Miller MigMatic 300 User manual

OWNER’S MANUAL
Processes
Description
MIG (GMAW) Welding
Flux Cored (FCAW) Welding
Arc Welding Power Source
Wire Feeder
OM-251958F 2018-02
MigMatic 300/380 And DX
R
CE
File: MIG (GMAW)
For product information,
Owner’s Manual translations,
and more, visit
www.MillerWelds.com

Thank you and congratulations on choosing Miller. Now you can get the
job done and get it done right. We know you don’t have time to do it any
other way.
That’s why when Niels Miller first started building arc welders in 1929,
he made sure his products offered long-lasting value and superior quality.
Like you, his customers couldn’t afford anything less. Miller products had
to be more than the best they could be. They had to be the best you could
buy.
Today, the people that build and sell Miller products continue the
tradition. They’re just as committed to providing equipment and service
that meets the high standards of quality and value established in 1929.
This Owner’s Manual is designed to help you get the most out of your
Miller products. Please take time to read the Safety precautions. They will
help you protect yourself against potential hazards on the worksite. We’ve
made installation and operation quick and easy. With Miller you can
count on years of reliable service with proper maintenance. And if for
some reason the unit needs repair, there’s a Troubleshooting section that
will help you figure out what the problem is. The parts list will then help
you to decide which exact part you may need to fix the problem.
Warranty and service information for your particular model are also
provided.
Miller Electric manufactures a full line of
welders and welding related equipment. For
information on other quality Miller products, contact your local Miller
distributor to receive the latest full line catalog or individual catalog sheets.
Working as hard as you do
−every power source from
Miller is backed by the most
hassle-free warranty in the
business.
From Miller to You

TABLE OF CONTENTS
SECTION 1 −SAFETY PRECAUTIONS - READ BEFORE USING 1.................................
1-1. Symbol Usage 1.......................................................................
1-2. Arc Welding Hazards 1.................................................................
1-3. Additional Symbols For Installation, Operation, And Maintenance 3.............................
1-4. California Proposition 65 Warnings 4......................................................
1-5. Principal Safety Standards 4.............................................................
1-6. EMF Information 4.....................................................................
SECTION 2 −DEFINITIONS 5..................................................................
2-1. Additional Safety Symbols And Definitions 5................................................
2-2. Miscellaneous Symbols And Definitions 7..................................................
SECTION 3 −SPECIFICATIONS 8..............................................................
3-1. Serial Number And Rating Label Location 8................................................
3-2. Specifications 8........................................................................
3-3. Duty Cycle And Overheating 8...........................................................
3-4. Volt-Ampere Curves 9..................................................................
3-5. Environmental Specifications 10...........................................................
SECTION 4 −INSTALLATION 11................................................................
4-1. Installing Gas Supply 11.................................................................
4-2. Installing Wire Spool And Adjusting Hub Tension 12...........................................
4-3. Positioning Jumper Links (230/400V 3-Phase Models) 13......................................
4-4. Electrical Service Guide 14...............................................................
4-5. Connecting 3-Phase Input Power 16.......................................................
4-6. Changing Drive Rolls And Wire Inlet Guide (MigMatic 380 Models) 18...........................
4-7. Aligning Drive Rolls and Wire Guide 20.....................................................
4-8. Threading Welding Wire And Adjusting Pressure Roll Tension 21...............................
SECTION 5 −OPERATION 22...................................................................
5-1. Controls For MigMatic 300 22.............................................................
5-2. Controls For MigMatic 380 23.............................................................
5-3. Selecting Parameters (MigMatic 300 And 380 Models) 24......................................
5-4. Sequencer Controls Settings (MigMatic 300 And 380 Models) 25...............................
5-5. Trigger Mode And Spot Time Selection (MigMatic 300 And 380 Models) 26.......................
5-6. Welding Wire Loading Settings (MigMatic 300 And 380 Models) 27..............................
5-7. Resetting Unit To Factory Default Settings (MigMatic 300 And 380 Models) 28....................
5-8. Controls For MigMatic 300DX 29..........................................................
5-9. Controls For MigMatic 380DX 30..........................................................
5-10. Burnback And Run-In Controls (DX Models Only) 31..........................................
5-11. Welding Power Source Input Line Voltage Adjustment (DX Models Only) 32......................
5-12. Welding Power Source Setup Menu (DX Models Only) 33.....................................
5-13. Trigger Mode Selection (DX Models Only) 34................................................
5-14. Welding Wire Diameter Selection For Synergic MIG (DX Models Only) 34........................
5-15. Welding Wire Type Selection For Synergic MIG (DX Models Only) 35............................
5-16. Gas Selection For Synergic MIG (DX Models Only) 35........................................
5-17. Selecting Manual MIG Welding (DX Models Only) 36..........................................
5-18. Selecting Synergic MIG Welding (DX Models Only) 37........................................
SECTION 6 −MAINTENANCE &TROUBLESHOOTING 38..........................................
6-1. Routine Maintenance 38.................................................................
6-2. Welding Gun And Wire Drive Assembly 38..................................................
6-3. Unit Overload 38........................................................................
6-4. Troubleshooting 39......................................................................
SECTION 7 −ELECTRICAL DIAGRAMS 40.......................................................
SECTION 8 −PARTS LIST 48...................................................................
WARRANTY

