Miller Trailblazer 251 Owner's manual
- Category
- Welding System
- Type
- Owner's manual
This manual is also suitable for
Miller Trailblazer 251 is a versatile welding generator designed for professional welding applications. It offers a broad range of welding processes, including SMAW, FCAW, GMAW, and GTAW, making it suitable for various welding tasks. With a maximum output of 250 amps and 25 volts, it delivers ample power to handle demanding welding jobs. The Trailblazer 251 is powered by an Onan P220 air-cooled engine, ensuring reliable performance even in challenging conditions. It also features a user-friendly front panel with intuitive controls for precise welding adjustments.
Miller Trailblazer 251 is a versatile welding generator designed for professional welding applications. It offers a broad range of welding processes, including SMAW, FCAW, GMAW, and GTAW, making it suitable for various welding tasks. With a maximum output of 250 amps and 25 volts, it delivers ample power to handle demanding welding jobs. The Trailblazer 251 is powered by an Onan P220 air-cooled engine, ensuring reliable performance even in challenging conditions. It also features a user-friendly front panel with intuitive controls for precise welding adjustments.
Miller
April
1996
Effective
With
Form:
OM-485
Serial
No.
TEMPORARY
OWNERS
MANUAL
Trailblazerfi
251
CCICV
AC/DC
Welding
Generator
For
SMAW,
FCAW,
GMAW,
GTAW
Welding
Welding
Mode
Nominal
OpenCircuit
Voltage
-
Rated
Welding
Output
Amperage
Range
In
CC
Mode
Voltage
Range
In
CV
Mode
Auxiliary
Power
Rating
Fuel
Capacity
Engine
CC/AC
66
250
A,
25
V,
100%
Duty
Cycle
40
300
10
45
Single-Phase,
4
kVA/kW,
33/16.5
A,
120/240
VAC,
60
Hz
8.5
gal
(32
L)
Onan
P220
Air-Cooled,
Two-Cylinder,
Four-Cycle,
20
HP
Gasoline
Engine
CC/DC
78
CV/DC
46
For
use
with
field
test
units
only.
Follow
this
manual
and
labels
on
unit
to
safely
install
and
operate
unit.
Manual
is
and
remains
the
property
of
MILLER
Electric
Mfg.
Co.
Return
manual
with
unit.
Additional
information
on
field
test
units
avail
abIE~
from
Factory
Reliability
Dept.
cover_temp
4/95
'
1996
MILLER
Electric
Mig.
co.
PRINTED
IN
USA
TABLE
OF
CONTENTS
SECTION
1
-
SAFETY
PRECAUTIONS
FOR
ARC
WELDING
1
1-1.
Symbol
Usage
1
1-2.
Arc
Welding
Hazards
1
1-3.
Engine
Hazards
2
1-4.
Additional
Installation,
Operation,
And
Maintenance
Hazards
3
1-5.
Principal
Safety
Standards
3
1-6.
EMF
Information
3
SECTION
2DEFINITIONS
4
2-1.
Symbol
Definitions
4
SECTION
3-
INSTALLATION
5
3-1.
Installing
Welding
Generator
5
3-1.
Dimensions,
Weights,
And
Operating
Angles
5
3-2.
Fuel
Consumption
6
3-3.
Engine
Prestart
Checks
6
3-4.
Connecting
The
Battery
7
3-5.
Weld
Output
Terminals
And
Selecting
Cable
Sizes
7
3-6.
Remote
14
Receptacle
Information
8
3-7.
Adjusting
GMAW
Weld
Puddle
Consistency
9
SECTION
4-OPERATING
WELDING
GENERATOR
10
4-1.
Front
Panel
Controls
10
4-2.
Duty
Cycle
11
4-3.
Remote
AmperageNoltage
Control
11
SECTION
5OPERATING
AUXILIARY
EQUIPMENT
12
5-1.
Auxiliary
Power
Receptacles
And
Circuit
Breakers
12
SECTION
6-
MAINTENANCE
AND
TROUBLESHOOTING
13
6-1.
Routine
Maintenance
13
6-2.
Maintenance
Label
14
6-3.
Servicing
Air
Cleaner
15
6-4.
Changing
Engine
Oil,
Oil
Filter,
And
Fuel
Filter
16
6-5.
Adjusting
Engine
Speed
17
6-6.
Overload
Protection
18
6-7.
Inspecting
And
Cleaning
Optional
Spark
Arrestor
18
6-8.
Troubleshooting
19
SECTION
7-
ELECTRICAL
DIAGRAM
21
OM-485
4/96
SECTION
1
-
SAFETY
PRECAUTIONS
FOR
ARC
WELDING
sal
ety_romi
4/95
1-1.
Symbol
Usage
AA
Means
Warning!
Watch
Out!
There
are
possible
hazards
with
this
A
Marks
a
special
safety
message.
procedure!
