Miller AUTO ARC 255 Owner's manual

AUTO ARC 255
Miller
Brand
Miller
Model
AUTO ARC 255
Category
Welding System
Type
Owner's manual

This manual is also suitable for

The Miller AUTO ARC 255 is a versatile welding power source with a variety of features that make it ideal for both home and professional use. It offers precise control over the welding process, allowing users to achieve high-quality welds on a variety of metals. With its user-friendly interface and durable construction, the AUTO ARC 255 is an excellent choice for anyone looking for a reliable and powerful welding machine.

The Miller AUTO ARC 255 is a versatile welding power source with a variety of features that make it ideal for both home and professional use. It offers precise control over the welding process, allowing users to achieve high-quality welds on a variety of metals. With its user-friendly interface and durable construction, the AUTO ARC 255 is an excellent choice for anyone looking for a reliable and powerful welding machine.

AUTO
ARCJ5~
August
1992
Effective
With
Form:
Serial
No.
OM-157
066
KC286703
OWNERS
MANUAL
U
u
u
Read
and
follow
these
instructions
and
all
safety
blocks
carefully.
Have
only
trained
and
qualified
persons
install,
operate,
or
service
this
unit.
Call
your
distributor
if
you
do
not
understand
the
directions.
U
Give
this
manual
to
the
operator.
U
For
help,
call
your
distributor,
or:
MILLER
ELECTRIC
Mfg.
Co.,
P.O.
Box
1079,
Appleton,
WI
54912
414-734-9821
Auto
Arcfi
255
CV/DC
Welding
Power
Source/Wire
Feeder
U
For
GMAW
And
FCAW
Welding
Uses
.023
.045
Hard
Wire
And
.030
.045
Flux-Cored
Wire
U
200
Amperes,
28
Volts
DC
At
60%
Duty
Cycle
Uses
Single-Phase
Input
Power
U
Overheating
And
Motor
Overload
Protection
Includes
Gun
And
Shielding
Gas
Valve
auto_arc
8192
ST.1
57
072
PRINTED
IN
USA
The
following
safety
alert
symbol
and
signal
words
are
used
throughout
this
manual
to
call
attention
to
and
identify
different
levels
of
hazard
and
special
instructions.
a
WARNING
WARNING
statements
identify
procedures
or
practices
which
must
be
followed
to
avoid
serious
personal
injury
or
loss
of
life.
a
CAUTION
CAUTION
statements
identify
procedures
or
practices
which
must
be
followed
to
avoid
minor
personal
injury
or
damage
to
this
equipment.
~
IMPORTANT:
statements
identify
special
instructions
necessary
for
the
most
efficient
operation
of
this
equipment.
ARC
WELDING
SAFETY
PRECAUTIONS
ELECTRIC
SHOCK
can
kill.
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.
1.
Do
not
touch
live
electrical
parts.
2.
Wear
dry,
hole-free
insulating
gloves
and
body
protection.
3.
Insulate
yourself
from
work
and
ground
using
dry
insulating
mats
or
covers.
4.
Disconnect
input
power
or
stop
engine
before
installing
or
servicing
this
equipment.
5.
Properly
install
and
ground
this
equipment
according
to
its
Owners
Manual
and
national,
state,
and
local
codes.
Turn
off
all
equipment
when
not
in
use.
Do
not
use
worn,
damaged,
undersized,
or
poorly
spliced
cables.
Do
not
wrap
cables
around
your
body.
Ground
the
workpiece
to
a
good
electrical
(earth)
ground.
Do
not
touch
electrode
while
in
contact
with
the
work
(ground)
circuit.
11.
Use
only
well-maintained
equipment.
Repair
or
replace
damaged
parts
at
once.
12.
Wear
a
safety
harness
to
prevent
falling
if
working
above
floor
level.
13.
Keep
all
panels
and
covers
securely
in
place.
a
WARNING
ARC
WELDING
can
be
hazardous.
PROTECT
YOURSELF
AND
OTHERS
FROM
POSSIBLE
SERIOUS
INJURY
OR
DEATH.
KEEP
CHILDREN
AWAY.
PACEMAKER
WEARERS
KEEP
AWAY
UNTIL
CONSULTING
YOUR
DOCTOR.
In
welding,
as
in
most
jobs,
exposure
to
certain
hazards
occurs.
Welding
is
safe
when
precautions
are
taken.
The
safety
information
given
below
is
only
a
summary
of
the
more
complete
safety
information
that
will
be
found
in
the
Safety
Standards
listed
on
the
next
page.
Read
and
follow
all
Safety
Standards.
HAVE
ALL
INSTALLATION,
OPERATION,
MAINTENANCE,
AND
REPAIR
WORK
PERFORMED
ONLY
BY
QUALIFIED
PEOPLE.
6.
7.
8.
9.
10.
~,
/~
~
ARC
RAYS
can
burn
eyes
and
skIn;
NOISE
can
damage
hearing.
Arc
rays
from
the
welding
process
produce
intense
heat
and
strong
ultraviolet
rays
that
can
burn
eyes
~
Noise
from
some
processes
can
damage
g.
1.
2.
3.
4.
5.
Wear
a
welding
helmet
fitted
with
a
proper
shade
of
filter
(see
ANSI
Z49.
I
listed
in
Safety
Standards)
to
protect
your
face
and
eyes
when
welding
or
watching.
Wear
approved
safety
glasses.
Side
shields
recommended.
Use
protective
screens
or
barriers
to
protect
others
from
flash
and
glare;
warn
others
not
to
watch
the
arc.
Wear
protective
clothing
made
from
durable,
flame-resistant
material
(wool
and
leather)
and
foot
protection.
Use
approved
ear
plugs
or
ear
muffs
if
noise
level
is
high.
FUMES
AND
GASES
can
be
hazardous
to
your
health.
Welding
producesfumesand
gases.
Breathing
these
fumes
and
gases
can
be
hazardous
to
your
health.
5.
Work
in
a
confined
space
only
if
it
is
well
ventilated,
or
while
wearing
an
air-supplied
respirator.
