Miller XMT 450 CC User manual

Arc Welding Power Source
XMT 450 CC/CV
TM-257 220B 2015−03
Eff w/Serial Number MC100104A
Processes
Description
Multiprocess Welding
File: MULTIPROCESS
Visit our website at
www.MillerWelds.com
R
(400 Volt Model) CE

TABLE OF CONTENTS
SECTION 1 − SAFETY PRECAUTIONS FOR SERVICING 1........................................
1-1. Symbol Usage 1.......................................................................
1-2. Servicing Hazards 1....................................................................
1-3. California Proposition 65 Warnings 2......................................................
1-4. EMF Information 2.....................................................................
SECTION 2 − DEFINITIONS 3..................................................................
2-1. Additional Safety Symbols And Definitions 3................................................
2-2. Miscellaneous Symbols And Definitions 5..................................................
SECTION 3 − SPECIFICATIONS 6..............................................................
3-1. Features And Benefits 6................................................................
3-2. Arc Controls 6.........................................................................
3-3. Serial Number And Rating Label Location 6................................................
3-4. Unit Specifications 6....................................................................
3-5. Dimensions and Weight 7...............................................................
3-6. Environmental Specifications 7...........................................................
3-7. Duty Cycle and Overheating 8...........................................................
3-8. Volt-Ampere Curves 9..................................................................
SECTION 4 − INSTALLATION 10................................................................
4-1. Selecting a Location 10..................................................................
4-2. Weld Output Terminals And Selecting Cable Sizes* 11........................................
4-3. Connecting Weld Output Cables 12........................................................
4-4. Remote 14 Receptacle Information 12......................................................
4-5. 115 Volts AC Duplex Receptacle And Supplementary Protectors 13.............................
4-6. Optional Gas Valve Operation And Shielding Gas Connection 14...............................
4-7. Electrical Service Guide 15...............................................................
4-8. Connecting Input Power 16...............................................................
SECTION 5 − GENERAL OPERATION 18.........................................................
5-1. Front Panel 18..........................................................................
5-2. Mode Switch Settings 19.................................................................
SECTION 6 − GTAW OPERATION 20............................................................
6-1. Typical Connection For GTAW Process 20..................................................
6-2. Scratch Start TIG Welding Mode - GTAW Process 21.........................................
6-3. Lift-Arc TIG Welding Mode - GTAW Process 22..............................................
6-4. Remote Scratch Start TIG Welding Mode - GTAW Process 23..................................
SECTION 7 − GMAW/FCAW OPERATION 24......................................................
7-1. Typical Connection For Remote Control Feeder GMAW/FCAW Process 24.......................
7-2. MIG Welding Mode - GMAW/FCAW Process 25..............................................
7-3. Typical Connection For Remote Control Feeder GMAW-P Process 26...........................
7-4. Pulsed MIG Welding Mode - GMAW-P Process 27...........................................
7-5. Typical Connection For Voltage-Sensing Feeder GMAW/FCAW Process 28......................
7-6. V-Sense Feeder Welding Mode - GMAW/FCAW Process 29...................................
SECTION 8 − SMAW/CAC-A OPERATION 30.....................................................
8-1. Typical Connection For SMAW And CAC-A Process 30.......................................
8-2. Remote Stick Welding Mode - SMAW/CAC-A Process 31......................................
8-3. Stick Welding Mode - SMAW/CAC-A Process 32.............................................
8-4. Optional Low Open Circuit Voltage (OCV) Welding Modes 33..................................
8-5. Alternate Configuration Functions 33.......................................................
SECTION 9 − THEORY OF OPERATION 34.......................................................

