Miller Millermatic 350P User manual

TM-1327Q 2012−01
Eff. w/ Serial Number LC447907
Millermatic 350 And
Millermatic 350P
R
R
Processes
Description
Arc Welding Power Source
and Wire Feeder
MIG (GMAW) Welding
Pulsed MIG (GMAW-P)
Flux Cored (FCAW) Welding
File: MIG (GMAW)
Visit our website at
www.MillerWelds.com

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 −INTRODUCTION 3...............................................................
2-1. Serial Number And Rating Label Location 3................................................
2-2. Selecting A Location 3..................................................................
SECTION 3 −SPECIFICATIONS 4..............................................................
3-1. Specifications 4........................................................................
3-2. Duty Cycle And Overheating 4...........................................................
3-3. Volt-Ampere Curve 5...................................................................
3-4. Weld Output Terminals And Selecting Cable Sizes 6.........................................
3-5. Connecting To Weld Output Terminals 7...................................................
SECTION 4 −INSTALLATION 8................................................................
4-1. Installing Work Clamp 8.................................................................
4-2. Installing Welding Gun/Cable Holder 8.....................................................
4-3. Installing Welding Gun 9................................................................
4-4. Connecting Spoolmatic15A Or 30A Gun 10...............................................
4-5. Connecting XR Edge, XR-A Gun, XR-A Python, Or XR - AlumaPro 11...........................
4-6. Setting Gun Polarity For Wire Type 12......................................................
4-7. Installing Gas Supply 13.................................................................
4-8. Installing Wire Spool and Adjusting Hub Tension 14...........................................
4-9. Electrical Service Guide 14...............................................................
4-10. Selecting Input Voltage (200/230/460 Volt Models Only) 15.....................................
4-11. Connecting 3-Phase Input Power 16.......................................................
4-12. Connecting 1-Phase Input Power 17.......................................................
4-13. Threading Welding Wire For MIG Gun 18...................................................
4-14. Threading Welding Wire For XR Edge, XR-A Gun, XR-A Python, Or XR - AlumaPro 19.............
4-15. Threading Welding Wire Through XR Guns 20...............................................
SECTION 5 −OPERATION 21...................................................................
5-1. Controls 21............................................................................
5-2. MIG Mode 22...........................................................................
5-3. Jog Mode 22...........................................................................
5-4. Weld Status 22.........................................................................
5-5. MIG Gun-On-Demand 22.................................................................
5-6. Pulse MIG Mode Voltage Adjustment 22....................................................
5-7. Pulse MIG Gun-On-Demand 22...........................................................
5-8. Tip Saver 22...........................................................................
5-9. Weld Parameters For MIG Mode 24........................................................
5-10. Weld Parameters For Pulse Mode 25.......................................................
SECTION 6 −PROGRAMMING 26...............................................................
6-1. MIG Welding Mode 26...................................................................
6-2. Pulse MIG Welding Mode 27..............................................................
6-3. Timers 28..............................................................................
6-4. Arc Times, Arc Starts, Hot Start, Set Up Push/Pull Motor Torque (SUP) (Aluminum Pulse Only), And Crater Fill . .
29
6-5. Setting Hot Start (Aluminum Pulse Only) Parameters 30.......................................
6-6. Setting Crater Fill 31.....................................................................

