
XMT®350/450 Series
Multiprocess Welding
Power Source
Issued July 2012 • Index No. DC/18.83
Lightweight, aerospace-grade aluminum case
offers protection with the benefit of reduced weight.
Lift-Arc™allows TIG starting without the use of
high-frequency. Starts the arc without contaminating
the weld with tungsten.
Adaptive Hot Start
™
increases the output amperage
at the start of a weld if necessary, eliminating
electrode sticking.
Inverter arc control technology provides greater
puddle control for superior 6010 Stick electrode
performance, and outstanding MIG weld performance.
Fan-On-Demand
™
cooling system operates only
when needed, reducing noise, energy use and the
amount of contaminants pulled through machine.
The Power of Blue®.
Wind Tunnel Technology™protects electrical
components and PC boards from contamination.
Processes
MIG (GMAW)/Pulsed MIG (GMAW-P)*
Stick (SMAW)
TIG (GTAW)
Flux-Cored (FCAW)
Air Carbon Arc Cutting and Gouging (CAC-A)
*XMT 350 CC/CV and 450 CC/CV with
required optional control; not available with
XMT 350 VS model.
Input Power 350: Requires 3- or 1-Phase Power,
450: Requires 3-Phase Power
Rated Output 350: 10– 38 V, 15– 425 A
450: 10 – 38 V, 15– 600 A
Net Weight 350: 80 lb. (36.3 kg)
450: 122 lb. (55.3 kg)
Heavy Industrial Applications
Construction
Shipbuilding
Railroad
Truck/Trailer Manufacturing
Fabrication
Repair Shops
Rental Fleets
Power Generation Plants
Power source is warranted for 3 years, parts and labor.
Original main power rectified parts are warranted for 5 years.
Gun warranted for 90 days, parts and labor.
Quick
Specs
XMT 350 CC/CV
XMT 450 CC/CV
XMT 350 VS
Line voltage compensation keeps welding output
constant even if input power varies by +/-10 percent.
Line voltage compensation further expands to an
amazing +37/-59 percent when operating on 460 VAC.
Process selector switch reduces the number of
control setup combi nations without reducing
any features.
Large, dual digital meters are easy to view and are
presettable to ease setting weld output.
XMT 350 Model Only
Auto-Line
™
Power Management
Technology allows for any input
voltage hook-up (208 – 575 V) with
no manual linking required, providing
convenience in any job setting. Ideal
solution for dirty or unreliable input
power. (450 model is manual link.)
Dinse- or Tweco-style weld
disconnects provide high-quality
weld cable connections. (450 model
utilizes studs.)
Miller Electric Mfg. Co.
An Illinois Tool Works Company
1635 West Spencer Street
Appleton, WI 54914 USA
Website
MillerWelds.com
Equipment Sales US and Canada
Phone: 866-931-9730
FAX: 800-637-2315
International Phone: 920-735-4554
International FAX: 920-735-4125

XMT®350/450 Performance Data
Model
XMT
350
CC/CV
and VS
XMT
450
CC/CV
Input
Power
ThreePhase
SinglePhase
ThreePhase
Rated Out put
350 A at 34 VDC,
60% Duty Cycle
300 A at 32 VDC,
60% Duty Cycle
450 A at 38 VDC,
100% Duty Cycle
Amperage
Range in
CC Mode
5–425 A
5–425 A
15–600 A
Voltage
Range in
CV Mode
10–38 V
10–38 V
10–38 V
Max. OpenCircuit
Voltage
75 VDC
75 VDC
90 VDC
Amps Input at Rated Load Output, 60 Hz
208 V 230 V 400 V 460 V 575 V KVA KW
40.4 36.1 20.6 17.8 14.1 14.2 13.6
60.8 54.6 29.7 24.5 19.9 11.7 11.2
— 51 32.1 27.6 24.4 22 18.9
Weight
80 lb.
(36.3 kg)
122 lb.
(55.3 kg)
Dimensions
H: 17 in. (432 mm)
W: 12.5 in. (318 mm)
D: 24 in. (610 mm)
H: 17.25 in. (438 mm)
W: 14.5 in. (368 mm)
D: 27.125 in. (689 mm)
XMT®350/450 Specifications
(Subject to change without notice.)
(XMT 450 CC/CV
is 3-Phase only.)
Certified by Canadian Standards Association to both the Canadian and U.S. Standards.