TABLE OF CONTENTS
SECTION 10 − TROUBLESHOOTING 37.........................................................
10-1. Checking Unit Before Applying Power 37...................................................
10-2. Removing Case and Measuring Input Capacitor Voltage 38....................................
10-3. Input Rectifier SR1 39...................................................................
10-4. IGBT Modules PM1, PM2 40..............................................................
10-5. Interconnect Board PC2 41...............................................................
10-6. Output Diodes D1, D2, D3, D4 42..........................................................
10-7. Input Contactor W1 43...................................................................
10-8. Tank Capacitors C1, C2 43...............................................................
10-9. Troubleshooting Table 44.................................................................
10-10. Help Codes 45.......................................................................
10-11. Troubleshooting Circuit Diagram For Welding Power Source (All Models)
(Use With Section 10-12) 48...........................................................
10-12. Readings For Troubleshooting Circuit Diagram (All Models) (Use With Section 10-11) 50.........
10-13. Inverter Control Board PC1 Testing Information (Use With Section 10-14) 52...................
10-14. Inverter Control Boards PC1 Test Point Values 53.........................................
10-15. Inverter Control Board PC1 Diagnostic LEDs 54...........................................
10-16. Interconnect Board PC2 Testing Information (Use With Section 10-17) 56......................
10-17. Interconnect Board PC2 Test Point Values 57.............................................
10-18. Front Panel/Display Board PC3 Testing Information (Use with Section 10-19) 58................
10-19. Front Panel/Display Board PC3 Test Point Values 59.......................................
10-20. Checking Unit Output After Servicing 60.................................................
10-21. Enabling Low Open Circuit Voltage Welding Modes (Optional) 61.............................
10-22. Checking Bus Voltage Imbalance 62.....................................................
SECTION 11 − MAINTENANCE 63...............................................................
11-1. Routine Maintenance 63.................................................................
11-2. Blowing Out Inside Of Unit 63.............................................................
SECTION 12 − ELECTRICAL DIAGRAM 65.......................................................
SECTION 13 − PARTS LIST 74..................................................................

TM-257 220 Page 1XMT 450 CC/CV
SECTION 1 − SAFETY PRECAUTIONS FOR SERVICING
Protect yourself and others from injury — read, follow, and save these important safety precautions and operating instructions.
1-1. Symbol Usage
OM-257 220H, safety_stm 2013-09
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-
plainedin 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. Servicing 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.
Only qualified persons should test, maintain, and repair this
unit.
During servicing, keep everybody, especially children, away.
DDo not touch live electrical parts.
DTurn Off welding power source and wire feeder
and disconnect and lockout input power using
linedisconnect switch, circuit breakers, or by removing plug from re-
ceptacle,or stop engine before servicing unless the procedure spe-
cifically requires an energized unit.
ELECTRIC SHOCK can kill.
DInsulateyourself from ground by standing or working on dry insulat-
ing mats big enough to prevent contact with the ground.
DDo not leave live unit unattended.
DIf this procedure requires an energized unit, have only personnel
familiarwith and following standard safety practices do the job.
DWhentesting a live unit, use the one-hand method. Do not put both
hands inside unit. Keep one hand free.
DDisconnect input power conductors from deenergized supply line
BEFORE moving a welding power source.
SIGNIFICANT DC VOLTAGE exists in inverter weld-
ing power sources AFTER removal of input power.
DTurn Off inverter, disconnect input power, and discharge input
capacitorsaccording to instructions in Troubleshooting Section be-
fore touching any parts.
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.
FIRE OR EXPLOSION hazard.
DDo not place unit on, over, or near combustible
surfaces.
DDo not service unit near flammables.
FLYING METAL or DIRT can injure eyes.
DWear safety glasses with side shields or face
shield during servicing.
DBe careful not to short metal tools, parts, or
wires together during testing and servicing.
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, insulated welding gloves and
clothingto prevent burns.
EXPLODING PARTS can injure.
DFailedparts can explode or cause other parts to
explodewhen power is applied to inverters.
DAlways wear a face shield and long sleeves
when servicing inverters.
SHOCK HAZARD from testing.
DTurn Off welding power source and wire feeder
or stop engine before making or changing me-
ter lead connections.
DUse at least one meter lead that has a self-
retainingspring clip such as an alligator clip.
DRead instructions for test equipment.
FALLING EQUIPMENT can injure.
DUse lifting eye to lift unit only, NOT running
gear, gas cylinders, or any other accessories.
DUse equipment of adequate capacity to lift and
supportunit.
DIf using lift forks to move unit, be sure forks are long enough to
extend beyond opposite side of unit.
DFollowthe guidelines in the Applications Manual for the Revised
NIOSH Lifting Equation (Publication No. 94−110) when manu-
ally lifting heavy parts or equipment.