DECLARATION OF CONFORMITY
for European Community (CE marked) products.
ITW Welding Italy S.r.l Via Privata Iseo 6/E, 20098 San Giuliano M.se, (MI) Italy declares that the prod
uct(s) identified in this declaration conform to the essential requirements and provisions of the stat
ed Council Directive(s) and Standard(s).
Product/Apparatus Identification:
Product Stock Number
MIGMATIC 300, 400VAC 029015540
MIGMATIC 300 DX, 400VAC 029015541
MIGMATIC 300, 230/400VAC 029015545
MIGMATIC 300 DX, 230/400VAC 029015546
MIGMATIC 380, 400VAC 029015542
MIGMATIC 380 DX, 400VAC 029015543
MIGMATIC 380, 230/400VAC 029015547
MIGMATIC 380 DX, 230/400VAC 029015548
Council Directives:
• 2006/95/EC Low Voltage
• 2004/108/EC Electromagnetic Compatibility
• 2011/65/EU Restriction of the use of certain hazardous substances in electrical and electronic equipment
Standards:
• IEC 60974-1:2012 Arc Welding Equipment – Part 1: Welding Power Sources
• IEC 60974-5:2007 Arc Welding Equipment – Part 5: Wire Feeders
• IEC 60974-10:2007 Arc Welding Equipment – Part 10: Electromagnetic Compatibility Requirements
EU Signatory:
July 1st, 2015
___________________________________________________________________________________
Massimigliano Lavarini Date of Declaration
ITW WELDING ITALY PRODUCTION MANAGER
956 172 215

EMF DATA SHEET FOR ARC WELDING POWER SOURCE
Product/Apparatus Identification
Product Stock Number
MIGMATIC 380, 400VAC 029015542
MIGMATIC 380 DX, 400VAC 029015543
MIGMATIC 380, 230/400VAC 029015547
MIGMATIC 380 DX, 230/400VAC 029015548
Compliance Information Summary
Applicable regulation Directive 2014/35/EU
Reference limits Directive 2013/35/EU, Recommendation 1999/519/EC
Applicable standards IEC 62822−1:2016, IEC 62822−2:2016
Intended use ☒for occupational use ☐for use by laymen
Non−thermal effects need to be considered for workplace assessment ☒YES ☐NO
Thermal effects need to be considered for workplace assessment ☐YES ☒NO
☒Data is based on maximum power source capability (valid unless firmware/hardware is changed)
☐Data is based on worst case setting/program (only valid until setting options/welding programs are changed)
☐Data is based on multiple settings/programs (only valid until setting options/welding programs are changed)
Occupational exposure is below the Exposure Limit Values (ELVs) ☒YES ☐NO
for health effects at the standardized configurations (if NO, specific required minimum distances apply)
Occupational exposure is below the Exposure Limit Values (ELVs) ☐n.a ☒YES ☐NO
for sensory effects at the standardized configurations (if applicable and NO, specific measures are needed)
Occupational exposure is below the Action Levels (ALs) at the ☐n.a ☐YES ☒NO
standardized configurations (if applicable and NO, specific signage is needed)
EMF Data for Non−thermal Effects
Exposure Indices (EIs) and distances to welding circuit (for each operation mode, as applicable)
Head
Trunk Limb (hand) Limb (thigh)
Sensory
Effects
Health
Effects
Standardized distance 10 cm 10 cm 10 cm 3 cm 3 cm
ELV EI @ standardized distance 0.06 0.02 0.02 0.02 0.03
Required minimum distance 1 cm 1 cm 1 cm 1 cm 1 cm
Distance where all occupational ELV Exposure Indices fall below 0.20 (20%) 1 cm
Distance where all general public ELV Exposure Indices fall below 1.00 (100%) 10 cm
Tested by: Tony Samimi Date tested: 2017−02−20
956172333

EMF DATA SHEET FOR ARC WELDING POWER SOURCE
Product/Apparatus Identification
Product Stock Number
MIGMATIC 300, 400VAC 029015540
MIGMATIC 300 DX, 400VAC 029015541
MIGMATIC 300, 230/400VAC 029015545
MIGMATIC 300 DX, 230/400VAC 029015546
Compliance Information Summary
Applicable regulation Directive 2014/35/EU
Reference limits Directive 2013/35/EU, Recommendation 1999/519/EC
Applicable standards IEC 62822−1:2016, IEC 62822−2:2016
Intended use ☒for occupational use ☐for use by laymen
Non−thermal effects need to be considered for workplace assessment ☒YES ☐NO
Thermal effects need to be considered for workplace assessment ☐YES ☒NO
☒Data is based on maximum power source capability (valid unless firmware/hardware is changed)
☐Data is based on worst case setting/program (only valid until setting options/welding programs are changed)
☐Data is based on multiple settings/programs (only valid until setting options/welding programs are changed)
Occupational exposure is below the Exposure Limit Values (ELVs) ☒YES ☐NO
for health effects at the standardized configurations (if NO, specific required minimum distances apply)
Occupational exposure is below the Exposure Limit Values (ELVs) ☐n.a ☒YES ☐NO
for sensory effects at the standardized configurations (if applicable and NO, specific measures are needed)
Occupational exposure is below the Action Levels (ALs) at the ☐n.a ☐YES ☒NO
standardized configurations (if applicable and NO, specific signage is needed)
EMF Data for Non−thermal Effects
Exposure Indices (EIs) and distances to welding circuit (for each operation mode, as applicable)
Head
Trunk Limb (hand) Limb (thigh)
Sensory
Effects
Health
Effects
Standardized distance 10 cm 10 cm 10 cm 3 cm 3 cm
ELV EI @ standardized distance 0.06 0.02 0.02 0.02 0.03
Required minimum distance 1 cm 1 cm 1 cm 1 cm 1 cm
Distance where all occupational ELV Exposure Indices fall below 0.20 (20%) 1 cm
Distance where all general public ELV Exposure Indices fall below 1.00 (100%) 16 cm
Tested by: Tony Samimi Date tested: 2018 −01−24
956172332