500
425
400
350
300
250
200
WELDING AMPERES
150
XMT 350 CC/CV and VS DUTY CYCLE CHART
3-PHASE OPERATION
1-PHASE OPERATION
6 AWG POWER CORD
8 AWG POWER CORD
100
10 15 20 25
30
% DUTY CYCLE
XMT 450 CC/CV DUTY CYCLE CHART
700
600
500
400
300
200
WELDING AMPERES
150
100
10 15 20 25 30 40 6050 70 80 90 100
3-PHASE OPERATION
% DUTY CYCLE
56%
10040 50 60 70 9080

3
1. Voltmeter
2. Remote Control Receptacle
3. Process Selector Switch (Rotary Switch)
4. Optional Gas Valve
5. Ammeter
6. Voltage/Amperage Adjustment Control
7. Arc Control (FCAW Setting for
Flux-Cored Welding)
8. Power On/Off Switch
XMT®350 VS Control Panel
XMT®350 CC/CV Control Panel
Additional Features
Low OCV Stick. A built-in, selectable
feature, that reduces the Stick mode
open-circuit voltage (OCV) to nearly
15 volts when the welding power source
is not in use. Eliminates the need for
add-on voltage reducers.
Note: VS model is available only with
Tweco-style weld cable disconnects. Tweco
cable connectors are not supplied with the
unit and must be ordered separately.
Optional 115 VAC auxiliary power is not
available on VS model.
Pulsed MIG (GMAW-P) capability is not
available on VS model.
Additional Features
Auto Remote Sense™enables unit to
automatically use remote control if
connected to remote control receptacle.
Low OCV Stick. A built-in, selectable
feature, that reduces the Stick mode
open-circuit voltage (OCV) to nearly
15 volts when the welding power source
is not in use. Eliminates the need for
add-on voltage reducers.
Dinse- or Tweco-style weld disconnects
provide high-quality weld cable connections.
Optional 115-VAC auxiliary power provides
10 amps of circuit-breaker-protected power
for water circulators, etc.
Pulsed MIG (GMAW-P) capabilities with
optional Optima
™
control reduces spatter
and distortion, allows better out-of-position
puddle control, and provides potential
reduction of fume particle emission.
1. Voltmeter
2. Process Selector Switch (Rotary Switch)
3. Optional Gas Valve
4. Ammeter
5. Voltage/Amperage Adjustment Control
6. Arc Control (FCAW Setting for
Flux-Cored Welding)
7. Power On/Off Switch
Note: VS model is equipped with Tweco-style
output connector.
Manufactured Under the
Following US Patents:
5,601,741 5,642,260 5,902,150
6,002,103 6,115,273 6,193,548
6,239,407 6,266,257 6,625,046
6,611,189 6,426,888
Other Patents Pending
1
2
3
4
5
6
7
Manufactured Under the
Following US Patents:
5,601,741 5,642,260 5,902,150
6,002,103 6,115,273 6,193,548
6,239,407 6,266,257 6,625,046
6,611,189 6,426,888
Other Patents Pending
1
2
3
4
5
6
CC
7
FCAW
8

4
XMT®350 Wire Feeder Packages
XMT®350 CC/CV, 22A, MIGRunner™#951 327
XMT®350 CC/CV S-74D MIGRunner™#951 314 (not shown)
Comes complete with:
XMT 350 CC/CV power
source
22A or S-74D wire feeder
Bernard
®
Q™-Gun
Consumables
.035/.045-in. drive roll kit
Regulator/flow gauge with
gas hose
MIGRunner Cart with
cylinder rack
Bottom tray will hold optional
Coolmate
™
3 (sold separately)
XMT®450 CC/CV Control Panel
Additional Features
Primary voltage display shows what
primary voltage the power source is
linked for without removing the side
panels. Saves time and assures you that
the power source has been correctly
linked for available input voltage.
Unique case design helps protect
internal components from dirt and dust.
To connect input power cord and/or set
unit up for correct input power, remove
the easy-to-handle panel (1/3 case). The
remaining two-thirds of the case never
needs to be removed!
1. Voltmeter
2. Remote Control Receptacle
3. Process Selector Switch (Rotary Switch)
4. Ammeter
5. Voltage/Amperage Adjustment Control
6. Power On/Off Switch
7. Arc Control
8. Optional Gas Valve
Note : 450 model is equipped with studs for
ring-lug output connections.
