO NOT KNOW WHOM TO CALL
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F-15-087-E 8/97 5M

Migmaster 250: Welding Packages

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Migmaster 250: Welding Packages

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INSTRUCTIONS for F-15-087-E

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SECTION NO. PAGE NO.

SECTION 1 - GENERAL SAFETY RULES FOR WELDING

GENERAL PRECAUTIONS .................................................................................................. 4

SECTION II - INTRODUCTION ............................................................................................. 6

2.1 GENERAL .................................................................................................................. 6

SECTION III - INSTALLATION ............................................................................................. 9

3.1 LOCATION ................................................................................................................. 9

SECTION IV - OPERATION ................................................................................................ 15

4.1 CONTROLS .............................................................................................................. 15

SECTION V - SERVICE ...................................................................................................... 22

5.1 MAINTENANCE ....................................................................................................... 22

SECTION VI - PARTS ......................................................................................................... 26

6.1 SPARE PARTS ........................................................................................................ 26

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POWER SOURCE MIGMASTER 250

Rated Output 250 Amps @ 27 Volts d.c.

Feed Type Push

Conduit Length see section 2.3.1

Net Weight *210 lbs (95 Kg.)

*Includes running gear & bottle tray.

2.3.4 MT-200cc WELDING TORCH (F-15-085), 2.3.6 RUNNING GEAR

2.3.5 CONTROLS 2.4.1 SPOT/STITCH/ANTI-STICK MODULE, P/N

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This easy-to-install, plug-in module mounts in place of

TABLE 2.4.5.1 Recommended MT-200cc Torch Accessories

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Before the equipment is put into operation, the safety

3.1 LOCATION (Figure 3.1)

A proper installation site should be selected for the

The installation site should also permit easy removal of

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Models of this welding machine are designed to be Recommended

B. Input Conductor Connections 208 71 90 8 8

The receptacle should be wired to a separately fused

208/230 MODEL ONLY (With Plug-Cap) 208/230/380/400/460/575-V. MODELS

SINGLE-PHASE THREE-PHASE SINGLE-PHASE THREE-PHASE

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Figure 3.3A - Primary Reconnections at Switch

The terminal labeled GRD is connected to the weld-

C CONNECTING FOR 208 VAC INPUT

D CONNECTING FOR 230 VAC INPUT

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3.4 TORCH CONNECTIONS

The torch (MT-200cc), which is supplied as standard

3.5 WIRE FEEDER MECHANISM

VOLTAGE CONNECTION NO. OF STRIPS 3.5.1 DRIVE ROLLS

Figure 3.3.1-Primary Reconnections at Voltage D. Replace the screws and tighten.

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A. Unscrew spool nut from hub.

Make sure that the proper “outlet guide tube” is inserted

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b. Locate the harness-connected 15-pin plastic plug,