The
possible
hazards
are
shown
in
the
adjoining
symbols.
~
Means
NOTE;
not
safety
related.
~
~
This
group
of
symbols
means
Warning!
Watch
Out!
possible
ELECTRIC
SHOCK,
MOVING
I
PARTS,
and
HOT
PARTS
hazards.
Consult
symbols
and
related
instructions
below
for
necessary
I
actions
to
avoid
the
hazards.
Arc
Welding
Hazards
The
symbols
shown
belo*
are
used
throughout
this
manual
to
call
attention
to
and
identify
possible
hazards.
When
you
see
the
symbol,
watch
out,
and
follow
the
related
instructions
to
avoid
the
hazard.
The
safety
information
given
below
is
only
a
summary
of
the
more
complete
safety
information
found
In
the
Safety
Standards
listed
in
Section
1-5.
Read
and
follow
all
Safety
Standards.
Only
qualified
persons
should
install,
operate,
maintain,
and
repair
this
unit.
During
operation,
keep
everybody,
especially
children,
away.
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
big
enough
to
prevent
any
physical
contact
with
the
work
or
ground.
4.
Disconnect
input
power
or
stop
engine
before
installing
or
servicing
this
equipment.
Lockout/tagout
input
power
according
to
OSHA
29
CFR
1910.147
(see
Safety
Standards).
5.
Properly
install
and
ground
this
equipment
according
to
its
Owners
Manual
and
national,
state,
and
local
codes.
6.
Always
verify
the
supply
ground
check
and
be
sure
that
input
cower
cord
around
wire
is
crocerlv
connected
to
around
terminal
in
disconnect
box
or
that
cord
plug
is
connected
to
a
properly
grounded
receptacle
outlet.
7.
When
making
input
connections,
attach
proper
grounding
conductor
first
double-check
connections.
8.
Frequently
inspect
input
power
cord
for
damage
or
bare
wiring
replace
cord
immediately
if
damaged
bare
wiring
can
kill.
9.
Turn
off
all
equipment
when
not
in
use.
10.
Do
not
use
worn,
damaged,
undersized,
or
poorly
spliced
cables.
11.
Do
not
drape
cables
over
your
body.
12.
If
earth
grounding
of
the
workpiece
is
required,
ground
it
directly
with
a
separate
cable
do
not
use
work
clamp
or
work
cable.
13.
Do
not
touch
electrode
if
you
are
in
contact
with
the
work,
ground,
or
another
electrode
from
a
different
machine.
14.
Use
only
well-maintained
equipment.
Repair
or
replace
damaged
parts
at
once.
Maintain
unit
according
to
manual.
15.
Wear
a
safety
harness
if
working
above
floor
level.
16.
Keep
all
panels
and
covers
securely
in
place.
17.
Clamp
work
cable
with
good
metal-to-metal
contact
to
workoiece
or
worktable
as
near
the
weld
as
cractical.
RNING
ARC
RAYS
can
burn
eyes
and
skin;
ARC
RAYS
NOISE
can
damage
heartng;
FLYING
~
SLAG
OR
SPARKS
can
injure
eyes.
2.
Wear
a
welding
helmet
fitted
with
a
proper
shade
of
filter
to
protect
your
face
and
eyes
when
welding
or
watching
(see
ANSI
Arc
rays
from
the
welding
process
produce
intense
Z49.
1
and
Z87.
1
listed
in
Safety
Standards).
visible
and
invisible
(ultraviolet
and
infrared)
rays
that
can
burn
eyes
and
skin.
Noise
from
some
3.
Wear
approved
safety
glasses
with
side
shields.
processes
can
damage
hearing.
Chipping,
grinding,
and
welds
cooling
throw
off
pieces
of
4.
Use
protective
screens
or
barriers
to
protect
others
from
flash
metal
or
slag.
and
glare;
warn
others
not
to
watch
the
arc.
NOISE
5.
Wear
protective
clothing
made
from
durable,
flame-resistant
1.
Use
approved
ear
plugs
or
ear
muffs
if
noise
level
is
high.
material
(wool
and
leather)
and
foot
protection.
FUMES
AND
GASES
can
be
hazardous
5.
Work
in
a
confined
space
only
if
it
is
well
ventilated,
or
while
to
your
health.
wearing
an
air-supplied
respirator.
Always
have
a
trained
~I
Welding
produces
fumes
and
gases.
Breathing
watchperson
nearby.
Welding
fumes
and
gases
can
displace
air
these
fumes
and
gases
can
be
hazardous
to
your
and
lower
the
oxygen
level
causing
injury
or
death.
Be
sure
the
health.
breathing
air
is
safe.
6.
Do
not
weld
in
locations
near
degreasing,
cleaning,
or
spraying
1.
Keep
your
head
out
of
the
fumes.
Do
not
breathe
the
fumes.
operations.