OM-251958 Page 1
SECTION 1 −SAFETY PRECAUTIONS - READ BEFORE USING
som 2018−01
7
Protect yourself and others from injury — read, follow, and save these important safety precautions and operating instructions.
1-1. Symbol Usage
DANGER! −Indicates a hazardous situation which, if
not avoided, will result in death or serious injury. The
possible hazards are shown in the adjoining symbols
or explained in the text.
Indicates a hazardous situation which, if not avoided,
could result in death or serious injury. The possible
hazards are shown in the adjoining symbols or ex-
plained in the text.
NOTICE −Indicates statements not related to personal injury.
.Indicates special instructions.
This group of symbols means Warning! Watch Out! ELECTRIC
SHOCK, MOVING PARTS, and HOT PARTS hazards. Consult sym-
bols and related instructions below for necessary actions to avoid the
hazards.
1-2. Arc Welding Hazards
The symbols shown below are used throughout this manual
to call attention to and identify possible hazards. When you
see the symbol, watch out, and follow the related instructions
to avoid the hazard. The safety information given below is
only a summary of the more complete safety information
found in the Safety Standards listed in Section 1-5. Read and
follow all Safety Standards.
Only qualified persons should install, operate, maintain, and
repair this equipment. A qualified person is defined as one
who, by possession of a recognized degree, certificate, or
professional standing, or who by extensive knowledge, train-
ing and experience, has successfully demonstrated ability to
solve or resolve problems relating to the subject matter, the
work, or the project and has received safety training to recog-
nize and avoid the hazards involved.
During operation, keep everybody, especially children, away.
Touching live electrical parts can cause fatal shocks
or severe burns. The electrode and work circuit is
electrically live whenever the output is on. The input
power circuit and machine internal circuits are also
live when power is on. In semiautomatic or automatic
wire welding, the wire, wire reel, drive roll housing,
and all metal parts touching the welding wire are
electrically live. Incorrectly installed or improperly
grounded equipment is a hazard.
DDo not touch live electrical parts.
ELECTRIC SHOCK can kill.
DWear dry, hole-free insulating gloves and body protection.
DInsulate yourself from work and ground using dry insulating mats
or covers big enough to prevent any physical contact with the work
or ground.
DDo not use AC weld output in damp, wet, or confined spaces, or if
there is a danger of falling.
DUse AC output ONLY if required for the welding process.
DIf AC output is required, use remote output control if present on
unit.
DAdditional safety precautions are required when any of the follow-
ing electrically hazardous conditions are present: in damp
locations or while wearing wet clothing; on metal structures such
as floors, gratings, or scaffolds; when in cramped positions such
as sitting, kneeling, or lying; or when there is a high risk of unavoid-
able or accidental contact with the workpiece or ground. For these
conditions, use the following equipment in order presented: 1) a
semiautomaticDC constant voltage (wire) welder, 2) a DC manual
(stick) welder, or 3) an AC welder with reduced open-circuit volt-
age. In most situations, use of a DC, constant voltage wire welder
is recommended. And, do not work alone!
DDisconnect input power or stop engine before installing or
servicing this equipment. Lockout/tagout input power according to
OSHA 29 CFR 1910.147 (see Safety Standards).
DProperly install, ground, and operate this equipment according to
its Owner’s Manual and national, state, and local codes.
DAlways verify the supply ground −check and be sure that input
power cord ground wire is properly connected to ground terminal in
disconnect box or that cord plug is connected to a properly
grounded receptacle outlet.
DWhen making input connections, attach proper grounding conduc-
tor first −double-check connections.
DKeep cords dry, free of oil and grease, and protected from hot metal
and sparks.
DFrequently inspect input power cord and ground conductor for
damage or bare wiring – replace immediately if damaged – bare
wiring can kill.
DTurn off all equipment when not in use.
DDo not use worn, damaged, undersized, or repaired cables.
DDo not drape cables over your body.
DIf earth grounding of the workpiece is required, ground it directly
with a separate cable.
DDo not touch electrode if you are in contact with the work, ground,
or another electrode from a different machine.
DDo not touch electrode holders connected to two welding ma-
chines at the same time since double open-circuit voltage will be
present.
DUse only well-maintained equipment. Repair or replace damaged
parts at once. Maintain unit according to manual.
DWear a safety harness if working above floor level.
DKeep all panels and covers securely in place.
DClamp work cable with good metal-to-metal contact to workpiece
or worktable as near the weld as practical.
DInsulate work clamp when not connected to workpiece to prevent
contact with any metal object.
DDo not connect more than one electrode or work cable to any
single weld output terminal. Disconnect cable for process not in
use.
DUse GFCI protection when operating auxiliary equipment in damp
or wet locations.
SIGNIFICANT DC VOLTAGE exists in inverter weld-
ing power sources AFTER removal of input power.
DTurn off unit, disconnect input power, and discharge input capaci-
tors according to instructions in Manual before touching any parts.
HOT PARTS can burn.
DDo not touch hot parts bare handed.
DAllow cooling period before working on
equipment.
DTo handle hot parts, use proper tools and/or wear heavy, insu-
lated welding gloves and clothing to prevent burns.