Shielding
gases
used
for
welding
can
displace
air
causing
injury
or
death.
Be
sure
the
breathing
air
is
safe.
1.
Keep
your
head
out
of
the
fumes.
Do
not
breathe
the
fumes,
.
2.
If
inside,
ventilate
the
area
and/or
use
exhaust
at
the
arc
to
remove
welding
fumes
and
gases.
3.
If
ventilation
is
poor,
use
an
approved
air-supplied
respirator.
4.
Read
the
Material
Safety
Data
Sheets
(MSDSs)
and
the
manufacturers
instruction
for
metals,
consumables,
coatings,
.
and
cleaners,
6.
7.
Do
not
weld
in
locations
near
degreasing,
cleaning,
or
spraying
operations.
The
heat
and
rays
of
the
arc
can
react
with
vapors
to
form
highly
toxic
and
imtating
gases.
Do
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
if
necessary,
while
wearing
an
air-supplied
respirator.
The
coatings
and
any
metals
containing
these
elements
can
give
off
toxic
fumes
if
welded.
WELDING
can
cause
fire
or
explosion.
Sparks
and
spatter
fly
off
from
the
welding
arc.
The
flying
sparks
and
hot
metal,
weld
spatter,
hot
workpiece,
and
hot
equipment
can
cause
fires
and
burns.
Accidental
contact
of
electrode
or
welding
wire
to
metal
objects
can
cause
sparks,
overheating,
or
fire.
1.
Protect
yourself
and
others
from
flying
sparks
and
hot
metal.
2.
Do
not
weld
where
flying
sparks
can
strike
flammable
material.
3.
Remove
all
flammables
within
35
ft
(10.7
m)
of
the
welding
arc.
If
this
is
not
possible,
tightly
cover
them
with
approved
covers.
4.
Be
alert
that
welding
sparks
and
hot
materials
from
welding
can
small
cracks
and
openings
to
adjacent
areas.
CYLINDERS
can
explode
if
damaged.
Shielding
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.
Protect
compressed
gas
cylinders
from
excessive
heat,
mechanical
shocks,
and
arcs.
2.
Install
and
secure
cylinders
in
an
upright
position
by
chaining
them
to
a
stationary
support
or
equipment
cylinder
rack
to
prevent
falling
or
tipping.
Watch
for
fire,
and
keep
a
fire
extinguisher
nearby.
Be
aware
that
welding
on a
ceiling,
floor,
bulkhead,
or
partition
can
cause
fire
on
the
hidden
side.
Do
not
weld
on
closed
containers
such
as
tanks
or
drums.
Connect
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
and
fire
hazards.
9.
Do
not
use
welder
to
thaw
frozen
pipes.
10.
Remove
stick
electrode
from
holder
or
cut
off
welding
wire
at
contact
tip
when
not
in
use.
11.
Wearoil-free
protective
garments
such
as
leather
gloves,
heavy
shirt,
cuffless
trousers,
high
shoes,
and
a
cap.
3.
Keep
cylinders
away
from
any
welding
or
other
electrical
circuits.
4.
Never
allow
a
welding
electrode
to
touch
any
cylinder.
5.
Use
only
correct
shielding
gas
cylinders,
regulators,
hoses,
and
fittings
designed
for
the
specific
application;
maintain
them
and
associated
parts
in
good
condition.
6.
Turn
face
away
from
valve
outlet
when
opening
cylinder
valve.
7.
Keep
protective
cap
in
place
over
valve
except
when
cylinder
is
in
use
or
connected
for
use.
8.
Read
and
follow
instructions
on
compressed
gas
cylinders.
associated
equipment,
and
CGA
publication
P.1
listed
in
Safety
Standards.
PRINCIPAL
SAFETY
STANDARDS
Safety
in
Welding
and
Cutting,
ANSI
Standard
Z49.1,
from
American
Welding
Society,
550
N.W.
LeJeune
Ad,
Miami
FL
33126
Safetyand
Health
Standards,
OSHA
29
CFR
1910,
from
Superintendent
of
Documents,
U.S.
Government
Printing
Office,
Washington,
D.C.
20402.
Recommended
Safe
Practices
for
the
Preparation
for
Welding
and
Cutting
of
Containers
That
Have
Held
Hazardous
Substances,
American
Welding
Society
Standard
AWS
F4.
1,
from
American
Welding
Society,
550
N.W.
LeJeune
Rd.
Miami,
FL
33126
National
Electrical
Code,
NFPA
Standard
70,
from
National
Fire
Protection
Association,
Batterymarch
Park,
Quincy,
MA
02269.
Safe
Handling
of
Compressed
Gases
in
Cylinders,
CGA
Pamphlet
P-I,
from
Compressed
Gas
Association,
1235
Jefferson
Davis
Highway,
Suite
501,
Arlington,
VA
22202.
Code
for
Safety
in
Welding
and
Cutting,
CSA
Standard
Wi
17.2,
from
Canadian
Standards
Association,
Standards
Sales,
178
Rexdale
Boulevard,
Rexdale,
Ontario,
Canada
M9W
1
R3.
Safe
Practices
For
Occupation
And
Educational
Eye
And
Face
Protection,
ANSI
Standard
Z87.
1,
from
American
National
Standards
Institute,
1430
Broadway,
New
York,
NY
10018.
Cutting
And
Welding
Processes,
NFPA
Standard
519,
from
National
Fire
Protection
Association,
Batterymarch
Park,
Quincy,
MA
02269.
TABLE
OF
CONTENTS
SECTION
1
SPECIFICATIONS
1
7
SECTION
6
PARTS
LIST
8
8
9
10
ii
13
14
5.
6.
7.
8.
FLYING
SPARKS
AND
HOT
METAL
can
1.
Wear
approved
face
shield
or
safety
goggles.
Side
shields
cause
injury,
recommended.
Chipping
and
grinding
cause
flying
metal.
As
welds
2.
Wear
proper
body
protection
to
protect
skin.
cool,
they
can
throw
off
slag.