The
heat
and
rays
of
the
arc
can
react
with
vapors
to
form
highly
toxic
and
irritating
gases.
2.
If
inside,
ventilate
the
area
and/or
use
exhaust
at
the
arc
to
remove
welding
fumes
and
gases.
7.
Do
not
weld
on
coated
metals,
such
as
galvanized,
lead,
or
3.
If
ventilation
is
poor,
use
an
approved
air-supplied
respirator.
cadmium
plated
steel,
unless
the
coating
is
removed
from
the
4.
Read
the
Material
Safety
Data
Sheets
(MSDS5)
and
the
weld
area,
the
area
is
well
ventilated,
and
if
necessary,
while
manufacturers
instruction
for
metals,
consumables,
coatings,
wearing
an
air-supplied
respirator.
The
coatings
and
any
metals
cleaners,
and
degreasers.
containing
these
elements
can
give
off
toxic
fumes
if
welded.
OM-485
Page
1
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.
1.
Protect
compressed
gas
cylinders
from
excessive
heat,
mechanical
shocks,
slag,
open
flames,
sparks,
and
arcs.
2.
Install
cylinders
in
an
upright
position
by
securing
to
a
stationary
support
or
cylinder
rack
to
prevent
falling
or
tipping.
3.
Keep
cylinders
away
from
any
welding
or
other
electrical
circuits.
4.
Never
drape
a
welding
torch
over
a
gas
cylinder.
5.
Never
allow
a
welding
electrode
to
touch
any
cylinder.
6.
Never
weld
on
a
pressurized
cylinder
explosion
will
result.
7.
Use
only
correct
shielding
gas
cylinders,
regulators,
hoses,
and
fittings
designed
for
the
specific
application;
maintain
them
and
associated
parts
in
good
condition.
8.
Turn
face
away
from
valve
outlet
when
opening
cylinder
valve.
9.
Keep
protective
cap
in
place
over
valve
except
when
cylinder
is
in
use
or
connected
for
use.
10.
Read
and
follow
instructions
on
compressed
gas
cylinders,
associated
equipment,
and
CGA
publication
P-i
listed
in
Safety
Sta~dards.
WELDING
can
cause
fire
or
explosion.
Welding
on
closed
containers,
such
as
tanks,
drums,
or
pipes,
can
cause
them
to
blow
up.
Sparks
can
fly
off
from
the
welding
arc.
The
flying
sparks,
hot
workpiece,
and
hot
equipment
can
cause
tires
and
burns.
Accidental
contact
of
electrode
to
metal
objects
can
cause
sparks,
explosion,
overheating,
or
fire.
Check
and
be
sure
the
area
is
safe
before
doing
any
welding.
Protect
yourself
and
others
from
flying
sparks
and
hot
metal.
Do
not
weld
where
flying
sparks
can
strike
flammable
material.
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
easily
go
through
small
cracks
and
openings
to
adjacent
areas.
5.
Watch
for
fire,
and
keep
a
fire
extinguisher
nearby.
6.
Be
aware
that
welding
on
a
ceiling,
floor,
bulkhead,
or
partition
can
cause
fire
on
the
hidden
side.
7.
Do
not
weld
on
closed
containers
such
as
tanks,
drums,
or
pipes,
unless
they
are
properly
prepared
according
to
AWS
F4.
1
(see
Safety
Standards).
8.
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.
Wear
oil-free
protective
garments
such
as
leather
gloves,
heavy
shirt,
cuffless
trousers,
high
shoes,
and
a
cap.
12.
Remove
any
combustibles,
such
as
a
butane
lighter
or
matches,
from
your
person
before
doing
any
welding.
1-3.
Engine
Hazards
SPARKS
can
cause
BATTERY
GASES
TO
EXPLODE;
BATTERY
ACID
can
burn
eyes
and
skin.
Batteries
contain
acid
and
generate
explosive
gases.
STEAM
AND
PRESSURIZED
HOT
COOLANT
can
burn
face,
eyes,
and
skin.
It
is
best
to
check
coolant
level
when
engine
is
cold
to
avoid
scalding.
1.
Always
wear
a
face
shield
when
working
on
a
battery.
2.
Stop
engine
before
disconnecting
or
connecting
battery
cables.
3.
Do
not
allow
tools
to
cause
sparks
when
working
on
a
battery.
4.
Do
not
use
welder
to
charge
batteries
or
jump
start
vehicles.
5.
Observe
correct
polarity
(+
and
)
on
batteries
1.
If
the
engine
is
warm
and
checking
is
needed,
follow
steps
2
and
3.
2.
Wear
safety
glasses
and
gloves
and
put
a
rag
over
cap.
3.
Turn
cap
slightly
and
let
pressure
escape
slowly
before
completely
removing
cap.
1.
2.
3.
AA
WARNING
ENGINE
EXHAUST
GASES
can
kill.