OM-251958 Page 2
Welding produces fumes and gases. Breathing
these fumes and gases can be hazardous to your
health.
FUMES AND GASES can be hazardous.
DKeep your head out of the fumes. Do not breathe the fumes.
DVentilate the work area and/or use local forced ventilation at the arc
to remove welding fumes and gases. The recommended way to
determine adequate ventilation is to sample for the composition
and quantity of fumes and gases to which personnel are exposed.
DIf ventilation is poor, wear an approved air-supplied respirator.
DRead and understand the Safety Data Sheets (SDSs) and the
manufacturer’s instructions for adhesives, coatings, cleaners,
consumables, coolants, degreasers, fluxes, and metals.
DWork in a confined space only if it is well ventilated, or while
wearing an air-supplied respirator. Always have a trained watch-
person nearby. Welding fumes and gases can displace air and
lower the oxygen level causing injury or death. Be sure the breath-
ing air is safe.
DDo not weld in locations near degreasing, cleaning, or spraying op-
erations. The heat and rays of the arc can react with vapors to form
highly toxic and irritating gases.
DDo not weld on coated metals, such as galvanized, lead, or
cadmium plated steel, unless the coating is removed from the weld
area, the area is well ventilated, and while wearing an air-supplied
respirator. The coatings and any metals containing these elements
can give off toxic fumes if welded.
Arc rays from the welding process produce intense
visible and invisible (ultraviolet and infrared) rays
that can burn eyes and skin. Sparks fly off from the
weld.
DWear an approved welding helmet fitted with a proper shade of
filter lenses to protect your face and eyes from arc rays and
sparks when welding or watching (see ANSI Z49.1 and Z87.1
listed in Safety Standards).
DWear approved safety glasses with side shields under your
helmet.
DUse protective screens or barriers to protect others from flash,
glare and sparks; warn others not to watch the arc.
DWear body protection made from durable, flame−resistant mate-
rial (leather, heavy cotton, wool). Body protection includes
oil-free clothing such as leather gloves, heavy shirt, cuffless
trousers, high shoes, and a cap.
ARC RAYS can burn eyes and skin.
Welding on closed containers, such as tanks,
drums, or pipes, can cause them to blow up. Sparks
can fly off from the welding arc. The flying sparks, hot
workpiece, and hot equipment can cause fires and
burns. Accidental contact of electrode to metal objects can cause
sparks, explosion, overheating, or fire. Check and be sure the area is
safe before doing any welding.
WELDING can cause fire or explosion.
DRemove all flammables within 35 ft (10.7 m) of the welding arc. If
this is not possible, tightly cover them with approved covers.
DDo not weld where flying sparks can strike flammable material.
DProtect yourself and others from flying sparks and hot metal.
DBe alert that welding sparks and hot materials from welding can
easily go through small cracks and openings to adjacent areas.
DWatch for fire, and keep a fire extinguisher nearby.
DBe aware that welding on a ceiling, floor, bulkhead, or partition can
cause fire on the hidden side.
DDo not cut or weld on tire rims or wheels. Tires can explode if heat-
ed. Repaired rims and wheels can fail. See OSHA 29 CFR
1910.177 listed in Safety Standards.
DDo not weld on containers that have held combustibles, or on
closed containers such as tanks, drums, or pipes unless they are
properly prepared according to AWS F4.1 and AWS A6.0 (see
Safety Standards).
DDo not weld where the atmosphere can contain flammable dust,
gas, or liquid vapors (such as gasoline).
DConnect work cable to the work as close to the welding area as
practical to prevent welding current from traveling long, possibly
unknown paths and causing electric shock, sparks, and fire
hazards.
DDo not use welder to thaw frozen pipes.
DRemove stick electrode from holder or cut off welding wire at
contact tip when not in use.
DWear body protection made from durable, flame−resistant material
(leather, heavy cotton, wool). Body protection includes oil-free
clothing such as leather gloves, heavy shirt, cuffless trousers, high
shoes, and a cap.
DRemove any combustibles, such as a butane lighter or matches,
from your person before doing any welding.
DAfter completion of work, inspect area to ensure it is free of sparks,
glowing embers, and flames.
DUse only correct fuses or circuit breakers. Do not oversize or by-
pass them.
DFollow requirements in OSHA 1910.252 (a) (2) (iv) and NFPA 51B
for hot work and have a fire watcher and extinguisher nearby.
DRead and understand the Safety Data Sheets (SDSs) and the
manufacturer’s instructions for adhesives, coatings, cleaners,
consumables, coolants, degreasers, fluxes, and metals.
FLYING METAL or DIRT can injure eyes.
DWelding, chipping, wire brushing, and grinding
cause sparks and flying metal. As welds cool,
they can throw off slag.
DWear approved safety glasses with side
shields even under your welding helmet.
BUILDUP OF GAS can injure or kill.
DShut off compressed gas supply when not in use.
DAlways ventilate confined spaces or use
approved air-supplied respirator.
ELECTRIC AND MAGNETIC FIELDS (EMF
)
can affect Implanted Medical Devices.
DWearers of Pacemakers and other Implanted
Medical Devices should keep away.
DImplanted Medical Device wearers should consult their doctor
and the device manufacturer before going near arc welding, spot
welding, gouging, plasma arc cutting, or induction heating
operations.
Noise from some processes or equipment can
damage hearing.
DWear approved ear protection if noise lev-
el is high.
NOISE can damage hearing.