1.1.
Volt-Ampere
Curve
And
Duty
Cycle
Chart
SECTION
2
INSTALLATION
2-1.
Installing
Work
Clamp
2
2-2.
Installing
Gas
Supply
2
2-3.
Gun
Polarity
And
Range
Selector
3
2-4.
Installing
Drive
Rolls
And
Welding
Gun
3
2-5.
Connecting
Input
Power
4
2-6.
Threading
And
Feeding
Welding
Wire
6
SECTION
3OPERATION
SECTION
4
MAINTENANCE
&
TROUBLESHOOTING
4-i.
Thermal
Overload
Protection
4-2.
Overload
Protection
4-3.
Wire
Drive
Assembly
Maintenance
4-4.
Gun
Maintenance
4-5.
Troubleshooting
SECTION
5
ELECTRICAL
DIAGRAMS
11
Figure
6-1.
Main
Assembly
Figure
6-2.
MWG-21C
Gun
Figure
6-3.
Baffle
w/Cmpts
15
SECTION
1
SPECIFICATIONS
Table
1-1.
Welding
Power
Source
Type
Of
Output
Rated
Weld
Output
Type
Of
Input
Power
In
put
Amperes
At
Rated
Output
KVA/KW
Used
At
Rated
Output
Max.
Open-Circuit
Voltage
Control
Circuit
Voltage
At
Gun
Welding
Processes
Calculated
Speed
Range
At
No
Load
Wire
Diameter
Range
Overall
Dimensions
Weight
(j~
~
>
c.~
0
Direct
CurrentJConstant
Voltage
(DC/CV)
200
Amperes.
28
Volts
DC,
60%
Duty
Cycle
Single-Phase;
60
Hz;
At
200, 230, 460,
or
575
Volts
AC
46A
At
200V,
40A
At
230V,
20A
At
460V,
I
6A
At
575V
9.5
kVAI8.3
kW
42
Volts
DC
24
Volts
DC
Specifications
Description
Welding
Gun
Gas
Metal
Arc
(GMAW)
And
Flux
Cored
Arc
Welding
(FCAW)
128
To
1051
ipm
(3.2
To
266.9
mpm)
.030
To
.045
in.
(0.8
To
1.1
mm)
Flux
Cored
Wire,
.023
To
.045
in.
(0.6
To
1.1
mm)
Hard
Wire
Length:
37
in.
(940mm);
Width:
19
in.
(483mm);
Height:
30-1/4
in.
(768
mm)
Net:
225
lbs.
(102
kg);
Ship:
271
lbs.
(123
kg)
Rated
Output
(Air
Cooled)
200
Amperes
At
10
0%
Duty
Cycle
Using
CO2
Shielding
Gas
Cable
Length
12-1/2
ft.
(3.8
m)
1-1.
Volt-Ampere
Curve
And
Duty
CycI
e
Chart
a
CAUTION
U
SING
GUN
BEYOND
DUTY
CYCLE
RATING
can
damage
gun.
Do
not
use
gun
beyond
rated
amperage
when
using
CO2
shiel
ding
gas.
Use
gun
at
30%
duty
cycle
when
using
mixed
shielding
gas.
wfw~m8
I
10/91
The
volt-ampere
curves
show
the
minimum
and
maximum
voltage
and
amperage
output
capabilities
of
the
welding
power
source.
Curves
of
other
settings
fall
be
tween
the
curves
shown.
Duty
cycle
is
how
long
the
unit
can
operate
within
a
ten
minute
period
without
causing
overheating
or
damage.
This
unit
is
rated
at
60%
duty
cycle
allowing
welding
6
minutes
out
of
every
10
minutes.
This
gun
is
rated
at
100%
duty
cycle
when
using
CO2
shielding
D.C.
A~PES
,
~:
RAr~CUTFtrrt
gas
and
30%
when
using
mixed
3OO~
.4
shielding
gas.
=
=
=
=
=
=
=
~
:
-
-
-t
20
30
40
60
60 SO
SO~0
Z
DUTY
CYCLE
ssbl.1
10/91
S9-049424-CIsbl.3
10/91
SB.150215
Figure
1-1.
Volt-Ampere
Curve
And
Duty
Cycle
Chart
OM-157
066
Page
1
Tools
Needed:
~II~
1/2
in..
3/4
in.
SECTION
2
INSTALLATION
4
1
Work
Cable
2
Boot
Slide
boot
onto
work
cable.
Route
cable
out
front
panel
opening
from
inside.
3
Negative
()
Output
Terminal
Connect
cable
to
terminal
and
cov
er
connection
with
boot.
4
Hardware
5
Work
Clamp
Route
cable
through
clamp
handle
and
secure
to
top
of
clamp
with
hardware.
Close
door.
Ref.
ST-154
630
2-2.
Installing
Gas
Supply
a
WARNING
CYLINDERS
can
explode
if
damaged.
Keep
cylinders
away
from
welding
and
other
electrical
circuits.
Never
touch
cylinder
with
welding
electrode.
Always
secure
cylinder
to
running
gear,
wall,
or
other
stationary
support.
BUILDUP
OF
SHIELDING
GAS
can
harm
health
or
kill.
Shut
off
shielding
gas
supply
when
not
in
use.
2-1.
Installing
Work
Clamp
5
2
Figure
2-1.
Installing
Work
Clamp
warn4.1
9/91
1
Cylinder
Bracket
2
S-Hook
Crimp
between
small
hole
in
brack
et
and
chain.
3
Chain
4
Snap
Crimp
onto
open
end
of
chain.
Obtain
gas
cylinder
and
chain
to
running
gear.
5
Cap
6
Cylinder
Valve
Remove
cap,
stand
to
side
of
valve,
and
open
valve
slightly.
Gas
flow
blows
dust
and
dirt
from
valve.
Close
valve.
7
Cylinder
8
CO2
Washer
9
Regulator
Install
onto
gas
cylinder
so
that
face
is
vertical.