1.
Use
equipment
outside
in
open,
well-ventilated
areas.
Engines
produce
harmful
exhaust
gases.
2.
If
used
in
a
closed
area,
vent
engine
exhaust
outside
and
away
from
any
building
air
intakes.
I
ENGINE
FUEL
can
cause
explosion,
Engine
fuel
is
highly
flammable.
fire
or
2.
3.
Do
not
add
fuel
while
smoking
or
if
unit
is
near
any
s
open
flames.
Do
not
overfill
tank
allow
room
for
fuel
to
expand.
parks
or
4.
Do
not
spill
fuel.
If
fuel
is
spilled,
clean
up
before
starting
1.
Sto
p
engine
and
let
it
cool
off
before
checking
or
a
dding
fuel.
engine.
MOVING
PARTS
can
cause
injury.
3.
Have
only
qualified
people
remove
guards
or
covers
for
Moving
parts,
such
as
fans,
rotors,
and
belts
can
cut
fingers
and
hands
and
catch
loose
clothing.
4.
maintenance
and
troubleshooting
as
necessary.
To
prevent
accidental
starting
during
servicing,
disconnect
negative
()
battery
cable
from
battery.
5.
Keep
hands,
hair,
loose
clothing,
and
tools
away
from
moving
1.
Keep
all
doors,
panels,
covers,
and
guards
closed
and
securely
in
place.
6.
parts.
Reinstall
panels
or
guards
and
close
doors
when
servicing
is
2.
Stop
engine
before
installing
or
connecting
unit.
finished
and
before
starting
engine.
OM-485
Page
2
1-4.
Additional
lnsta!lation,
Operation,
And
Maintenance
Hazards
MOVING
PARTS
can
cause
injury.
1.
Before
working
of
generator,
remove
spark
plugs
or
injectors
to
keep
engine
from
kicking
back
or
starting.
2.
Block
flywheel
so
that
it
will
not
turn
while
workinr
on
generator
components.
STATIC
ELECTRICITY
can
damage
on
circuit
boards.
1.
Put
on
grounded
wrist
strap
BEFORE
boards
or
parts.
Use
proper
static-proof
bags
and
boxes
to
move,
or
ship
PC
boards.
MAGNETIC
FIELDS
FROM
HIGH
CURRENTS
can
affect
pacemaker
operation.
1.
Pacemaker
wearers
keep
away.
2.
Wearers
should
consult
their
doctor
before
going
near
arc
welding,
gouging,
or
spot
welding
ooerations.
LOW
VOLTAGE
AND
FREQUENCY
CAN
DAMAGE
electrical
equipment
such
as
MOTORS.
1.
Turn
off
or
unplug
equipment
before
starting
or
stopping
engine.
OVERUSE
can
cause
OVERHEATED
EQUIPMENT.
1.
Allow
cooling
period.
2.
Reduce
current
or
reduce
duty
cycle
before
starting
to
weld
again.
3.
Follow
rated
duty
cycle.
TILTING
OF
TRAILER
can
cause
injury.
1.
Use
tongue
jack
or
blocks
to
support
weight.
2.
Properly
install
welding
generator
onto
trailer
accordina
to
instructions
supolied
with
trailer.
I
RNING
READ
INSTRUCTIONS.
1.
Use
only
genuine
MILLER
replacement
parts.
2.
Reinstall
injectors
and
bleed
air
from
fuel
system
according
to
engine
manual.
____________________________
DO
NOT
LET
ENGINE
EXHAUST
SPARKS
FLYING
PIECES
OF
METAL
or
DIRT
can
I
t
~
~l
CAUSE
FIRE.
injure
eyes.
1.
Use
approved
engine
exhaust
spark
arrestor
in
1.
Wear
safety
glasses
with
side
shields
or
required
areas
see
applicable
codes.
shield.
2.
HOT
PARTS
can
cause
severe
burns.
1.
Allow
cooling
period
before
maintaining.
2.
Wear
protective
gloves
and
clothing
when
working
on
a
hot
engine.
BATTERY
ACID
can
BURN
SKIN
AND
I
FALLING
EQUIPMENT
can
cause
serious
EYES.
gas
cylinders,
or
any
other
accessories.
_________
2.
Replace
damaged
ballery.
personal
injury
and
equipment
damage.
1.
Donottip.
I
1.
Use
lifting
eye
to
lift
unit
only,
NOT
running
gear,
__________
2.
Use
equipment
of
adequate
capacity
to
lift
unit.
I
3.
Flush
eyes
and
skin
immediately
with
water
1-5.
Principal
Safety
Standards
Safety
in
Welding
and
Cutting,
ANSI
Standard
Z49.
1,
from
American
Safe
Handling
of
Compressed
Gases
in
Cylinders,
CGA
Pamphlet
Welding
Society,
550
N.W.