OM-251958 Page 3
Compressed 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.
CYLINDERS can explode if damaged.
DProtect compressed gas cylinders from excessive heat, mechani-
cal shocks, physical damage, slag, open flames, sparks, and arcs.
DInstall cylinders in an upright position by securing to a stationary
support or cylinder rack to prevent falling or tipping.
DKeep cylinders away from any welding or other electrical circuits.
DNever drape a welding torch over a gas cylinder.
DNever allow a welding electrode to touch any cylinder.
DNever weld on a pressurized cylinder −explosion will result.
DUse only correct compressed gas cylinders, regulators, hoses,
and fittings designed for the specific application; maintain them
and associated parts in good condition.
DTurn face away from valve outlet when opening cylinder valve. Do
not stand in front of or behind the regulator when opening the valve.
DKeep protective cap in place over valve except when cylinder is in
use or connected for use.
DUse the proper equipment, correct procedures, and sufficient
number of persons to lift, move, and transport cylinders.
DRead and follow instructions on compressed gas cylinders,
associated equipment, and Compressed Gas Association (CGA)
publication P-1 listed in Safety Standards.
1-3. Additional Symbols For Installation, Operation, And Maintenance
FIRE OR EXPLOSION hazard.
DDo not install or place unit on, over, or near
combustible surfaces.
DDo not install unit near flammables.
DDo not overload building wiring −be sure power supply system is
properly sized, rated, and protected to handle this unit.
FALLING EQUIPMENT can injure.
DUse lifting eye to lift unit only, NOT running
gear, gas cylinders, or any other accessories.
DUse correct procedures and equipment of ade-
quate capacity to lift and support unit.
DIf using lift forks to move unit, be sure forks are long enough to
extend beyond opposite side of unit.
DKeep equipment (cables and cords) away from moving vehicles
when working from an aerial location.
DFollow the guidelines in the Applications Manual for the Revised
NIOSH Lifting Equation (Publication No. 94−110) when manu-
ally lifting heavy parts or equipment.
OVERUSE can cause OVERHEATING
DAllow cooling period; follow rated duty cycle.
DReduce current or reduce duty cycle before
starting to weld again.
DDo not block or filter airflow to unit.
FLYING SPARKS can injure.
DWear a face shield to protect eyes and face.
DShape tungsten electrode only on grinder with
proper guards in a safe location wearing proper
face, hand, and body protection.
DSparks can cause fires — keep flammables away.
STATIC (ESD) can damage PC boards.
DPut on grounded wrist strap BEFORE handling
boards or parts.
DUse proper static-proof bags and boxes to
store, move, or ship PC boards.
MOVING PARTS can injure.
DKeep away from moving parts.
DKeep away from pinch points such as drive
rolls.
WELDING WIRE can injure.
DDo not press gun trigger until instructed to do
so.
DDo not point gun toward any part of the body,
other people, or any metal when threading
welding wire.
BATTERY EXPLOSION can injure.
DDo not use welder to charge batteries or jump
start vehicles unless it has a battery charging
feature designed for this purpose.
MOVING PARTS can injure.
DKeep away from moving parts such as fans.
DKeep all doors, panels, covers, and guards
closed and securely in place.
DHave only qualified persons remove doors, panels, covers, or
guards for maintenance and troubleshooting as necessary.
DReinstall doors, panels, covers, or guards when maintenance is
finished and before reconnecting input power.
READ INSTRUCTIONS.
DRead and follow all labels and the Owner’s
Manual carefully before installing, operating, or
servicing unit. Read the safety information at
the beginning of the manual and in each
section.
DUse only genuine replacement parts from the manufacturer.
DPerform installation, maintenance, and service according to the
Owner’s Manuals, industry standards, and national, state, and
local codes.