10
Flowmeter
11
Gas
Hose
Connection
Fitting
has
5/8-18
right-hand
threads.
Obtain
gas
hose
with
fit
tings,
and
install
between
cylinder
and
welding
power
source.
12
Flow
Adjust
Typical
flow
rate
is
20
cfh
(Cubic
feet
per
hour).
ssb3.1
2/~2
ST.154
583
/
Ref.
ST-log
492
Tools
Needed:
11/8
in.,
FIgure
2-2.
Typical
CO2
Regulator/Flowmeter
Installation
2-3.
Gun
Polarity
And
Range
Selector
__
a
WARNING
ELECTRIC
SHOCK
can
kill.
Do
not
touch
live
electrical
parts.
Turn
OFF
welding
power
source,
and
disconnect
input
power
before
inspecting
or
installing.
swa,nI.1
9/91
HIGH
RANG
o~o
ol
LOW
RANG
~o
o~o
1
Polarity
Changeover
Label
2
Wire
Drive
Assembly
3
Positive
(+)
Output
Terminal
4
Negative
()
Output
Terminal
Always
read
and
follow
wire
man
ufacturers
recommended
polarity.
5
Range
Selector
Arc
voltage
is
fine
tuned
using
VOLTAGE
switch
(see
Figure
3-2).
See
rear
cover
for
settings.
6
Range
Label
Move
bar
for
desired
range.
7
Circuit
Breaker
CB1
(see
Section
4-2).
8
Pilot
Light
(see
Section
4.1)
Close
door.
Ref.
ST-153
874-A
Tools
Needed:
~
3/4
in.,
11/16
in.
Figure
2-3.
Gun
Polarity
Connections
And
Range
Selector
Location
2-4.
InstallIng
Drive
Rolls
And
Welding
Gun
I
Pressure
Adjustment
2
Pressure
Assembly
3
Drive
Roll
4
Securing
Screw
Install
correct
drive
roll
for
wire
size
and
type
using
supplied
screws.
5
Wire
Drive
Assembly
6
Gun
Securing
Knob
7
Gun
End
Loosen
securing
knob.
Insert
gun
end
through
opening
until
it
bot
toms
against
drive
assembly.
Tighten
knob.
8
Gun
Trigger
Plug
Insert
into
receptacle,
and
tighten
threaded
collar.
Close
pressure
assembly.
Close
door.
ST-
154
621
/
Ref.
ST-154
624
.7
6
Figure
2-4.
Gun
Connections
OM~157O66Page3
B.
Connecting
Input
Power
Table
2-1.
Electrical
Service
Requirements*
input
Voltage
200
230
460
575
Input
Amperes
At
Rated
Output
48
41
21
17
These
vaiuee
are
calculated
from
the
1990
editIon
of
the
National
Electrical
Code
(NEC).
Circuit
Breaker
Size
Range
In
Amperes
71
thru
95
62
thru
83
31
thni
41
25
thru
33
Circuit
breaker
range
is
150%
to
not
more
than
200%
of
rated
Input
amper
age
of
the
welding
power
source
(Article
630-12(a)
of
NEC).
Fuse
Size
In
Amperes2
70
60
30
25
2
Standard
fue,
size
is
that
cioaeat
to
150%
of
rated
input
amperage
of
the
welding
power
source
(Article
630-126
of
NEC).
Input
Conduct3or
Size
in
AWG/Kcmii
8
8
12
14
input
conductor
size
is
for
insulated
copper
wire
with
75C
rating
with
not
more
thin
three
single
current-carrying
conductors
in
a
cable
or
raceway
(Article
630-16
of
NEC).
Maximum
input
Conductor
Length
In
Feet
(Meters)4
89
(27)
117
(36)
188
.
(57)
190
(58)
Maximumtengthistopventmorethana3%voltagedropbetweenservlce
entrance
and
input
termInals
of
the
welding
power
source
(Articles
210-t9(a)
and
215-2(b)
of
NEC).
Grounding
Conductor
Size
In
AWGIKcmiI5
8
10
12
14
The
groundIng
conductor
shsll
be
colored
Or
identified
as
specified
in
the
NEC.
Grounding
conductor
size
for
copper
wire
is
not
required
to
be
larger
than
input
conductor
(ArtIcle
250-95
of
NEC).
S-0092-C
Rave
only
qualified
persons
make
this
installation.
1
Single-Phase
Line
Discon
nect
Switch
Of
Proper
Rating
2
Grounding
Conductor
Green
Or
Green
With
Yellow
Stripe(s)
3
Input
Conductors
4
230
Volts
AC
Wall
Recep
tacle
For
wall
receptacle
connection,
se
lect
size
and
length
of
input
con
ductors
and
grounding
conductor
using
Table
2-1.
Conductor
insula
tion
must
comply
with
national.
state,
and
local
electrical
codes.
Install
and
connect
input
conduc
tors
and
grounding
conductor
in
conduit
or
equivalent
between
wall
receptacle
and
deenergized
(me
disconnect
switch.
Be
sure
grounding
conductor
goes
to
an
earth
ground.
5
Line
Fuses
Or
Circuit
Break
ers
Select
fuses
or
circuit
breakers
us
ing
Table
2-1.
Install
into
deener
gized
line
disconnect
switch.
6
Input
Power
Plug
Turn
off
unit
POWER
switch,
and
connect
plug
to
wall
receptacle.
Ref.
ST-154
619-A/
Ref.
ST-149
405-a
5
3
Figure
2-6.
Connecting
Input
Power
2-6.
Threading
And
Feeding
Welding
Wire
a
WARNING
CYLINDERS
can
explode
if
damaged.
Keep
cylinders
away
from
welding
and
other
electrical
circuits.
Never
touch
cylinder
with
welding
electrode.
Always
secure
cylinder
to
running
gear,
wall,
or
other
stationary
support.
ELECTRIC
SHOCK
can
kill.
Do
not
touch
live
electrical
parts.
The
welding
wire,
drive
rolls,
drive
assembly,
and
all
metal
parts
touching
the
welding
wire
are
electrically
live
when
welding
or
feeding
wire
using
gun
trigger.