LeJeune
Ad,
Miami
FL
33126
P-i,
from
Compressed
Gas
Association,
1235
Jefferson
Davis
Safety
and
Health
Standards,
OSHA
29
CFR
1910,
from
Highway,
Suite
501,
Arlington,
VA
22202.
Superintendent
of
Documents,
U.S.
Government
Printing
Office,
Code
for
Safety
in
Welding
and
Cutting,
CSA
Standard
W117.2,
from
Washington,
D.C.
20402.
Canadian
Standards
Association,
Standards
Sales,
178
Rexdale
Recommended
Safe
Practices
fOr
the
Preparation
for
Welding
and
Boulevard,
Rexdale,
Ontario,
Canada
M9W
1
R3.
Cutting
of
Containers
That
Have
Held
Hazardous
Substances,
Safe
Practices
For
Occupation
And
Educational
Eye
And
Face
American
Welding
Society
Standard
AWS
F4.1,
from
American
Protection,
ANSI
Standard
Z87.1
from
American
National
Standards
Welding
Society.
550
N.W.
LeJeune
Ad,
Miami,
FL
33126
Institute,
1430
Broadway,
New
York,
NY
10018.
National
Electrical
Code,
NFPA
Standard
70,
from
National
Fire
Cutting
And
Welding
Processes,
NFPA
Standard
51
B,
from
National
Protection
Association,
Batterymarch
Park,
Quincy,
MA
02269.
Fire
Protection
Association,
Batterymarch
Park,
Quincy,
MA
02269.
1-6.
EMF
Information
Considerations
About
Welding
And
The
Effects
Of
Low
Frequency
To
reduce
magnetic
fields
in
the
workplace,
use
the
following
Electric
And
Magnetic
Fields
procedures:
The
following
is
a
quotation
from
the
General
Conclusions
Section
of
1.
Keep
cables
close
together
by
twisting
or
taping
them.
the
U.S.
Congress,
Office
of
Technology
Assessment,
Biological
Effects
of
Power
Frequency
Electric
&
Magnetic
Fields
Background
2.
Arrange
cables
to
one
side
and
away
from
the
operator.
Paper,
OTA-BP-E-53
(Washington,
DC:
U.S.
Government
Printing
3.
Do
not
coil
or
drape
cables
around
the
body.
Office,
May
1989):.
. .
there
is
now
a
very
large
volume
of
scientific
findings
based
on
experiments
at
the
cellular
level
and
from
studies
4.
Keep
welding
power
source
and
cables
as
far
away
as
with
animals
and
people
which
clearly
establish
that
low
frequency
practical.
magnetic
fields
can
interact
with,
and
produce
changes
in,
biological
systems.
While
most
of
this
work
is
of
very
high
quality,
the
results
are
5.
Connect
work
clamp
to
workpiece
as
close
to
the
weld
as
complex.
Current
scientific
understanding
does
not
yet
allow
us
to
possible.
interpret
the
evidence
in
a
single
coherent
framework.
Even
more
frustrating,
it
does
not
yet
allow
usto
draw
definite
conclusions
about
About
Pacemakers:
questions
of
possible
risk
or
to
offer
clear
science-based
advice
on
The
above
procedures
are
also
recommended
for
pacemaker
strategies
to
minimize
or
avoid
potential
risks.
wearers.
Consult
your
doctor
for
complete
information.
OM-485
Page
3
SECTION
2-
DEFINITIONS
2-1.
Symbol
Definitions
OM-485
Page
4
SECTION
3-INSTALLATION
3-1.
Installing
Welding
Generator
3-1.
Dimensions,
Weights,
And
Operating
Angles
OM-485
Page
5
3-2.
Fuel
Consumption
r
-i
Fuel
Consumption
Curve
Not
Yet
Available
L.
J
3-3.
Engine
Pr~start
Checks
OM-485
Page
6
3-4.
Connecting
The
Battery
To
reduce
possible
interference,
keep
weld
cables
as
short
as
possible,
close
together,
and
down
low,
such
as on
the
floor.
Locate
welding
operation
100
meters
from
any
sensitive
electronic
equipment.
Be
sure
this
welding
machine
is
installed
and
grounded
according
to
this
manual.
If
interference
still
occurs,
the
user
must
take
extra
measures
such
as
moving
the
welding
machine,
using
shielded
cables,
using
line
filters,
or
shielding
the
work
area.
Weld
Output
Terminals
Do
not
connect
to
CC
and
CV
terminals
at
the
same
time.