TABLE OF CONTENTS
6-7. RecommendedCrater Fill Parameters 32...................................................
6-8. System Reset 34.......................................................................
6-9. Motor Calibration Function Prior To Serial No. LH170741B 35..................................
6-10. Motor Calibration Function Eff w/Serial No. LH170741B 36.....................................
6-11. Set Up Push Motor Torque (SUP) 37.......................................................
SECTION 7 −THEORY OF OPERATION 38.......................................................
SECTION 8 −PRE-POWER TROUBLESHOOTING 42..............................................
8-1. Checking Unit Before Applying Power 42...................................................
8-2. Measuring Input Capacitor Voltage (200/230/460 V Model Shown) 43............................
8-3. Output Diodes D1, D2 44.................................................................
8-4. Input Rectifier SR1, Input Capacitors C3 And C4, And Resistors R11 And R12
(200/230/460 V Model Shown) 45..........................................................
8-5. IGBT Modules PM1, PM2 (200/230/460 V Model Shown) 46...................................
8-6. Diodes D1 And D2 (200/230/460 V Model Shown) 47.........................................
SECTION 9 −TROUBLESHOOTING 48..........................................................
9-1. Troubleshooting Table 48.................................................................
9-2. Help Displays 50........................................................................
9-3. Troubleshooting Circuit Diagram For 200/230/460/575 V Models 52.............................
9-4. Waveforms For Sections 9-3 55...........................................................
9-5. Main Control Board PC1 Testing Information (Prior To LE411272)
(Use With Section 9-6) 56................................................................
9-6. Main Control Board PC1 Test Point Values (Prior To LE411272) 57..............................
9-7. Main Control Board PC1 Testing Information (Eff. w/LE411272)
(Use With Section 9-8) 60................................................................
9-8. Main Control Board PC1 Test Point Values (Eff. w/LE411272) 61................................
9-9. Interconnect Board PC2 Testing Information (200/230/460 V Model Shown)
(Use With Section 9-10) 64...............................................................
9-10. Interconnect Board PC2 Test Point Values 65................................................
9-11. User Interface Board PC3 Testing Information (Use With Section 9-12) 66........................
9-12. User Interface Board PC3 Test Point Values 67..............................................
9-13. Pulse/Tach Board PC6 Testing Information (Use With Section 9-14) 68...........................
9-14. Pulse/Tach Board PC6 Test Point Values 69.................................................
SECTION 10 −MAINTENANCE 70...............................................................
10-1. Routine Maintenance 70.................................................................
10-2. Additional Maintenance (If Necessary) 70...................................................
10-3. Overheating 70.........................................................................
10-4. Ground Clamp And Gun Connections 70....................................................
10-5. Changing Drive Roll and Wire Inlet Guide 71................................................
10-6. Removing Fan Motor 72..................................................................
SECTION 11 −ELECTRICAL DIAGRAMS 73......................................................
SECTION 12 −PARTS LIST (Eff w/LC447907 Thru LE443589) 90....................................
SECTION 13 −PARTS LIST (Eff w/LE443590 Thru LJ420783B) 108...................................
SECTION 14 −PARTS LIST (Eff w/LJ420783B
And Following) 120............................................................................

TM-1327 Page 1Millermatic 350
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-1327AH - 2012−01, safety_stm 2011−10
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. 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.
ELECTRIC SHOCK can kill.
DDo not touch live electrical parts.
DTurn Off welding power source and wire feeder
and disconnect and lockout input power using
line disconnect switch, circuit breakers, or by removing plug from re-
ceptacle, or stop engine before servicing unless the procedure spe-
cifically requires an energized unit.
DInsulate yourself 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
familiar with and following standard safety practices do the job.
DWhen testing 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
capacitors according 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
clothing to prevent burns.
EXPLODING PARTS can injure.
DFailed parts can explode or cause other parts to
explode when 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-
retaining spring 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
support unit.
DIf using lift forks to move unit, be sure forks are long enough to
extend beyond opposite side of unit.
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.

TM-1327 Page 2 Millermatic 350
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-
connecting input power.
ELECTRIC AND MAGNETIC FIELDS (EMF)
can affect Implanted Medical Devices.
DWearers of Pacemakers and other Implanted
Medical Devices 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
starting to 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
electronic equipment 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.
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.
READ INSTRUCTIONS.
DUse Testing Booklet (Part No. 150 853) when
servicing this unit.
DConsult the Owner’s Manual for welding safety
precautions.
DUse only genuine replacement parts from the manufacturer.
DRead and follow all labels and the Technical Manual carefully be-
fore installing, operating, or servicing unit. Read the safety in-
formationat the beginning of the manual and in each section.
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
reproductive harm. Wash hands after use.
1-4. EMF Information
Electric current flowing through any conductor causes localized electric
and magnetic fields (EMF). Welding current creates an EMF field
around the welding circuit and welding equipment. EMF fields may inter-
fere with some medical implants, e.g. pacemakers. Protective
measures for persons wearing medical implants have to be taken. For
example, restrict access for passers−by or conduct individual risk as-
sessment 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:
ImplantedMedical 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-1327 Page 3Millermatic 350
SECTION 2 −INTRODUCTION
2-1. Serial Number And Rating Label Location
The serial number and rating information for this product is located on 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.
1 Line Disconnect Device
Locate unit near correct input power
supply.
!Special installation may be
required where gasoline or
volatile liquids are present −
see NEC Article 511 or CEC
Section 20.
2-2. Selecting A Location
1
18 in
(460 mm)
18 in
(460 mm)
Movement
Location And Airflow
!Do not move or operate
unit where it could tip.
Ref. 803 543-E