WELDING
WIRE
can
cause
puncture
wounds.
Do
not
press
gun
trigger
until
instructed
to
do
so.
Do
not
point
gun
toward
any
part
of
the
body,
other
people,
or
any
metal
when
threading
welding
wire.
HOT
SURFACES
can
burn
skin.
Allow
gun
to
cool
before
touching.
swRrn5.1
10191
I
swarn2.I
9/91
Figure
2-7.
Feeding
Welding
Wire
1
2
.3
5
6
9
1
Wire
Spool
2
Hub
Tension
Nut
Grasp
spool
in
one
hand
and
turn
while
using
a
wrench
to
adjust
nut.
When
a
slight
force
is
needed
to
turn
spool,
tension
is
set.
Loosen
wire
from
spool
and
cut
off
bentwire
and
pull6in.
(150
mm)
of
wire
from
spool.
3
Pressure
Adjustment
Open
pressure
assembly
4
Wire
Inlet
Guide
5
Drive
Roll
6
Wire
Outlet
Guide
Thread
wire
through
inlet
guide,
along
drive
roll
groove,
and
into
outlet
guide.
Close
pressure
as
sembly.
Lay
gun
cable
Out
straight.
7
Nozzle
8
Contact
Tube
Remove
nozzle
and
contact
tube.
9
Gun
Trigger
Tum
ON
unit,
press
gun
trigger,
and
feed
2
in.
(55
mm)
of
wire
out
of
gun.
Turn
OFF
unit
and
reinstall
contact
tube
and
nozzle.
10
Adjusting
Pressure
Turn
ON
unit
and
check
drive
roll
pressure
by
feeding
wire
against
a
wood
board
or
concrete
surface:
wire
should
feed
steadily
without
slipping.
Tighten
pressure
adjustment
if
nec
essary.
Close
door.
Tools
Needed:
Ret.
ST.
154626/
S.0627-A
8
OM-157
066
Page
6
SECTION
3OPERATION
I
Wire
Speed
Control
Use
control
to
set
wire
feed
speed.
2
Wire
Speed
Low
Range/Full
Range
Switch
For
better control
of
wire
speed
use
LOW
RANGE
when
wire
speed
is
between
minimum
and
350
pm.
3
Voltage
Switch
Use
switch
and
Range
Selector
(see
Section
2-3)
to
set
arc
voltage.
Step
6
of
LOW
range
and
Step
I
of
HIGH
range
overlap.
4
Pilot
Light
5
Power
Switch
Use
switch
to
turn
unit
ON
and
OFF.
The
pilot
light
comes
on
when
unit
is
turned
on.
6
Work
Clamp
Use
wire
brush
or
sandpaper
to
clean
metal
at
weld
joint
area.
Connect
work
clamp
to
clean,
paint-free
location
on
workpiece,
as
close
as
possible
to
weld
area.
READ
SAFETY
BLOCKS
at
beginning
MOVING
PARTS
can
cause
injury.
ARCING
can
damage
switch.
Keep
away
from
pinch
points
such
as
drive
rolls.
Keep
all
doors,
panels,
covers,
and
guards
closed
Do
not
change
VOLTAGE
switch
position
while
welding.
and
securely
in
place.
Arcing
inside
switch
can
damage
contacts,
causing
switch
to
fail.
1
2
~
3
/
~
1
Insulating
Gloves
2
Safety
Glasses
With
Side
Shields
3
Welding
Helmet
glasses
with
side
shields,
and
a
Wear
dry
insulating
gloves,
safety
welding
helmet
with
a
correct
shade
of
filter
(see
ANSI
Z49.1).
sD3.1
10/91
Figure
3-1.
Safety
Equipment
1
2
3
FIgure
3-2.
Controls
Tools
Needed:
Ret.
ST-I
54
822.A
/
Ret
ST.152
123
/
Ret.
ST-155
398
~7
~
~L
7
SECTION
4
MAINTENANCE
&
TROUBLESHOOTING
a
WARNING
ELECTRIC
SHOCK
can
kill.
Do
not
touch
live
electrical
parts.
Turn
OFF
welding
power
source,
and
disconnect
input
power
before
inspecting,
maintaining,
or
servicing.
HOT
PARTS
can
cause
severe
burns.
Allow
cooling
period
before
maintaining
or
servicing.
~
r
M
Keep
away
from
moving
parts.
OVING
PARTS
can
cause
injury.
Keep
away
from
pinch
points
such
as
drive
rolls.
9~
Maintenance
and
troubleshooting
to
be
performed
only
by
qualified
persons,
5warnB
2
¶0191
Table
4-1.
Maintenance
Schedule
Time
Maintenance
Before
each
use.
Tighten
all
connections.
Check
gun
and
clean
nozzle.
After
each
spool
of
wire.
Blow
out
gun
liner.
Clean
and
check
wire
drive
parts;
replace
as
necessary.
Every
3
months.
Tape
or
replace
cracked
cables:
clean
and
tighten
connections.
Replace
unreadable
labels.
Every
6
months.
Blow
out
or
vacuum
inside
of
unit.
4-1.
Thermal
Overload
Protection
If
the
unit
overheats,
thermostat
TP1
opens
stopping
all
weld
output.
If
this
condition
occurs,
the
light
next
to
the
circuit
breaker
goes
out.
Allow
a
cooling
period
of
about
15
minutes
before
continuing
operation.
4-2.
Overload
Protection
I
READ
Sectlo
SAFETY
BLOCKS
at
start
of
n
4
before
proceeding.
A.
Circuit
Breaker
CBI
Circuit
breaker
CB1
,
under
side
door,
protects
the
wire
drive
motor
from
overload.
If
CB1
opens,
pilot
PL2
goes
out,
and
wire
feed
stops.
Check
gun
liner
for
blockage
or
kinks,
and
check
for
jammed
wire,
binding
drive
gear,
or
misaligned
drive
rolls.
Allow
a
cooling
period
before
resetting
CB1.
B.