Welding
Amperes
Total
Cable
(Copper)
Length
In
Weld
Circuit
Not
Exceeding
100
ft
(30
m)
Or
Less
150ft
200ft
250ft
I
300ft
I
350ft
400
ft
(45
m)
(60
m)
J
(70
m)
(90
m)
(105
m)
1(120
m)
1060%
Duty
Cycle
60100%
Duty
Cycle
10
100%
Duty
Cycle
STICKJTIG
WIRE
(CC)
(CV)
ST-801
534
100
4
4
4
3
2
1
1/0
1/0
150
3
3 2
1
1/0
210
3/0 3/0
200
3
2
1
1/0
210
3/0
4/0 4/0
250
___
2
1
1/0
2/0
3/0
4/0
2-210
2-2/0
300
______
1
1/0
2/0
3/0
4/0
2-2/0
2-3/0
2-3/0
350
1/0
2/0
3/0 4/0
2-2/0
2-3/0
2-3/0
2-4/0
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.
S-0007-D
A
ARC
WELDING
can
cause
Electromagnetic
Interference.
3-5.
Weld
Output
Terminals
And
Selecting
Cable
Sizes
OM-485
Page
7
3-6.
Remote
14
Receptacle
Information
/
The
remaining
sockets
are
not
used.
ST-801
534
REMOTE
14
Soc
ket*
Socket
Information
Circuit
common
for
24
and
115
volts
ac
circuits.
Chassis
common.
24
VOLTS
AC
(3)
OUTPUT
(CONT#CTOR)
A
24
volts
ac.
B
Contact
closure
to
A
completes
24
volts
ac
contactor
control
circuit.
115VOLTSAC
OUTPUT
(~ON1~CTOR)
I
~
115
volts
ac.
J
Contact
closure
to
I
completes
115
volts
ac
contactor
control
circuit.
AN
AMPERAGE
VOLTAGE
C
+10
volts
dc
output
to
remote
control.
D
Remote
control
circuit
common.
E
0
to
+10
volts
dc
input
command
signal
from
remote
control.
GND
G
K
OM-485
Page
8
3-7.
Adjusting
GMAW
Weld
Puddle
Consistency
A
Stop
engine.
Stabilizer
DC-Z
is
factory
connected
to
suit
most
GMAW
applications.
To
change
GMAW
weld
puddle
consistency,
proceed
as
follows:
Remove
right
side
panel.
1
Stabilizer
DC-Z
2
TapslThru5
Starting
from
center
of
DC-Z,
taps
will
be
referred
to
as
1
through
5.
3
Insulation
Sleeve
4
Lead
79
5
Tap
Lead
79
is
connected
to
tap
3.
Cut
cables
ties
as
necessary
to
get
to
lead
79.
Slide
sleeve
up
on
lead
79.
Disconnect
lead
79
from
tap.
To
wet
out
weld
puddle:
Connect
lead
79
to
tap
2,
reusing
hardware.
To
stiffen
weld
puddle:
Connect
lead
79
to
tap
4,
reusing
hardware.
Slide
sleeve
over
new
lead
connection,
and
secure
with
cable
ties.
Install
side
panel.
~
3/8,7/16
in
ST-801
537/
Ret.
ST-18O
801
OM-485
Page
9
SECTION
4-
OPERATING
WELDING
GENERATOR
4-1.
Front
Panel
Controls
4~
WARNING:
ELECTRIC
SHOCK
CAN
KILL
DO
NOT
UXE
AC
OUTPUT
IN
DAMP
AREAS.
IF
MOVE
MENT
IS
CONFiNED.
OR
IF
THERE
ISA
DAN~
OF
FALLiNG.
USE
AC
OUJPUT
ONI.Y
IF
-
REQUIRED
FOR
ThE
WELD-
Duly
CACtI
INS
PRO~SS.
MAX
1
DC
Polarity/AC
Switch
Use
switch
to
select
AC
weld
output
or
polarity
of
DC
weld
output.
A
Do
not
switch
under
load.
2
V/A
Control
Use
control
to
select
weld
voltage
or
amper
age.
Control
may
be
adjusted
while
welding.
3
Process
Selector
Switch
Use
switch
to
select
output
for
weld
process.
A
Do
not
switch
under
load.
4
Engine
Control
Switch
Use
switch
to
start
engine,
select
speed,
and
stop
engine.
In
Run/Idle
position,
engine
runs
at
idle
speed
at
no
load,
and
weld/power
speed
under
load.
In
Run
position,
engine
runs
at
weld/power
speed.
~
Place
switch
in
Run
position
to
operate
most
GMAW
equipment.
5
Engine
Choke
Control
Use
control
to
change
engine
air-fuel
mix.
To
Start:
pull
out
choke
and
turn
Engine
Control
switch
to
Start
position.
Release
switch
and
slowly
push
choke
in
when
engine
starts.
Do
not
crank
engine
while
engine
is
still
turning.
To
Stop:
turn
Engine
Control
switch
to
Off
position.
6
Engine
Hour
Meter
7
Remote
AmperageNoltage
Switch
Use
switch
to
select
front
panel
or
remote
amperage/voltage
control
(see
Section
4-3).