TM-257 220 Page 2 XMT 450 CC/CV
MOVING PARTS can injure.
DKeep away from moving parts such as fans.
DKeep away from pinch points such as drive
rolls.
DHave only qualified persons remove doors,
panels,covers, or guards for maintenance and
troubleshootingas necessary.
DKeep hands, hair, loose clothing, and tools
away from moving parts.
DReinstall doors, panels, covers, or guards
when maintenance is finished and before re-
connectinginput power.
ELECTRIC AND MAGNETIC FIELDS (EMF)
can affect Implanted Medical Devices.
DWearers of Pacemakers and other Implanted
MedicalDevices should keep away from serv-
icing areas until consulting their doctor and the
device manufacturer.
OVERUSE can cause OVERHEATING.
DAllow cooling period; follow rated duty cycle.
DReduce current or reduce duty cycle before
startingto weld again.
DDo not block or filter airflow to unit.
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
electronicequipment install, test, and service
H.F. producing units.
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
equipmentat once.
DHave the installation regularly checked and maintained.
DKeephigh-frequency source doors and panels tightly shut, keep
spark gaps at correct setting, and use grounding and shielding to
minimizethe possibility of interference.
READ INSTRUCTIONS.
DUse Testing Booklet (Part No. 150 853) when
servicing this unit.
DConsultthe Owner’s Manual for welding safety
precautions.
DUse only genuine replacement parts from the manufacturer.
DReadand follow all labels and the TechnicalManual carefully be-
fore installing, operating, or servicing unit. Read the safety in-
formationat the beginning of the manual and in each section.
DPerform maintenance and service according to the Technical
Manual,industry standards, and national, state, and local codes.
1-3. California Proposition 65 Warnings
Welding or cutting equipment produces fumes or gases
which contain chemicals known to the State of California to
cause birth defects and, in some cases, cancer. (California
Health & Safety Code Section 25249.5 et seq.)
This product contains chemicals, including lead, known to
the state of California to cause cancer, birth defects, or other
reproductiveharm. Wash hands after use.
1-4. 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
inductionheating operations) creates an EMF field around the welding
circuit. EMF fields may 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.

TM-257 220 Page 3XMT 450 CC/CV
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 2012−05
Wear dry insulating gloves. Do not touch electrode with bare hand. Do not wear wet or damaged gloves.
Safe2 2012−05
Protect yourself from electric shock by insulating yourself from work and ground.
Safe3 2012−05
Disconnectinput plug or power before working on machine.
Safe5 2012−05
Keep your head out of the fumes.
Safe6 2012−05
Use forced ventilation or local exhaust to remove the fumes.
Safe8 2012−05
Use ventilating fan to remove fumes.
Safe10 2012−05
Keepflammables away from welding. Do not weld near flammables.
Safe12 2012−05
Weldingsparks can cause fires. Have a fire extinguisher nearby, and have a watchperson ready to use it.
Safe14 2012−05

TM-257 220 Page 4 XMT 450 CC/CV
Do not weld on drums or any closed containers.
Safe16 2012−05
Do not remove or paint over (cover) the label.
Safe20 2012−05
Disconnectinput plug or power before working on machine.
Safe30 2012−05
Flying pieces of parts can cause injury. Always wear a face shield when servicing unit.
Safe27 2012−05
Always wear long sleeves and button your collar when servicing unit.
Safe28 2012−05
After taking proper precautions as shown, connect power to unit.
Safe29 2012−05
Do not use one handle to lift or support unit.
Safe31 2012−05
?V
?AConsultrating label for input power requirements.
Safe34 2012−05
Becometrained and read the instructions before working on machine.
Safe35 2012−05
Connect Green Or Green/Yellow grounding conductor to ground terminal first.
Connect input conductors (L1, L2, L3) to line terminals.
Safe36 2012−05