SuitCase®X-TREME™8VS with XMT®350 VS and
Bernard®Q300 gun #951 306
Pulse Stick Remote Feeder Weight
MIG MIG Control Remote w/steel
TIG Cable Control wire
No Yes No No 32 lb.
SuitCase®X-TREME™12VS with XMT®350 CC/CV
and Bernard®Q300 gun #951 305
Pulse Stick Remote Feeder Weight
MIG MIG Control Remote w/steel
TIG Cable Control wire
No Yes No No 66 lb.
1
2
3
4
5
6
7
8

5
Optima™#043 389
A multipurpose,
microprocessor-based
pulse control for both
synergic MIG (wire
welding or GMAW) or
manual MIG pulsing.
Use this control with the
XMT CC/CV power
sources and any Miller wire feeder, including
automatic feeders and spool guns. Includes
a 25-foot (7.6 m) cord with 14-pin plug.
(Not for use with XMT VS model.)
Extension Cords for Optima
#242 205 025 25 ft. (7.6 m)
#242 205 050 50 ft. (15 m)
#242 205 080 80 ft. (24.3 m)
WC-24 Weld Control
#137 549
Designed for use
with Miller CV power
sources supplying
24 VAC and 14-pin
receptacles. For use
with Spoolmatic 30A
spool gun.
HF-251D-1 High-Frequency Arc Starter
and Stabilizer #042 388
Portable 250-amp, 60-percent duty cycle
unit adds high frequency to the welding
circuit to help start the arc when using the
DC TIG (GTAW) process. Operates on 115
VAC, 50/60 Hz. See Lit. Index No. AY/5.1.
Wireless Remote Foot Control #300 429
For remote current and contactor control.
Receiver plugs directly into the 14-pin
receptacle of Miller machine. 90-foot
(27.4 m) operating range.
Wireless Remote
Hand Control
#300 430
For remote current
and contactor control.
Receiver plugs directly
into the 14-pin receptacle of Miller machine.
300-foot (91.4 m) operating range.
RFCS-14 Foot Control
#043 554
Foot current and
contactor control.
Includes 20-foot (6 m)
cord and 14-pin plug.
RHC-14 Hand Control*
#242 211 020
20-foot (6 m) cord
#242 211 100
100-foot (30.5 m) cord
Miniature hand control for remote current
and contactor control. Dimensions: 4 x 4 x
3.25 inches (102 x 102 x 82 mm). Includes
cord and 14-pin plug.
*Custom lengths available in 5-foot increments up to
50 feet and 10-foot increments up to 100 feet.
RMLS-14 #129 337 14-pin plug
Momentary- and maintained-contact rocker
switch for contactor control. Push forward for
maintained contact and back for momentary
contact. Includes 20-foot (6 m) cord.
RCC-14 Remote Contactor and Current
Control #151 086 14-pin plug
Rotary-motion fingertip control fastens to
TIG torch using two Velcro
®
straps.
Includes 26.5 foot (8 m) control cord.
RCCS-14 Remote Contactor and Current
Control #043 688 14-pin plug
Up-and-down rotary-motion fingertip
control. Great for applications that require
a finer amperage control. Includes 26.5-foot
(8 m) control cord.
Extension Cables for Remote Controls
and 24 VAC Wire Feeders*
#242 208 025 25 ft. (7.6 m)
#242 208 050 50 ft. (15 m)
#242 208 080 80 ft. (24.3 m)
14-pin plug to 14-pin socket. Not for use
with Optima or XR-AlumaFeed feeder.
*Custom lengths available in 5-foot increments up to
50 feet and 10-foot increments up to 100 feet.
Running Gear
MIGRunner™Cart #195 445
Running Gear Cylinder Rack
#300 408 For dual feeders
Small footprint and easily maneuverable,
with cylinder rack low enough that you do
not have to lift bottles.
XMT Cylinder Cart
#042 537
Carries two
160-pound
(72.6 kg) gas
cylinders, or one
gas cylinder and
one coolant
system for TIG
(GTAW) welding. Feeder mounts to tray
above power source.
Universal Carrying
Cart and Cylinder
Rack #042 934
Holds power
source, and
gas cylinder
up to 56 inches
(142.2 cm) high measuring 6 to 9 inches
(15.2 to 22.8 cm) in diameter.
Genuine Miller®Accessories
#300 408
#195 445

Protective Cover
#195 478
Mildew and water
resistant, odor-free
cover protects your
machine’s finish.