Fuses
Fl
And
F2
Turn
OFF
unit
and
disconnect
input
power.
1
Fuse
Fl
(See
Parts
List
For
Rating)
Fl
protects
the
115
volts
ac
wind
ing
of
transformer
Ti.
If
Fl
opens,
all
weld
output
stops
and
pilot
light
2
PU
goes
Out.
2
Fuse
F2
(See
Parts
List
For
Rating)
F2
protects
the
24
volts
ac
winding
of
transformer
Ti.
If
F2
opens,
all
weld
output
stops.
Ref.
57.
154
629-A
Figure
4-1.
Fuse
Location
OM-157
066
Page
8
4-3.
WIre
Drive
Assembly
Maintenance
READ
SAFETY
BLOCKS
at
start
of
Section
4
before
proceeding.
Turn
OFF
unit
and
disconnect
input
power.
1
Wire
Spool
2
Gun
Contact
Tube
Cut
welding
wire
off
at
contact
tube.
Retract
wire
onto
spool
and
se
cure.
3
Drive
Roll
Alignment
Bolt
Turn
in
or
out
until
groove
lines
up
with
wire
guide.
4
Drive
Roll
5
Wire
Inlet
Guide
Remove
guide by
pressing
on
barbed
area
or
cutting
off
one
end
near
housing
and
pulling
it
out
of
hole.
Push
new
guide
into
hole
from
rear
until
it
snaps
in
place.
6
Pressure
Roll
Arm
7
Cotter
Pin
8
Pin
9
Screw
10
Beanng
Remove
bearing
as
shown.
Install
new
bearing
and
secure
with
screw.
Reinstall
am,
onto
pin
and
secure
with
cotter
pin.
Thread
welding
wire
(see
Section
2-6).
Close
door.
Tools
Needed:
Ret
ST.154
626
/
SA-145
763
/
ST-154
633
Figure
4-2.
WIre
Drive
Assembly
Maintenance
OM-157066Page9
4-4.
Gun
Maintenance
Figure
4-3.
Gun
Maintenance
Turn
OFF
unit
and
disconnect
input
power.
1
Wire
Spool
Cut
welding
wire
off
at
contact
tube.
Retract
wire
onto
spool
and
se
cure.
2
Gun
Securing
Knob
Loosen
knob and
remove
gun
and
trigger
plug.
3
Nozzle
4
Contact
Tube
5
Contact
Tube
Adapter
6
Head
Tube
7
Setscrew
8
Wire
Outlet
Guide
Disassemble
gun
as
shown.
9
Liner
Pull
liner
from
this
end.
Blow
gun
casing
out
with
compressed
air.
Insert
new
liner
into
gun
casing.
The
liner
end
covered
with
clear
tubing
goes
to
the
head
tube.
Reinstall
guide
so
that
1/8
in.
(3
mm)
of
liner
sticks
Out.
Hand
tight
en
guide,
and
then
tighten
two
full
turns
more.
Cut
liner
off
so
that
1/2
in.
(13
mm)
sticks
out
of
head
tube.
Trim
clear
tubing
off
1/4
in.
(6.3
mm)
from
end
of
liner.
Tighten
setscrew
to
secure
liner
in
head
tube.
Overtightening
set
screw
crushes
liner
and
causes
wire
feed
problems.
Reassemble
gun.
Reinstall
gun
(see
Section
2-4).
Thread
welding
wire
(see
Section
2-6).
Close
door.
Ref.
ST.154
624
/
ST.145
418-C
/
Ref.
ST.150
438.A
____
READ
SAFETY
BLOCKS
at
start
of
I
~
SectIon
4
before
proceeding
FLYING
METAL
CHIPS
AND
DIRT
can
cause
injury
and
damage
equipment.
Point
gun
away
from
people
and
in
a
safe
direction
when
blowing
out
with
compressed
air.
swar~l0
1
10/91
2
5
6
7
9
Tools
Needed:
3/8
in.
OM-157
066
Page
10
4-5.
Troubleshooting
READ
SAFETY
BLOCKS
at
start
of
SectIon
4
before
proceeding.
Section
2-5
4.2
2~5
2-4
No
weld
output:
wire
does
not
feed;
fan
motor
continues
to
run
and
pilot
light
PU
is
off.
..i__4.,
I
No
weld
output:
wire
feeds.
-~
Connect
work
clamp
to
get
good
metal
to
metal
contact
Replace
contact
tube.
Figure
3-2
-~
4.4
Low
weld
output.
Wire
Drive/Gun
Trouble
Electrode
wire
feeding
stops
during
-.
welding.
H
Connect
unit
to
proper
input
voltage
or
check
for
low
line
voltage
..~
2.5
~I_G2O
BIA
SIB
SECTION
5
ELECTRICAL
DIAGRAMS
Welding
Trouble
I
No
weld
output:
wire
does
not
feed.
Secure
power
cord
plug
in
receptacle.
Remedy
Reset
circuit
breaker
CB1.
Replace
fuse
Fl
and/or
F2
Replace
building
line
fuse
or
reset
circuit
breaker
if
open
Secure
gun
trigger
plug
in
receptacle
or
repair
leads,
or
replace
trigger
switch.
Thermostat
TP1
open
(overheating).
Allow
fan
to
run;
the
thermo
stat
will
close
when
the
unit
has
cooled.
Straighten
gun
cable
and/or
replace
damaged
parts.
Adjust
drive
roll
pressure.
Readjust
hub
tension.
Replace
contact
tube
if
blocked.
Clean
or
replace
wire
inlet
guide
or
liner
if
dirty
or
plugged.
Replace
drive
roll
or
pressure
bearing
if
worn
or
slipping
Secure
gun
trigger
plug
in
receptacle
or
repair
leads,
or
replace
trigger
switch.
Check
and
replace
Fl
and/or
F2.
Check
and
clear
any
restrictions
at
dnve
assembly
and
liner
Have
nearest
Factory
Authorized
Service
Station
check
drive
motor.
Figure
5-1.