TM-257 220 Page 5XMT 450 CC/CV
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 Becometrained and read the instructions before working on the
machine or welding.
Safe40 2012−05
>5min
V
V
V
Hazardous voltage remains on input capacitors after power is turned
off. Do not touch fully charged capacitors. Always wait 5 minutes after
power is turned off before working on unit, OR check input capacitor
voltage, and be sure it is near 0 before touching any parts.
Safe43 2012−05
=<60°Always lift and support unit using both handles. Keep angle of lifting
device less than 60 degrees.
Use a proper cart to move unit.
Safe44 2012−05
2-2. Miscellaneous Symbols And Definitions
AAmperage
Output
Off
Direct Current
(DC)
Constant Current
Arc Force
U
0Rated No Load
Voltage (OCV)
Hz Hertz
Pulsed
I
1max Rated Maximum
Supply Current
Panel
Alternating
Current (AC)
VVoltage
On
Voltage Input
Protective Earth
(Ground)
Line Connection
Three Phase
Static Frequency
Converter-
Transformer-
Rectifier
XDuty Cycle
%
Percent
Three Phase
Lift-Arc Operation
(GTAW)
Remote
Negative
Inductance
Foot Control
Gas Metal Arc
Welding (GMAW)
U2Conventional
Load Voltage
I
2Rated Welding
Current
Single Phase
Increase
Circuit Breaker
Gas Tungsten Arc
Welding
Positive
Constant Voltage
Shielded Metal
Arc Welding
(SMAW)
U
1Primary Voltage
IP
Degree Of
Protection
Lift-Arc Trigger
Hold Operation
(GTAW)
I
1eff Maximum Effec-
tive Supply Cur-
rent

TM-257 220 Page 6 XMT 450 CC/CV
SECTION 3 − SPECIFICATIONS
3-1. Features And Benefits
LVCtLine Voltage Compensation is circuitry that keeps the power source output constant regardless of input pow-
er fluctuation.
Wind Tunnel Technologytcirculates air over components that require cooling, not over electronic circuitry, which
reduces contaminants and improves reliability in harsh welding environments.
Fan-On-Demandtcooling system operates only when needed, reducing noise, energy use and the amount of con-
taminants pulled through the machine.
Thermal Overload Protection automatically shuts down the unit, only when necessary to prevent damage to internal
components if the duty cycle is exceeded or air flow and cooling are restricted (see Section 3-7).
Auto Remote Sense enables the unit to automatically sense the connection of a remote control. Operation of the
remote control is dependent on the Mode Switch Setting (see Section 5-2).
Lift-ArctTIG starts provide a contamination free weld without the use of high frequency in the Lift-Arc TIG Welding
Mode (see Section 6-3).
Adaptive Hot Starttfor Stick increases the output amperage at the start of a weld, eliminating electrode sticking
in CC and Stick Welding Modes (see Sections 8-2 and 8-3).
3-2. Arc Controls
DIG control allows the arc characteristics, soft versus stiff, to be changed for specific applications and electrodes in
CC and Stick Welding Modes (see Sections 8-2 and 8-3).
Inductance influences the arc stiffness, bead width and appearance, and puddle fluidity in MIG and V-Sense Feeder
Welding Modes (see Sections 7-2 and 7-6).
3-3. Serial Number And Rating Label Location
The serial number and rating information for this product is located on the rear panel. 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.
3-4. Unit Specifications
.Do not use information in unit specifications table to determine electrical service requirements. See Sections 4-7 and 4-8 for information on con-
nectinginput power.
Input
Power Rated Welding Output
Amperag
e
Range Voltage
Range
Maximum
Open-
Circuit
Voltage DC
Amperes Input
At Rated Load
Output 50/60 Hz,
Three-Phase
KVA KW
380V 400V 380V 400V 380V 400V
Three
Phase 450 A @ 38 Volts DC, 100% Duty Cycle 15 − 600 10 − 38 90 32.6 (0.42*) 32.1 (0.47*) 21.5 (0.28*) 22.3 (0.32*) 19.1 (0.07*) 19.2 (0.07*)
*While idling with fan on
Notes