For 300/350 A
inverters: XMT,
Maxstar and
Dynasty.
Inverter Racks
Four or Six-Arc Welding System
The Inverter Rack conve niently houses
multiple XMT power sources for multiple
welders. Both 4-pack and 6-pack models
are available.
Features include:
Provision to parallel power sources or
common work connections
Two lifting eyes for transportation
Rugged skids for dragging or pushing
Customer can install up to a maximum
of four XMT 450 CC/CV power sources
For detailed information on customized
Inverter Rack systems see Lit. Index No.
DC/18.81.
Wire Feeders/Guns
SuitCase®X-TREME™8VS #951 181
SuitCase®X-TREME™12VS #951 184
Lightweight, portable wire feeder for a
variety of wires up to .062 inch. Holds up
to an 8-inch (8VS) or 12-inch (12VS) spool
of wire. Operates on open-circuit voltage
eliminating the need for a control/power
cord. See Lit. Index No. M/6.41.
SuitCase®8RC #951 186
SuitCase®12RC #951 188
Lightweight, portable wire feeder for a
variety of wires up to .062 inch. Holds up
to an 8-inch (8RC) or 12-inch (12RC) spool
of wire. Operates using 14-pin control
receptacle. See Lit. Index No. M/6.5.
XR™-S Control #300 601
XR™-D Control #300 678
The updated XR Controls offer unsurpassed
performance and reliability for feeding
aluminum and other difficult-to-feed wire
types. Models include .035-inch and
factory-installed 3/64-inch drive rolls. See
Lit. Index No. M/1.7.
XR-AlumaFeed
™
#300 509
Advanced push-pull wire
feeder designed for highvolume, high-production
aluminum MIG welding
where quality and consistency is a high
priority. See Lit. Index No. DC/34.
70 Series
S-74S #951 196
S-74D #951 198
S-74DX #951 200
Features Posifeed
™
wire drive assembly
and handles a variety of wires up to 1/8 inch.
Comes with FREE Bernard®Q™-Gun. Dualwire models also available. See Lit. Index
No. M/3.0.
Extension Cables*
#247 831 025 25 ft. (7.6 m)
#247 831 050 50 ft. (15.2 m)
#247 831 080 80 ft. (24.4 m)
Eleven conductors to support contactor
control and remote voltage control on all
Miller electronic CV 14-pin power sources.
*Custom lengths available in 5-foot increments up to
50 feet and 10-foot increments up to 100 feet.
Spoolmatic®30A #130 831
A one-pound, air-cooled spool gun that
extends the weld process range by adding
a handy portable system for small wire
MIG. Rated 200 amps at 100% duty cycle.
Includes 30-foot (9.1 m) cable assembly.
WC-24 (#137 549) required for use with
14-pin receptacles, order separately.
Ironmate
™
Flux Cored Guns
See Lit. Index No. AY/16.0.
FC-1260
#195 732 10 ft. (3 m)
#195 729 15 ft. (4.6 m)
FC-1260LM
#194 912 10 ft. (3 m)
#194 911 15 ft. (4.6 m)
FC-1150
#194 864 10 ft. (3 m)
#194 863 15 ft. (4.6 m)
6
Genuine Miller®Accessories
(continued)

Genuine Miller®Accessories
(continued)
7
Coolmate™3
#043 007 115 VAC
#043 008 230 VAC
For use with water-cooled torches rated up
to 600 amps. Unique paddle-wheel indicator,
external filter and easy-fill spout.
Coolmate
™
V3 #043 009 115 VAC
For use with water-cooled torches rated up
to 500 amps. Vertical design conveniently
mounts to Miller cylinder rack in place of
one cylinder.
Coolmate
™
4 #042 288 115 VAC
For use with water-cooled torches rated up
to 600 amps. Tough molded polyethylene
case with carrying handle.
Coolant #043 810
Sold in cases of four one-gallon recyclable
plastic bottles. Miller coolants contain a base
of ethylene glycol and deionized water to
protect against freezing to -37 degrees
Fahrenheit (-38° C) or boiling to 227 degrees
Fahrenheit (108° C). Also contains a
compound that resists algae growth.
Cable Connectors and Adapters
Note: XMT 350 power sources are equipped with
Dinse- or Tweco-style connectors for secondary
connections.