TM-1327 Page 4 Millermatic 350
SECTION 3 −SPECIFICATIONS
3-1. Specifications
Rated Output Max. Open
Circuit
Voltage 60 Hz Amps Input at Rated Output
200 V 230 V 460 V 575V KVA KW
300 A at
32 VDC,
60% Duty
Cycle
350 A at
32 VDC,
40% Duty
Cycle
90 Single-Phase 69
(1.7*) 61 (1.5*) 30 (0.75*) 24 (0.5*) 13.1 11.2
Three-Phase 34
(1.7*) 30 (1.5*) 15 (0.75*) 12 (0.5*) 11.6 11.5
* While idling
Wire Type and Diameter Wire Feed Speed Dimensions Net Weight
Solid Steel Stainless Steel Aluminum 50−700 IPM
(1.3−17.8 m/min) H: 34 in. (864 mm) W: 19 in. (483 mm)
D: 41 in. (1041 mm)
181 lb
(82 kg)
.023 −.045 in.
(0.8 −1.1 mm) .030 −.045 in. (0.8 −1.1 mm) .035 −.047 in. (0.9 −1.2 mm)
Operating Temperature Range: −20C to +40C Storage Temperature Range: -30C to + 50C
3-2. Duty Cycle And Overheating
Duty Cycle is percentage of 10
minutes that unit can weld at rated
load without overheating.
If unit overheats, thermistors open,
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
6 Minutes Welding 4 Minutes Resting
0
15
A or V
OR
Reduce Duty Cycle
Minutes
60% Duty Cycle At 300 Amperes 40% Duty Cycle At 350 Amperes
sduty1 5/95 / 217 442-A
10 15 20 25 30 40 50 60 70 80 90 100
100
150
200
225
250
300
400
500
% DUTY CYCLE
WELDING AMPERES
4 Minutes Welding 6 Minutes Resting

TM-1327 Page 5Millermatic 350
3-3. Volt-Ampere Curve
217 443-A
1 Normal Volt-Ampere Curves
The volt-ampere curves show the
normal minimum and maximum
voltage and amperage output
capabilities of the welding power
source. Curves of other settings fall
between the curves shown.
MAX VOLTS
MIN VOLTS
0 50 100 150 200 250 300 350
0
10
20
30
40
50
60
70
80
90
VOLTAGE
AMPERAGE

TM-1327 Page 6 Millermatic 350
3-4. 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
before connecting
to weld output
terminals.
!Do not use worn,
damaged, under-
sized, or poorly
spliced 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)
Ref. 803 912-B
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) 2 ea. 2/0
(2x70) 2 ea. 2/0 (2x70)
300 1 (50) 1/0 (60) 2/0 (70) 3/0 (95) 4/0 (120) 2 ea. 2/0
(2x70) 2 ea. 3/0 (2x95) 2 ea. 3/0 (2x95)
350 1/0 (60) 2/0 (70) 3/0 (95) 4/0 (120) 2 ea. 2/0
(2x70) 2 ea. 3/0 (2x95) 2 ea. 3/0 (2x95) 2 ea. 4/0 (2x120)
400 1/0 (60) 2/0 (70) 3/0 (95) 4/0 (120) 2 ea. 2/0
(2x70) 2 ea. 3/0 (2x95) 2 ea. 4/0 (2x120) 2 ea. 4/0 (2x120)
500 2/0 (70) 3/0 (95) 4/0 (120) 2 ea. 2/0
(2x70) 2 ea. 3/0 (2x95) 2 ea. 4/0 (2x120) 3 ea. 3/0 (3x95) 3 ea. 3/0 (3x95)
* 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-G 2009−08

TM-1327 Page 7Millermatic 350
3-5. Connecting To Weld Output Terminals
803 778-A
!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
output terminal 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
Correct Installation Incorrect Installation
1
weld cable terminal
and copper bar.