OM-251958 Page 4
H.F. RADIATION can cause interference.
DHigh-frequency (H.F.) can interfere with radio
navigation, safety services, computers, and
communicationsequipment.
DHave only qualified persons familiar with electronic equipment
perform this installation.
DThe user is responsible for having a qualified electrician prompt-
ly correct any interference problem resulting from the installa-
tion.
DIf notified by the FCC about interference, stop using the
equipment at once.
DHave the installation regularly checked and maintained.
DKeep high-frequency source doors and panels tightly shut, keep
spark gaps at correct setting, and use grounding and shielding to
minimize the possibility of interference.
ARC WELDING can cause interference.
DElectromagnetic energy can interfere with
sensitive electronic equipment such as
computers and computer-driven equipment
such as robots.
DBe sure all equipment in the welding area is electromagnetically
compatible.
DTo reduce possible interference, keep weld cables as short as
possible, close together, and down low, such as on the floor.
DLocate welding operation 100 meters from any sensitive elec-
tronic equipment.
DBe sure this welding machine is installed and grounded
according to this manual.
DIf interference still occurs, the user must take extra measures
such as moving the welding machine, using shielded cables,
using line filters, or shielding the work area.
1-4. California Proposition 65 Warnings
WARNING: This product can expose you to chemicals in-
cluding lead, which are known to the state of California to
cause cancer and birth defects or other reproductive
harm.
For more information, go to www.P65Warnings.ca.gov.
1-5. Principal Safety Standards
Safety in Welding, Cutting, and Allied Processes, ANSI Standard Z49.1,
is available as a free download from the American Welding Society at
http://www.aws.org or purchased from Global Engineering Documents
(phone: [phone], website: www.global.ihs.com).
Safe Practices for the Preparation of Containers and Piping for Welding
and Cutting, American Welding Society Standard AWS F4.1, from Glob-
al Engineering Documents (phone: [phone], website:
www.global.ihs.com).
Safe Practices for Welding and Cutting Containers that have Held Com-
bustibles, American Welding Society Standard AWS A6.0, from Global
EngineeringDocuments (phone: [phone],
website: www.global.ihs.com).
National Electrical Code, NFPA Standard 70, from National Fire Protec-
tion Association, Quincy, MA 02169 (phone: [phone], website:
www.nfpa.org and www. sparky.org).
Safe Handling of Compressed Gases in Cylinders, CGA Pamphlet P-1,
from Compressed Gas Association, 14501 George Carter Way, Suite
103, Chantilly, VA 20151 (phone: [phone], website:www.cga-
net.com).
Safety in Welding, Cutting, and Allied Processes, CSA Standard
W117.2, from Canadian Standards Association, Standards Sales, 5060
Spectrum Way, Suite 100, Mississauga, Ontario, Canada L4W 5NS
(phone: [phone], website: www.csagroup.org).
Safe Practice For Occupational And Educational Eye And Face Protec-
tion, ANSI Standard Z87.1, from American National Standards Institute,
25 West 43rd Street, New York, NY 10036 (phone: [phone], web-
site: www.ansi.org).
Standard for Fire Prevention During Welding, Cutting, and Other Hot
Work, NFPA Standard 51B, from National Fire Protection Association,
Quincy, MA 02169 (phone: [phone], website: www.nfpa.org).
OSHA, Occupational Safety and Health Standards for General Indus-
try, Title 29, Code of Federal Regulations (CFR), Part 1910.177 Subpart
N, Part 1910 Subpart Q, and Part 1926, Subpart J, from U.S. Govern-
ment Printing Office, Superintendent of Documents, P.O. Box 371954,
Pittsburgh, PA 15250-7954 (phone: [phone]) (there are 10 OS-
HA Regional Offices—phone for Region 5, Chicago, is 312-353-2220,
website: www.osha.gov).
Applications Manual for the Revised NIOSH Lifting Equation, The Na-
tional Institute for Occupational Safety and Health (NIOSH), 1600
Clifton Rd, Atlanta, GA 30329-4027 (phone: [phone], website:
www.cdc.gov/NIOSH).
1-6. EMF Information
Electric current flowing through any conductor causes localized electric
and magnetic fields (EMF). The current from arc welding (and allied pro-
cesses including spot welding, gouging, plasma arc cutting, and
induction heating operations) creates an EMF field around the welding
circuit. EMF fields can interfere with some medical implants, e.g. pace-
makers. Protective measures for persons wearing medical implants
have to be taken. For example, restrict access for passers−by or con-
duct individual risk assessment for welders. All welders should use the
following procedures in order to minimize exposure to EMF fields from
the welding circuit:
1. Keep cables close together by twisting or taping them, or using a
cable cover.
2. Do not place your body between welding cables. Arrange cables
to one side and away from the operator.
3. Do not coil or drape cables around your body.
4. Keep head and trunk as far away from the equipment in the
welding circuit as possible.
5. Connect work clamp to workpiece as close to the weld as
possible.
6. Do not work next to, sit or lean on the welding power source.
7. Do not weld whilst carrying the welding power source or wire
feeder.
About Implanted Medical Devices:
Implanted Medical Device wearers should consult their doctor and the
device manufacturer before performing or going near arc welding, spot
welding, gouging, plasma arc cutting, or induction heating operations.
If cleared by your doctor, then following the above procedures is recom-
mended.

OM-251958 Page 5
SECTION 2 −DEFINITIONS
2-1. Additional Safety Symbols And Definitions
.Some symbols are found only on CE products.
Warning! Watch Out! There are possible hazards as shown by the symbols.
Safe1 2012−05
Do not discard product (where applicable) with general waste.
Reuse or recycle Waste Electrical and Electronic Equipment (WEEE) by disposing at a designated collection
facility.
Contact your local recycling office or your local distributor for further information. Safe37 2017−04
Wear dry insulating gloves. Do not touch electrode with bare hand. Do not wear wet or damaged gloves.
Safe2 2017−04
Protect yourself from electric shock by insulating yourself from work and ground.
Safe3 2017−04
Disconnect input plug or power before working on machine.
Safe5 2017−04
Keep your head out of the fumes.
Safe6 2017−04
Use forced ventilation or local exhaust to remove the fumes.
Safe8 2012−05
Use ventilating fan to remove fumes.
Safe10 2012−05
Keep flammables away from welding. Do not weld near flammables.
Safe12 2012−05