TM-257 220 Page 7
XMT 450 CC/CV
3-5. Dimensions and Weight
Hole Layout Dimensions
C
D
AG
14.5 in.
(368 mm)
26.8 in.
(681 mm)
17.2 in.
(437 mm)
BRef. 252 018-A
F
E
A 8-11/16 in. (221 mm)
B11-3/8 in. (289 mm)
C15-3/4 in. (400 mm)
D22-7/16 in. (570 mm)
E2-3/4 in. (70 mm)
F3-3/8 in. (86 mm) Dia.
G1/4-20 UNC 2B Thread
Weight
122 lb (55.3 kg)
3-6. Environmental Specifications
A. IP Rating
IP Rating
IP23
This equipment is designed for outdoor use. It may be stored, but is not intended to be used
for welding outside during precipitation unless sheltered.
IP23 2014−06
B. Information On Electromagnetic Fields (EMF)
!This equipment shall not be used by the general public as the EMF limits for the general public might be exceeded during welding.
This equipment is built in accordance with EN 60974−1 and is intended to be used only in an occupational environment (where the general public
access is prohibited or regulated in such a way as to be similar to occupational use) by an expert or an instructed person.
Wire feeders and ancillary equipment (such as torches, liquid cooling systems and arc striking and stabilizing devices) as part of the welding
circuit may not be a major contributor to the EMF. See the Owner’s Manuals for all components of the welding circuit for additional EMF exposure
information.
SThe EMF assessment on this equipment was conducted at 0.5 meter.
SAt a distance of 1 meter the EMF exposure values were less than 20% of the permissible values. ce-emf 1 2010-10
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−
voltagesupply 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 73.66 mW(or the short−circuit power Ssc is greater than
2,172,158VA). 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

TM-257 220 Page 8 XMT 450 CC/CV
3-7. Duty Cycle and Overheating
Duty Cycle is percentage of 10 min-
utes that unit can weld at rated load
withoutoverheating.
If unit overheats, thermostat(s)
opens, output stops, and cooling
fan runs. Wait fifteen minutes for
unit to cool. Reduce amperage or
duty cycle before welding.
NOTICE − Exceeding duty cycle
can damage unit and void warranty.
Overheating 0
15
A/V
OR
Reduce Duty Cycle
Minutes
duty1 4/95 − SA-181 560 / 250 541-A
ContinuousWelding
100% Duty Cycle At 450 Amperes 60% Duty Cycle At 580 Amperes
6 Minutes Welding 4 Minutes Resting

TM-257 220 Page 9
XMT 450 CC/CV
3-8. Volt-Ampere Curves
Volt-ampere curves show minimum
and maximum voltage and amper-
age output capabilities of welding
power source. Curves of other set-
tings fall between curves shown.
AMPERAGE
VOLTAGE
CC Mode
VOLTAGE
CV MODE
AMPERAGE
0
20
40
60
80
100
0 100 200 300 400 500 600 700
MAX
MIN
252 918-A / 252 919-A
0
20
40
60
80
100
0 100 200 300 400 500 600
10
30
50
70
90
TIG
REMOTE
TIG
SCRATCH
TIG
MAX
STICK
MAX
STICK
80A
TIG
MIN 100%
0%25% 50%75%
ARC CONTROL (DIG)

TM-257 220 Page 10 XMT 450 CC/CV
SECTION 4 − INSTALLATION
4-1. Selecting a Location
Ref. ST-151 556 / 800 611 / Ref. 250 026-B
!Special installation may be
required where gasoline or
volatileliquids are present −
see NEC Article 511 or CEC
Section20.
1 Lifting Forks
Use lifting forks to move unit.
Extend forks beyond opposite side
of unit.
2 Lifting Handles
Use handles to lift unit.
3 Hand Cart
Use cart or similar device to move
unit.
4 Line Disconnect Device
Locate unit near correct input
power supply.
Movement 2
3
Location
4
18 in.
(460 mm)
18 in.
(460 mm)
Tipping
1
OR
!Do not move or operate
unit where it could tip.
Notes