TM-1327 Page 8 Millermatic 350
SECTION 4 −INSTALLATION
4-1. Installing Work Clamp
.Do not extend or downsize the
work cable. Only use the work
cable supplied with the unit.
1 Work Cable
2 Boot
Route cable through front panel
opening. Slide boot onto work
cable.
3 Negative (−) Output Terminal
Connect cable to terminal and
cover connection with boot.
Close door.
803 540-D
Tools Needed:
3/4 in.
3
2
1
4-2. Installing Welding Gun/Cable Holder
1 Welding Gun/Cable Holder
2 Wrapper
3 Screw Locations
Remove screws from side panel.
Place holder against side panel and
align screw holes. Secure holder to
side panel with the previously
removed screws.
Ref. 803 545-D / Ref. 803 539-C
1
2
3

TM-1327 Page 9Millermatic 350
4-3. Installing Welding Gun
1 Drive Assembly
2 Gun Securing Knob
3 Gun End
Loosen securing knob. Insert gun
end through opening until it bottoms
against drive assembly (make sure
gun end does not touch drive rolls).
Tighten knob.
4 Gun Trigger Plug
Insert plug into receptacle, and
tighten threaded collar.
Close door.
Ref. 803 544-C / Ref. 803 541-C
1
4
3
2

TM-1327 Page 10 Millermatic 350
4-4. Connecting Spoolmatic)15A Or 30A Gun
803 568-D / Ref. 803 540-D / Ref. 803 544-C
1 Gun Trigger Plug
Insert plug into receptacle, and
tighten threaded collar.
2 Weld Cable
3 Shielding Gas Hose
Route weld cable and gas hose
through opening in front panel.
4 Positive Weld Output Terminal
Connect weld cable to weld output
terminal.
5 Regulator/Flowmeter
Route shielding gas hose through
wire drive compartment, out
opening in rear panel, and up to
regulator/flowmeter. Connect gas
hose to regulator/flowmeter.
Tools Needed:
3/4, 5/8 in.
1
23
Î
4
2
5
3

TM-1327 Page 11Millermatic 350
4-5. Connecting XR Edge, XR-A Gun, XR-A Python, Or XR - AlumaPro
803 569-C / Ref. 803 570 -C / Ref. 803 540-D / Ref. 803 463
.XR Edge guns prior to serial no.
LE079101 require an adapter
cord (part no. 195 498).
1 Gun End
2 Gun Liner
3 Wire Outlet Guide
Trim excess liner from end of gun
so no more than 3/32 in. (2.4 mm) of
liner extends past wire outlet guide.
4 Gun Securing Knob
Loosen securing knob. Insert gun
end through opening until it bottoms
against drive assembly (make sure
gun end does not touch drive rolls).
Tighten knob.
Be sure to change drive rolls to the
proper size and type.
5 Gun Trigger Plug
Insert plug into receptacle, and
tighten threaded collar.
32
3/32 in.
(2.4 mm)
.Be sure to trim liner to proper extension.
1
5
4

TM-1327 Page 12 Millermatic 350
4-6. Setting Gun Polarity For Wire Type
1 Polarity Changeover Information
Always read and follow manufacture’s
recommendedpolarity.
1
3/4, 11/16 in.
Ref. 803 541-A
Changing Polarity
D
Wire Drive
Assembly Lead Work Clamp Lead
+Positive
Terminal
Shown as shipped −Electrode Positive (DCEP): For
solid steel, stainless steel, aluminum, or flux core with
gas wires (GMAW).
-Negative
Terminal
Electrode Negative (DCEN): Reverse lead connections
at terminals from that shown above for gasless flux core
wires (FCAW). Drive assembly becomes negative.
D