OM-251958 Page 6
Welding sparks can cause fires. Have a fire extinguisher nearby, and have a watchperson ready to use it.
Safe14 2012−05
Do not weld on drums or any closed containers.
Safe16 2017−04
Do not remove or paint over (cover) the label.
Safe20 2017−04
Disconnect input plug or power before working on machine.
Safe30 2012−05
Drive rolls can injure fingers.
Safe32 2012−05
Welding wire and drive parts are at welding voltage during operation −keep hands and metal objects away.
Safe33 2017−04
Consult rating label for input power requirements. See rating label on unit and check input voltage available at
site.
Safe34 2012−05
Become trained and read the instructions and labels before working on machine.
Safe35 2012−05
Wear hat and safety glasses. Use ear protection and button shirt
collar. Use welding helmet with correct shade of filter. Wear complete
body protection.
Safe38 2012−05
Kasjf;laksf;lkasdf'l;aksdf;lkasd;flksadflkasd;lk
Kasjf;laksf;lkasdf'l;aksdf;lkasd;flksadflkasd;lk
Kasjf;laksf;lkasdf'l;aksdf;lkasd;flksadflkasd;lk
Become trained and read the instructions before working on the
machine or welding.
Safe40 2012−05

OM-251958 Page 7
31 Safe49 2012−05
Move jumper links as shown on inside label to match input voltage at
job site. Include extra length in grounding conductor and connect
grounding conductor first. Connect line input conductors as shown on
inside label. Double-check all connections, jumper link positions, and
input voltage before applying power.
<10°
Falling unit can cause injury. Do not move or operate unit where it could tip.
Safe53 2017−04
2-2. Miscellaneous Symbols And Definitions
AAmperage
VVolts
Alternating
Current (AC)
Direct Current
(DC)
Remote
On
Off
Protective Earth
(Ground)
Line Connection
Three Phase
Single Phase
Gas Metal Arc
Welding (GMAW)
U1
Primary Voltage
I1max Rated Maximum
Supply Current
I1eff
Maximum
Effective
Supply Current
U2
Conventional
Load Voltage
I2
Rated Welding
Current
XDuty Cycle
Percent
U0
Rated No Load
Voltage (OCV)
IP Degree Of
Protection
Circuit Breaker
Three Phase
Transformer
Rectifier
Two-Step Trigger
Operation
Four-Step Trigger
Operation
Gas Input
Gas Output
Gas Type
Voltage Input
Wire Feed
Hz Hertz
Input
Read Operator’s
Manual
Wire Type
Diameter
tSpot Weld Time
Wire Burnback
Control
Wire Run-In
Speed Control
Low Inductance
High Inductance
Preflow Time
Postflow Time

OM-251958 Page 8
SECTION 3 −SPECIFICATIONS
3-1. Serial Number And Rating Label Location
The serial number and rating information for this product is located on the back. Use rating label to determine input power requirements and/or rated
output. For future reference, write serial number in space provided on back cover of this manual.
3-2. Specifications
.Do not use information in unit specifications table to determine electrical service requirements. See Sections 4-4 and 4-5 for information on con-
necting input power.
.This equipment will deliver rated output at an ambient air temperature up to 1045F ( 405C).
Model
Rated Output Max. Open
Circuit
Voltage
Amperage
Range
DC Dimension (mm)
Weight
(kg)
100% 60% 35%
300*
230/400 VAC
50/60 Hz
180 A
23 V
230 A
25.5 V
300 A
29.0 V 43.5 30-300 A 471 x 825 x 1066 88 Net
Wire feed speed range 1.3 mpm to 26 mpm.
Model
Rated Output Max. Open
Circuit
Voltage
Amperage
Range
DC Dimension (mm) Weight (kg)
100% 60% 35%
380*
230/400 VAC
50/60 Hz
210 A
24.5 V
270 A
27.5 V
350 A
31.5 V 43.0 V 30-350 A 471 x 825 x 1066 102.6 Net
Wire feed speed range 1.3 mpm to 26 mpm.
3-3. Duty Cycle And Overheating
Duty Cycle is percentage of 10 min-
utes that unit can weld at rated load
without overheating.
If unit overheats, thermostat(s)
opens, output stops, and cooling
fan runs. Wait fifteen minutes for
unit to cool. Reduce amperage or
voltage, or duty cycle before
welding.
NOTICE −Exceeding duty cycle
can damage unit and void warranty.
Overheating
0
15
A or V
OR
Reduce Duty Cycle
Minutes
60% Duty Cycle At 270 Amperes 100% Duty Cycle At 210 Amperes
sduty1 5/95
Continuous Welding
% DUTY CYCLE
6 Minutes Welding 4 Minutes Resting

OM-251958 Page 9
3-4. Volt-Ampere Curves
The volt-ampere curves show the
normal minimum and maximum volt-
age and amperage output capabili-
ties of the welding power source.
Curves of other settings fall between
the curves shown.
MigMatic 300
0
5
01
51
02
52
03
53
04
54
05
043023003082062042022002081061041021001080604020
DC Amperes
DC Volts
Max
Min
0
5
01
51
02
52
03
53
04
54
05
024004083063043023003082062042022002081061041021001080604020
MigMatic 380
DC Amperes
DC Volts