TM-257 220 Page 11
XMT 450 CC/CV
4-2. Weld Output Terminals And Selecting Cable Sizes*
NOTICE − The Total Cable Length in Weld Circuit (see table below) is the combined length of both weld cables. For example, if the power source is
100 ft (30 m) from the workpiece, the total cable length in the weld circuit is 200 ft (2 cables x 100 ft). Use the 200 ft (60 m) column to determine cable
size.
!Turn off power be-
fore connecting to
weld output termi-
nals.
!Do not use worn,
damaged, under-
sized, or repaired
cables.
Weld Output
Terminals
Weld Cable Size** and Total Cable (Copper) Length in Weld Circuit
Not Exceeding***
100 ft (30 m) or Less 150 ft
(45 m) 200 ft (60 m) 250 ft (70 m) 300 ft (90 m) 350 ft (105 m) 400 ft (120 m)
Welding
Amperes
10 − 60%
Duty
Cycle
AWG (mm2)
60 − 100%
Duty
Cycle
AWG (mm2)
10 − 100% Duty Cycle
AWG (mm2)
Positive
(+) Negative
(−)
100 4 (20) 4 (20) 4 (20) 3 (30) 2 (35) 1 (50) 1/0 (60) 1/0 (60)
150 3 (30) 3 (30) 2 (35) 1 (50) 1/0 (60) 2/0 (70) 3/0 (95) 3/0 (95)
200 3 (30) 2 (35) 1 (50) 1/0 (60) 2/0 (70) 3/0 (95) 4/0 (120) 4/0 (120)
250 2 (35) 1 (50) 1/0 (60) 2/0 (70) 3/0 (95) 4/0 (120) 2x2/0
(2x70) 2x2/0 (2x70)
300 1 (50) 1/0 (60) 2/0 (70) 3/0 (95) 4/0 (120) 2x2/0
(2x70) 2x3/0 (2x95) 2x3/0 (2x95)
350 1/0 (60) 2/0 (70) 3/0 (95) 4/0 (120) 2x2/0
(2x70) 2x3/0 (2x95) 2x3/0 (2x95) 2x4/0 (2x120)
400 1/0 (60) 2/0 (70) 3/0 (95) 4/0 (120) 2x2/0
(2x70) 2x3/0 (2x95) 2x4/0 (2x120) 2x4/0 (2x120)
500 2/0 (70) 3/0 (95) 4/0 (120) 2x2/0
(2x70) 2x3/0 (2x95) 2x4/0 (2x120) 3x3/0 (3x95) 3x3/0 (3x95)
600 3/0 (95) 4/0 (120) 2x2/0
(2x70) 2x3/0 (2x95) 2x4/0 (2x120) 3x3/0 (3x95) 3x4/0 (3x120) 3x4/0 (3x120)
* This chart is a general guideline and may not suit all applications. If cable overheats, use next size larger cable.
**Weld cable size (AWG) is based on either a 4 volts or less drop or a current density of at least 300 circular mils per ampere.
( ) = mm2for metric use
***For distances longer than those shown in this guide, call a factory applications rep. at 920-735-4505 (Miller) or 1-800-332-3281 (Hobart).
Ref. S-0007-K 2013−10

TM-257 220 Page 12 XMT 450 CC/CV
4-3. Connecting Weld Output Cables
803 778-B
!Turn off power before connecting to
weld output terminals.
!Failure to properly connect weld
cables may cause excessive heat
and start a fire, or damage your ma-
chine.
1 Weld Output Terminal
2 Supplied Weld Output Terminal Nut
3 Weld Cable Terminal
4 Copper Bar
Remove supplied nut from weld output ter-
minal.Slide weld cable terminal onto weld
outputterminal and secure with nut so that
weld cable terminal is tight against copper
bar.Do not place anything between weld
cable terminal and copper bar. Make
sure that the surfaces of the weld cable
terminal and copper bar are clean.
Tools Needed:
3/4 in. (19 mm)
4
2
3
Do not place
anything between
Incorrect Installation
1
weld cable terminal
and copper bar.
4-4. Remote 14 Receptacle Information
AJ
BKI
CLNH
DMG
EF
Ref. 252 018-A
Socket* Socket Information
24 VOLTS AC A24 volts AC. Protected by supplementary protect-
or CB2.
BContact closure to A completes 24 volts AC con-
tactor control circuit.
REMOTE
CONTROL
COutput to remote control; +10 volts DC in MIG
mode. 0 to +10 volts DC in other modes.
DRemote control circuit common.
E0 to +10 volts DC input command signal from re-
mote control.
MCC/CV select 0 to +10 volts DC.
A/V
AMPERAGE
VOLTAGE
FCurrent feedback; +1 volt DC per 100 amperes.
HVoltage feedback; +1 volt DC per 10 arc volts.
GND GCircuit common for 24 volt AC circuit.
KChassis common.
*The remaining sockets are not used.