Circuit
Diagram
For
Welding
Power
Source
OM.157
066
Page
11
NOTES
OM-157
066
Page
12
Fig
6-3
C
2
7
5
6
)
I.
13
14
,
1
-1
Fig
6-2
(I)
m
C)
0
z
a)
I
Cl)
Cl)
-1
F
I-
21
19
J
8
ST-157
073
Figure
6-1.
Main
Assembly
Parts
For
Main
Assembly
Enclosure
Panel
Housing
Rcpt
&
Sockets
Terminal,
female
Housing
Plug
&
Pins
Terminal,
male
Baffle
w/Cmpts
Transformer,
200/230
Coil
Transformer.
200/230/460
Coil
Stabilizer
Rear
Panel
wlCmpts
Fan
Motor
Fan
Blade
Speed
Nut
Gas
Valve
Nylon
Nut,
.750
Hose
Hose
Clamp
Rectifier
Capacitor
Diode,
RP
Diode,
SP
Washer.
.750
Half
Nut,
.750-16
Thermostat.
NC
026
947
Stand-Off
152
862
Grommet
009
970
Rectifier
Bracket
143810
RearPanel
057
478
Tank
Bracket
044 426
Cable
Clamp
8
022
617
Cylinder
Chain
9
146165
SidePanel,LH
10
151
187
Latch
11
146167
SidePanel
12
134
464
Warning
Label
13
#151
250
Wrapper
14
153
237
Cord
Set,
200/230
model
14
153
426
Cable,
200/230/460
model
23
15
146161
Base
16
135390
Axle
17
070799
Wheel
18
121
614
Retaining
Ring
19
091
685
Resistor
20
605741
Clip
21
008
999
Caster
22
Front
Panel
w/Cmpts
027
645
Light
155348
Rheostat
097
924
Knob
048
282
Receptacle
w/Sockets
Item
Part
No. No.
Description
079
534
Terminal,
female
128
755
Switch,
DPST
153
197
Selector
Switch
148
956
Switch
Handle
120
376
Rocker
Switch
152
626
Front
Panel
155
418
Front
Control
Panel
155
398
Control
Plate
154
251
Nameplate
154
432
Cover,
module
opening
057357
Bushing,
1.l25mtg
143974
Handle
154
596
Cap,
handle
156
270
MWG-21C
Gun,
(Fig
6-2)
144
548
Consumables
Label
144108
Gas
Hose
600318
Weld
Cable
130
750
Ground
Clamp
039
778
Receptacle,
50A
250V
(200/230
model)
+When
ordering
a
component
originally
dis
playing
a
precautionary
label,
the
label
should
also
be
ordered.
Be
sure
to
provide
Model
and
Serial
Number
when
ordering
replacement
parts.
Item
Part
No.
No.
1
152669
2
081
960
3
086281
4
082063
5
082241
6
146
426
6
146425
7
087300
7
071
825
7
054202
7
054
201
8
149146
9
144344
10
089902
11
079974
12
120164
13
154731
14
149927
2
081
960
3
086281
15
128758
16
112884
17
091602
18
049312
19
149
278
20
128769
19
149279
20
120995
19
149280
20
120995
21
079878
079
535
21
22
048834
23
604
525
OPTIONAL
I-lead
Tube
Kit
Retaining
Ring
Hose
Nut,
conduit
Insulator
Adapter.
023
Adapter,
.030045
Contact
Tube,
.023
Contact
Tube,
.030
Contact
Tube,
.035
Contact
Tube,
.045
Nozzle,
.625
art
Cable/Conduit
Terminal
0-Ring,
.500
Trigger
Switch
Assembly
Set
Screw
Handle
Retaining
Ring
Hose
Locking
Ring
Strain
Relief,
extension
Strain
Relief,
cable
Locking
Ring
Liner
Kit,
.023/025
Wire
Guide.
.023
Liner
Kit.
.030/035
Wire
Guide.
.030045
Liner
Kit,
.045
Wire
Guide
.030045
Housing
Plug
&
Pins
Terminal,
male
Clamp
Cable
NOTE:
All
items
indented
by
a
dot(s)
are
included
with
the
item
listed
directly
above
Item
Part
Item
Part
No.
No.
Description
No.
No.
Description
1
146168
2
083
526
009
418
3
072
802
009419
4
Fig
6-3
5
153147
152
734
5
153425
153
424
6 081
716
7
148808
150
783
049399
116996
605
227
134
834
149332
152
742
048
420
037957
037 956
605
886
605
884
604
515
8
4\
Description
~g
13
20~
17
51.155768
Figure
6-2.
MWG-21
C
Gun
(FIg
6-1
item
23)
OM-157
066
Page
14
7.
P
Figure
6-3.
Baffle
w/Cmpts
(Fig
6-1
Item
4)
NOTE:
All
items
indented
by
a
dot(s)
are
included
with
the
item
listed
directly
above.
ST-155
609
Item
Part
No. No.
Description
127232
Drive
Assembly
1
092 237
Knob
2
089477
Spring
3
085
244
Cupped
Washer
4
089
562
Fastener
5
010
224
Spring
Pin
6
090416
HingePin
7
124
817
Drive
Housing
8
124778
1-Knob
9
151
828
Cotter
Hair
Pin
10
112031
PressureLever
11
111
523
Bearing
12
124
818
Drive
Roll,
combination
12
087
130
Drive
Roll,
.023
13
092865
Key
14
124
820
Hub,
drive
roll
15
079 625
Spring
Washer
16
605 308
Retaining
Ring
17
058
549
Wire
Guide,
1/16
17
056
193
Wire
Guide,
.023045
18
021
469
Danger
Label
Item
Part
J
No.
No.