OM-251958 Page 10
3-5. Environmental Specifications
A. IP Rating
IP Rating
IP22S
This equipment is designed for indoor use and is not intended to be used or stored outside.
IP22S 2014−06
B. Temperature Specifications
Operating Temperature Range* Storage/Transportation Temperature Range
−10 to 40°C (14 to 104°F)
*Output is derated at temperatures above 40°C (104°F).
−20 to 55°C (−4 to 131°F)
Temp_2016- 07
C. Information On Electromagnetic Compatibility (EMC)
!This Class A equipment is not intended for use in residential locations where the electrical power is provided by the public low−
voltage supply system. There can be potential difficulties in ensuring electromagnetic compatibility in those locations, due to con-
ducted as well as radiated disturbances.
This equipment complies with IEC61000-3-11 and IEC 61000−3−12 and can be connected to public low-voltage systems provided that the public
low-voltage system impedance Zmax at the point of common coupling is less than __mW(or the short−circuit power Ssc is greater than __VA).
It is the responsibility of the installer or user of the equipment to ensure, by consultation with the distribution network operator if necessary, that
the system impedance complies with the impedance restrictions.
ce-emc 1 2014-07
Notes

OM-251958 Page 11
SECTION 4 −INSTALLATION
4-1. Installing Gas Supply
Ref. 148265-B / Ref. 149827-B / Ref. 158697-A
CO2Gas
Argon Gas Or Mixed Gas
OR
1
2
3
1
2
3
Rear Panel
6
4
57
8 9
Obtain gas cylinder and chain to
running gear, wall, or other
stationary support so cylinder
cannot fall and break off valve.
1 Cap
2 Cylinder Valve
Remove cap, stand to side of
valve, and open valve slightly. Gas
flow blows dust and dirt from valve.
Close valve.
3 Cylinder
4 Regulator/Flowmeter
Install so face is vertical.
5 Regulator/Flowmeter Gas
Hose Connection
6 Welding Power Source Gas
Hose Connection
Connect supplied gas hose
between regulator/flowmeter gas
hose connection, and fitting on
rear of welding power source.
7 Flow Adjust
Typical flow rate is between 15-20
liters per minute. Check wire
manufacturer’s recommended
flow rate.
8CO
2Adapter (Customer
Supplied)
9 O-Ring (Customer Supplied)
Install adapter with O-ring between
regulator/flowmeter and CO2
cylinder.

OM-251958 Page 12
4-2. Installing Wire Spool And Adjusting Hub Tension
Ref. D2
Tools Needed:
Hub Assembly
15 Kg Wire Spool
Assembly 5 Kg Wire Spool
Assembly
1 Spacers
Use only for 5Kg spool.
1

OM-251958 Page 13
4-3. Positioning Jumper Links (230/400V 3-Phase Models)
230 Volts
230 Volts
400 Volts
400 Volts
956142845_5_14_A
!Disconnect and lockout/tagout
input power before connecting
input conductors from unit.
Follow established procedures
regarding the installation and
removal of lockout/tagout
devices.
Check input voltage available at site.
1 Jumper Link Label
Check label −only one is on unit.
2 Jumper Links
Move jumper links to match input volt-
age.
Close and secure access door.
Follow established lockout/tagout
procedures to put unit in service.

OM-251958 Page 14
4-4. Electrical Service Guide Elec Serv 2017-01
Failure to follow these electrical service guide recommendations could create an electric shock or fire hazard. These recommenda-
tions are for a dedicated circuit sized for the rated output and duty cycle of the welding power source.
In dedicated circuit installations, the National Electrical Code (NEC) allows the receptacle or conductor rating to be less than the rating
of the circuit protection device. All components of the circuit must be physically compatible. See NEC articles 210.21, 630.11, and
630.12.
.Power cord supplied with unit is sized for 230 volt operation. Larger power cord may be required for cable length greater than 3 meters. Consult
national or local regulations.
300
50/60 Hz 3-Phase
380
50/60 Hz 3-Phase
Input Voltage (V) 220 400 220 400
Rated Maximum Supply Current I1max (A) 35.7 20.5 40 23
Maximum Effective Supply Current I1eff (A) 21.1 12.1 23.7 13.6
Max Recommended Standard Fuse Rating In Amperes1
Time-Delay Fuses2
Normal Operating Fuses3
40 25 50 25
50 30 60 30
Min Input Conductor Size In AWG (mm2)410 14 10 14
Max Recommended Input Conductor Length In Meters (Feet) 31
(102)
39
(127)
25
(82)
31
(101)
Min Grounding Conductor Size In AWG (mm2) 410 14 10 14
Reference: 2017 National Electrical Code (NEC) (including article 630)
1 If a circuit breaker is used in place of a fuse, choose a circuit breaker with time-current curves comparable to the recommended fuse.
2 “Time-Delay” fuses are UL class “RK5” . See UL 248.
3 “Normal Operating” (general purpose - no intentional delay) fuses are UL class “K5” (up to and including 60 amps), and UL class “H” ( 65 amps and
above).
4 Conductor data in this section specifies conductor size (excluding flexible cord or cable) between the panelboard and the equipment per NEC Table
310.15(B)(16) If a flexible cord or cable is used, minimum conductor size may increase. See NEC Table 400.5(A) for flexible cord and cable
requirements.
Notes