Dinse-Style Connectors
#042 418
Accepts #4 AWG to #1/0 cable size.
#042 533
Accepts #1/0 to #2/0 AWG cable size.
Kit includes one Dinse-style male plug
which attaches to the work and/or weld
cables and plugs into the Dinse-style
recep tacles on the power source.
Extension Kit for Dinse-Style
Cable Connectors
#042 419
Accepts #4 AWG to #1/0 cable size.
#042 534
Accepts #1/0 to #2/0 AWG cable size.
Used to adapt or extend weld and/or work
cables. Kit includes one male Dinse-style plug
and one in-line female Dinse-style receptacle.
Dinse/Tweco
®
Adapter
#042 465
Dinse/Cam-Lok Adapter
#042 466
One-piece adapter with Dinse-style male
plug (to power source) on one end and
female receptacle (Tweco or Cam-Lok for
weld cable connection) on other end.
Coolant Systems
For more information, see the Miller Coolant Systems literature sheet, Index No. AY/7.2.
Coolmate 3
Coolmate 4
Coolmate V3

Ordering Information
Litho in USA
Power Source and Options Stock No. Description Qty. Price
XMT®350 CC/CV #907 161 208 – 575 VAC with Auto-Line
™
#907 161-01-1 208 – 575 VAC with Auto-Line™and Auxiliary Power
#907 161-01-2 230 – 460 VAC with Auto-Line™and Auxiliary Power and CE
#907 161-01-4 208 – 575 VAC with Auto-Line™and Tweco connectors
XMT®350 VS #907 224 208 – 575 VAC with Auto-Line™(without 14-pin, Tweco connectors)
XMT®350 Wire Feeder Packages See page 4
XMT
®
450 CC/CV #907 481 230 – 460 VAC
#907 482 575 VAC
#907 525 400 VAC with Auxiliary Power and CE
Inverter Racks (full or empty) See Lit. Index No. DC/18.81
Gas Valve Kit #195 286 For XMT 350
#300 928 For XMT 450
Accessories
Optima™MIG Pulse Control #043 389 For CC/CV models only. Not for use with XMT 350 VS
Optima™Extension Cords See page 5
WC-24 Weld Control #137 549 For use with Spoolmatic®30A and power sources with 14-pin
HF-251D-1 HF Starter/Stabilizer #042 388 See Lit. Index No. AY/5.1
Wireless Remote Foot Control #300 429 Foot control with wireless 90-ft (27.4 m) operating range
Wireless Remote Hand Control #300 430 Hand control with wireless 300 ft (91.4 m) operating range
RFCS-14 #043 554 Foot control
RHC-14 #242 211 020 Hand control with 20-foot (6 m) cord
#242 211 100 Hand control with 100-foot (30.5 m) cord
RMLS-14 #129 337 Rocker switch
RCC-14 #151 086 Fingertip control
RCCS-14 #043 688 Fingertip control
Extension Cables See page 5
Running Gear
MIGRunner™Cart #195 445
Running Gear Cylinder Rack #300 408 For dual feeders
XMT Cylinder Cart #042 537
Universal Carrying Cart and Cylinder Rack #042 934
Protective Cover #195 478
Wire Feeders/Guns
SuitCase®X-TREME 8VS / X-TREME™12VS #951 181 / #951 184 See Lit. Index No. M/6.4 and M/6.41
SuitCase®8RC / 12RC #951 186 / #951 188 See Lit. Index No. M/6.5
XR
™
-S Control #300 601 Standard model with wire feed speed digital display, jog/purge,
run-in control, and trigger hold. See Lit. Index No. M/1.7
XR™-D Control #300 687 Enhanced model has same features as XR-S model plus advanced digital
and programming capabilities. See Lit. Index No. M/1.7
XR-AlumaFeed
™
#300 509 Advanced model adds Profile Pulse™, synergic control, trigger schedule
select, lock capabilities and flow meter
70 Series #951 196 S-74S. See Lit. Index No. M/3.0
#951 198 S-74D. See Lit. Index No. M/3.0
#951 200 S-74DX. See Lit. Index No. M/3.0
Spoolmatic®30A Spool Gun #130 831 Requires WC-24 for use with 14-pin receptacles
Ironmate™Flux-Cored Guns See Lit. Index No. AY/16.0
Coolant Systems See page 7. See Lit. Index No. AY/7.2
Cable Connectors and Adapters See page 7
Date: Total Quoted Price:
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