8
Output
(Contactor)
Switch
Use
switch
to
control
remote
contactor
if
connected
to
remote
14
receptacle
RC1
(see
Section
4-3).
A
Weld
output
terminals
are
energized
when
Output
(Contactor)
switch
is
On
and
engine
is
running.
2
DO
NOT
SWITCH
tINDER
LOAD
A
10
______________
DC
POI!~ITY/AC
FINE
ADJUST
EN~?JE
L~C~
RATED
WELD
OUTPUT
cc
cc
cv
DC
DC
72
IS
46
AX
AX
AX
WE WE
WE
IRAS
IIS%
ILE%
WiN
VAX
WiN
r
TUTSLALLLDADE4WEWATTI
MEJTR~
TO FRAME
NOflRE
RACCO~
AU
BAli
L
010
A/V
Q.oui~n
S
Z14
REMOTE
CONTROL
\
\\
AC
POWER
87
Ref.
ST-lao
601-A
OM-485
Page
10
4-2.
Duty
Cycle
100%
Duty
Cycle
at
250
Amperes
Continuous
Welding
I-
-,
Duty
cycle
is
the
percentage
of
10
minutes
that
unit
can
weld
at
rated
load
without
overheating.
A
Exceeding
duty
cycle
can
damage
unit
and
void
warranty.
A/Va
I
ON
I
Adjust
Remote
Control
(SMAW
Only)
Duty
Cycle
Chart
Not
Yet
Available
4-3.
Remote
AmperageNoltage
Control
Remote
14
Receptacle
Rd
Connect
optional
remote
control
to
RC1
(see
Section
3-6).
2
Remote
Amperage
Control
(Optional)
cc~~-
cv
&
E~.LCT~O~
-~
.Oamv.
In
Example:
Process
=
SMAW
Mm
=
25
A
CC/DC
Max
=
170
A
CC/DC
(50%
of
40
to
300
A)
AC
2~$8
*a~.i9
Set
Switches
Max
(170
A
DC)
Set
Polarity
C
Mm
(25
A
DC)
Set
Control
ST-801
534
/
ST-i
80601
/
S-0769
I
S~0774
OM-485
Page
11
SECTION
5-
OPERATING
AUXILIARY
EQUIPMENT
5-1.
Auxiliary
.Power
Receptacles
And
Circuit
Breakers
TOTALA~
WADS
4000
WA~
~
AC
POWER
/
A
Use
GFCI-protected
exten
sion
Cord.
1
l2OVl5AACDuplex
Receptacle
RC1
2
24OV15AACDupIOx
Receptacle
RC2
RC1
and
RC2
supply
60Hz
single-
phase
power
at
weld/power
speed.
Maximum
output
from
RC1
is
3.6
kVAIkW.
Maximum
output
from
RC2
is
4.0
kVAIkW.
3
Circuit
Breakers
CB3
And
CB4
CB3
and
CB4
protect
RC1
from
overload.
If
CB3
or
CB4
opens,
half
of
AC1
does
not
work.
Press
button
to
reset
breaker.
4
Circuit
Breaker
CB5
And
CB6
CB5
and
CB6
protect
RC2
from
overload.
If
CB5
or
CB6
opens,
RC2
does
not
work.
120
volts
may
still
be
present
at
RC2.
~
if
a
circ
wt
breaker
continues
to
open,
contact
Factory
Authorized
Service
Agent.
Combined
output
of
all
receptacles
limited
to
4
kVA/kW
output
of
the
generator.
EXAMPLE:
If
15
A
is
drawn
from
RC1,
only
9
A
is
available
at
RC2:
(l2OVx
15A)+(240Vx9A)=4.0
kVAJkW
5
Auxiliary
Power
While
Welding
Table
Weld
Current
cv,cc
Watts
Current
In
Amperes
120V
240V
250
225
200
150
100
50
0
2200
2750
3250
3300
3800
4000
4000
18.5
23
27
27.5
32
33.3
33.3
9
11.5
13.5
14
16
16.7
16.7
Ret.
ST-180
601
SIMULTANEOUS
WELDING
AND
POWER
See
Owners
Manual
for
additional
information.
S-135
048-B
OM-485
Page
12
SECTION
6-
MAINTENANCE
AND
TROUBLESHOOTING
6-1.
Routine
Maintenance
Repair
Or
Replace
Cracked
Cables.
Recycle
engine
fluids.
fi
20h
25h
lOOh
200h
A
Stop
engine
before
maintaining.
~
See
also
Engine
Manual
and
maintenance
label.
Service
engine
more
often
during
severe
conditions.
500h
l000h
OM-485
Page
13
6-2.
Maintenance
Label
(
Air
Filter
Service
.
.
.
100
hours
or
less
see
Owners
Manual
Air
Filter
Element
....
MILLER
064
617,
Onan
140-2628-01
V
Air
Filter
Wrapper....