TM-257 220 Page 13
XMT 450 CC/CV
4-5. 115 Volts AC Duplex Receptacle And Supplementary Protectors
Ref. 257 348-A
1 115 V 7 Amp AC Receptacle
2 Supplementary Protector CB1
3 Supplementary Protector CB2
CB1 protects duplex receptacle.
CB2 protects 24 volts AC portion of
Remote 14 receptacle from
overload.
Press button to reset supplement-
ary protector.
23
1
Notes

TM-257 220 Page 14 XMT 450 CC/CV
4-6. Optional Gas Valve Operation And Shielding Gas Connection
Ref. 252 021-A / 257 348-A
Obtain gas cylinder and chain to
runninggear, wall, or other station-
ary support so cylinder cannot fall
and break off valve.
1 Cylinder
2 Regulator/Flowmeter
Install so face is vertical.
3 Gas Hose Connection
Fitting has 5/8-18 right-hand
threads. Obtain and install gas
hose.
4 Gas In Fitting
5 Gas Out Fitting
The Gas In and Gas Out fittings
have 5/8-18 right-hand threads.
Obtainproper size, type, and length
hose and make connections as fol-
lows:
Connect hose from shielding gas
supply regulator/flowmeter to Gas
In fitting.
Connect hose coupler to torch.
Connect one end of gas hose to
hose coupler. Connect remaining
end of gas hose to Gas Out fitting.
Operation
The gas solenoid controls gas flow
during the TIG process as follows:
Remote TIG
Gas flow starts with remote contac-
tor on.
Gas flow stops at end of post−flow
if current was detected, or with re-
motecontactor off if no current was
detected.
Lift−Arc TIG
Gas flow starts when tungsten
touches work (touch sensed).
Gas flow stops at end of post−flow.
Scratch Start TIG
Gas flow starts when current is de-
tected.
Gas flow stops at end of post−flow.
Post−flow time is factory set to 4
seconds per 100 amps of weld cur-
rent. The minimum post−flow time
is 5 seconds. The maximum post−
flow is 24 seconds (post flow set-
tings are not adjustable by the end
user).
4
3
1
2
GAS IN
GAS OUT
5

TM-257 220 Page 15
XMT 450 CC/CV
4-7. Electrical Service Guide
Elec Serv 2014−01
NOTICE − INCORRECT INPUT POWER can damage this welding power source. This welding power source requires a CONTINUOUS supply of
inputpower at rated frequency(+10%) and voltage (+10%).Phase to ground voltage shall not exceed +10% of rated input voltage. Do not use a genera-
tor with automatic idle device (that idles engine when no load is sensed) to supply input power to this welding power source.
NOTICE − Actual input voltage should not be 10% less than minimum and/or 10% more than maximum input voltages listed in table. If actual input
voltage is outside this range, output may not be be available.
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.
50/60 Hz Three Phase
Input Voltage (V) 380 400
Input Amperes (A) At Rated Output 32.6 32.1
Max Recommended Standard Fuse Rating In Amperes 1
Time-Delay Fuses 240 35
Normal Operating Fuses 350 45
Min Input Conductor Size In AWG 48 8
Max Recommended Input Conductor Length In Feet (Meters) 279
(85) 309 (94)
Min Grounding Conductor Size In AWG 410 10
Reference: 2014 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 “NormalOperating” (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

TM-257 220 Page 16 XMT 450 CC/CV
4-8. Connecting Input Power
Tools Needed:
5/16 in.
3
8
1
4
9
7
10
11
L1
L2
L3
= GND/PE Earth Ground
1
Input5 2013−04 / Ref. 803 766-C / 257 348-A
2
4
3
6
5
7
L1
L2
L3