TM-1327 Page 13Millermatic 350
4-7. Installing Gas Supply
803 542-C
Tools Needed:
1-1/8, 5/8 in.
1
2
3
4
5
7
Rear Panel
6
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 20 cfh (cubic
feet per hour). 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.
1
2
3
8 9
Argon Gas Or Mixed Gas
CO2Gas

TM-1327 Page 14 Millermatic 350
4-8. Installing Wire Spool and Adjusting Hub Tension
Ref. 805 023-A
When a slight force is needed to turn spool, tension is set.
15/16 in.
Use compression spring with
8 in. (200 mm) spools.
Tools Needed:
4-9. Electrical Service Guide
Failure to follow these electrical service guide recommendations could create an electric shock or fire hazard. These recommenda-
tions are for a dedicated branch circuit sized for the rated output and duty cycle of the welding power source.
60 Hz Single Phase 60 Hz Three Phase
Input Voltage (V) 200 230 460 575 200 230 460 575
Input Amperes (A) At Rated Output 69 61 30 24 34 30 15 12
Max Recommended Standard Fuse Rating In Amperes1
Time-Delay Fuses 280 70 35 25 40 35 15 10
Normal Operating Fuses 3100 90 40 35 50 45 20 15
Min Input Conductor Size In AWG 46 8 10 12 10 10 14 14
Max Recommended Input Conductor Length In Feet (Meters) 101
(31) 86 (26) 229 (70) 217 (66) 86 (26) 114 (35) 178 (54) 227 (85)
Min Grounding Conductor Size In AWG 48 8 10 12 10 10 14 14
Reference: 2011 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.
NOTICE −This unit is either a 200/230/460 ac input voltage model or 460/575 ac input voltage model. See rating label on unit and check voltage
available at site to be sure it matches the voltage specified on the rating label.

TM-1327 Page 15Millermatic 350
4-10. Selecting Input Voltage (200/230/460 Volt Models Only)
803 539-C / 804 042-A
!Turn Off welding power
source, disconnect input
power, and check voltage on
input capacitors according
to Section 8-2 before
proceeding.
.Check input voltage available
at site.
.Incorrect linking can damage
unit and void the warranty.
1 Voltage Selection View
Window
Check voltage selected in unit.
Changing selection is only neces-
sary if selected value does not
match available input voltage.
2 Relinking Board PC6
3 Mounting Screws
4 Receptacle RC23
(Connection For 230 VAC Or
208 VAC Input Power)
5 Receptacle RC46
(Connection For 460 VAC
Input Power)
Move relinking board as needed
and connect plug PLG32 (in unit) to
RC23 or RC46 according to input
power voltage.
Tools Needed:
5/16 in.
.Be sure to reinstall all four screws
securing relinking board in place.
2
3
4
3
5
1

TM-1327 Page 16 Millermatic 350
4-11. Connecting 3-Phase Input Power
Ref. 803 543-E / 803 766-A
!Installationmust meet all National and
Local Codes - have only qualified
persons make this installation.
!Disconnect and lockout/tagout input
power before connecting input
conductors from unit.
!Always connect green or green/yellow
conductor to supply grounding terminal
first, and never to a line terminal.
!Warning: This unit is either a
200/230/460AC input voltage model or
460/575 AC input voltage model. See
rating label on unit and check voltage
available at site to be sure it matches
the voltage specified on the rating
label.
1 Input Power Cord Strain Relief
2 Input Power Cord
3 Disconnect Device (switch shown in
the OFF position)
4 Green Or Green/Yellow Grounding
Conductor
5 Disconnect Device Grounding Terminal
6 Input Conductors (L1, L2 And L3)
7 Disconnect Device Line Terminals
Connect green or green/yellow grounding
conductor to disconnect device grounding
terminal first.
Connect input conductors L1, L2, and L3 to
disconnect device line terminals.
8 Over-Current Protection
Select type and size of over-current
protection using Section 4-9 (fused
disconnect switch shown).
Close and secure door on disconnect device.
Remove lockout/tagout device, and place
switch in the On position.
Tools Needed:
2
1
Rear Panel
= GND/PE Earth Ground
3
3
4
5
7
6
8
L1
L2
L3