Description
19
144933
Access Door
20
027
645
Ught
21
046685
Vanstor
22
035
704
Rectifier
23
058
428
Hub,
spool
24
057
745
Spring,
2.430
CD
25
058628
Brake
Washer
26
010
191
Fiber
Washer
27
057
971
Keyed
Washer
28
057
543
Spring,
.845
00
29
605
941
Flat
Washer
30
085980
Nut
31
058
427
Retaining
Ring
32
083
431
Circuit
Breaker
33
152631
Baffle
34
083
147
Grommet
35
082
902
Strip,
mtg
center
38
082
907
Angle,
mtg
RH
37
156
517
Capacitor
38
082
875
Angle,
mtg
LH
39
134163
Relay,24/12OVAC
40
000
174
Relay,
24VAC
I
Item
Part
J
No.
No.
Description
41
072 253
Connection
Stud
42
114
780
Contactor
114786
Link
43
*~73
426
Fuse,
slo-blo
5A
44
*085874
Fuse,
slo-blo
1OA
45
098
376
Fuse
Holder
46
152
621
Terminal
Assembly,
chgovr
47
153
322
Terminal
Assembly,
pri
2V
47
153
427
Terminal
Assembly,
pri
3V
038618
Link
48
010199
Tubing
49
039 047
Output
Terminal,
red
50
039
046
Output
Terminal,
black
51
071 971
Cover
52
152632
Motor
Bracket
53
122741
Motor
54
130
365
Insulator
OPTIONAL
*R~mmended
Spare
Parts
Be
sure
to
provide
Model
and
Serial
Number
when
ordering
replacement
parts.
12
36
53
51
41
46
49
48
47
OM-157
066
Page
15
OM-157
066
Page
16
Suggested
Weld
Parameters
Wire
Type.
Shielding
Gas,
And
Flow
Rate
Wire
Diameter
(inch)
Operator
Control
Settings
Material
Thickness
5/16
in.
1/4
in.
3/16
in.
10
ga.
12
ga.
14
ga.
16
ga.
18
ga.
2Oga.
22
ga.
24
ga.
Mild
Steel
ER7OS-6
20th
~
.023
Volt
Tap
LT5
LT4
LT4
LT3
LT3
LT3
LT3
LT3
Feed
Speed%
Low
Range/Full
Range
Full
90
Full
80
Low
86
Low
70
Low
60
Low
55
Low
46
Low
40
.030
Volt
Tap
LT6
LT6
LT5
LT4
LT4
LT4
LT3
LT3
LT3
LT3
Feed
Speed%
Low
Range/Full
Range
Full
75
Full
65
Low
90
Low
90
Low
70
Low
55
Low
40
Low
28
Low
24
Low
20
.035
Volt
Tap
LT6
LT6
LT5
LT5
LT4
LT3
LT3
LT2
LT2
Feed
Speed%
Low
Range/Full
Range
Full
40
Full
35
Low
85
Low
80
Low
55
Low
50
Low
35
Low
20
Low
10
Mild
Steel
ER7OS-6
75%
Ar
25%
CO2
20
cfh
.023
Volt
Tap
114
LT4
LT3
LT3
113
LT2
LT2
LT2
Feed
Speed%
Low
Range/Full
Range
Full
100
Full
90
Low
95
Low
84
Low
76
Low
52
Low
48
Low
44
.030
Volt
Tap
LT6
LT6
LT5
LT4
LT3
LT3
LT2
LT2
LT2
LT2
Feed
Speed%
Low
Range/Full
Range
Full
100
Full
72
Full
70
Low
86
Low
80
Low
70
Low
50
Low
40
Low
35
Low
26
.035
Volt
Tap
LT6
LT6
LT5
LT5
LT4
LT3
LT3
LT2
LT2
Feed
Speed%
Low
Range/Full
Range
Full
82
Full
75
Low
100
Low
90
Low
80
Low
75
Low
60
Low
42
Low
35
Stainless
Steel
308L
HeArCO2
20
cfh
.030
Volt
Tap
LT5
LT4
LT4
LT3
1T3
Feed
Speed%
Low
Range/Full
Range
Full
62
Low
68
Low
65
Low
54
Low
50
.035
Volt
Tap
LT5
LT4
LT4
LT3
LT3
Feed
Speed%
Low
Range/Full
Range
Low
90
Low
70
Low
58
Low
40
Low
38
.
Flux
Cored
E71T-GS
(No
Gas)
.030
Volt
Tap
LT3
LT3
LT2
LT2
LT1
LT1
Feed
Speed%
Low
Range/Full
Range
Low
85
Low
80
Low
56
Low
40
Low
32
Low
22
.035
Volt
Tap
LT4
LT4
LT3
LT2
LT2
LT1
Feed
Speed%
Low
Range/Full
Range
Low
80
Low
65
Low
52
Low
44
Low
38
Low
32
.045
Volt
Tap
LT6
LT6
LT5
LT4
LT3
LT2
LT2
Feed
Speed%
Low
RangelFull
Range
Low
ioo
Low
90
Low
80
Low
60
Low
45
Low
35
Low
30
Not
Recommended
s-156
169
LI
=
Low
Tap
Page is loading ...
Page is loading ...
  • Page 1 1
  • Page 2 2
  • Page 3 3
  • Page 4 4
  • Page 5 5
  • Page 6 6
  • Page 7 7
  • Page 8 8
  • Page 9 9
  • Page 10 10
  • Page 11 11
  • Page 12 12
  • Page 13 13
  • Page 14 14
  • Page 15 15
  • Page 16 16
  • Page 17 17
  • Page 18 18
  • Page 19 19
  • Page 20 20
  • Page 21 21
  • Page 22 22

Miller AUTO ARC 255 Owner's manual

AUTO ARC 255
Miller
Brand
Miller
Model
AUTO ARC 255
Category
Welding System
Type
Owner's manual
This manual is also suitable for

The Miller AUTO ARC 255 is a versatile welding power source with a variety of features that make it ideal for both home and professional use. It offers precise control over the welding process, allowing users to achieve high-quality welds on a variety of metals. With its user-friendly interface and durable construction, the AUTO ARC 255 is an excellent choice for anyone looking for a reliable and powerful welding machine.

Download PDF
report

Ask a question and I''ll find the answer in the document

Finding information in a document is now easier with AI

Related papers

Other documents