MILLER
065
653.
Onan
140-1496
r-i
ri
12
Volt
Battery
BCI
Group
58
+
Cranking
Pe~ormance
at
0~F
(~18DC)
.
.
..
430
Amps
mm.
Valve
Clearance
Cold
In.
. . .
0.005
in
(0.13
mm)
Ex.
. .
0.013
in
(0.33
mm)
A
Spark
Plug
Gap
0.025
in.
(0.6
mm)
,~7
Spark
Plug
Champion
RS17VX
Preterred
or
RS14YC
Use
only
resistor
spark
plugs
and
wires.
OM-485
Page
14
6-3.
Servicing
Air
C~Ieaner
A
Stop
engine.
A
Do
not
run
engine
without
air
cleaner
or
with
dirty
element.
1
Precleaner
Wash
precleaner
with
soap
and
water
solution.
Allow
precleaner
to
air
dry
completely.
Spread
1
tablespoon
SAE
30
oil
evenly
into
precleaner.
Squeeze
out
excess
oil.
2
Element
Replace
element
if
dirty
or
oily.
2
aircleaner3
4/96
ST-156
852
/
S-0759
OM-485
Page
15
6-4.
Changing
Engine
Oil,
Oil
Filter,
And
Fuel
Filter
Stop
engine
and
let
cool.
Oil
Drain
Valve
1/2
lOx
12
in
Hose
Oil
Filter
Change
engine
oil
and
filter
according
to
engine
owners
manual.
Close
valve
and
valve
cap
before
adding
oil
and
run
ning
engine.
Fill
crankcase
with
new
oil
to
full
mark
on
dipstick
(see
Section
6-2).
4
Fuel
Filter
5
Fuel
Line
Replace
line
if
cracked
or
wom.
Install
new
filter.
Wipe
up
any
spilled
fuel.
Start
engine,
and
check
for
fuel
leaks.
Stop
engine,
tighten
connections
as
necessary,
and
wipe
up
fuel.
Ref.
ST-801
532
/
ST-BOO
395-A
/
Ref.
ST-iSO
601
I
S-O842
OM-485
Page
16
6-5.
Adjusting
Engine
Speed
After
tuning
engine,
check
engine
speeds
with
a
tachometer
(see
table).
If
necessary,
adjust
speeds
as
follows:
Start
engine
and
run
until
warm.
Turn
Fine
Adjust
AN
control
to
Max.
Idle
Speed
Adjustment
1
Throttle
Solenoid
2
Mounting
Screw
Loosen
two
mounting
screws.
3
Governor
Arm
4
Carburetor
5
Idle
Speed
Screw
Pull
governor
arm
away
from
carburetor
and
hold
while
making
the
following
adjustment:
Turn
idle
speed
screw
until
engine
runs
at
idle
speed
(see
table).
Release
governor
arm.
Place
Engine
Control
switch
in
Run/Idle
position.
6
Carburetor
Stop
With
solenoid
energized,
slide
solenoid
until
idle
speed
screw
just
touches
carburetor
stop.
Tighten
solenoid
mounting
screws.
7
Governor
Arm
Extension
Check
for
smooth
operation,
and
readjust
solenoid
position
if
necessary.
Weld/Power
Speed
Adjustment
Place
Engine
Control
switch
in
Run
position.
8
Weld/Power
Speed
Rod
9
Locking
Nut
Loosen
nut.
10
Adjustment
Nut
Turn
adjustment
nut
until
engine
runs
at
weld/power
speed.
Tighten
locking
nut.
Stop
engine.
11
Sensitivity
Spring
See
engine
manual
for
governor
sensitivity
adjustment.
ST-800
397
/
Ret,
ST-801
532
.~
2200–lOOrpr
3700–50rpm
1/4,3/8in
OM-485
Page
17
6-6.
Overload
Protection
6-7.
Inspecting
And
Cleaning
Optional
Spark
Arrestor
A
Stop
engine
and
let
cool.
1
Spark
Arrestor
Screen
Clean
and
inspect
screen.
Re
place
spark
arrestor
if
screen
wires
are
broken
or
missing.
ST-801
532
/
Ret.
ST.8O1
206
/
Ref.
ST-i
80
601
1/4
in
OM-485
Page
18
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Miller Trailblazer 251 Owner's manual
- Category
- Welding System
- Type
- Owner's manual
- This manual is also suitable for
Miller Trailblazer 251 is a versatile welding generator designed for professional welding applications. It offers a broad range of welding processes, including SMAW, FCAW, GMAW, and GTAW, making it suitable for various welding tasks. With a maximum output of 250 amps and 25 volts, it delivers ample power to handle demanding welding jobs. The Trailblazer 251 is powered by an Onan P220 air-cooled engine, ensuring reliable performance even in challenging conditions. It also features a user-friendly front panel with intuitive controls for precise welding adjustments.
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