Miller Electric SCE-1A User manual

February
1980
FORM: OM-540A
.tcc
._
,
I.
~
5
Effective
With
Serial
No.
HK321565
MODEL
SCE-1A
SCE-3A
SCE-5A
SCM-lA
SCM-3A
SCM-5A
OWN
E
RS
MANUAL
I11dIER
MILLER
ELECTRIC
MFG. CO.
718
S. BOUNDS ST. P.O.
Box
1079
APPLETON,
WI
54912
USA
NWSA
CODE
NO.
4579
PRINTED IN
U.S.A.

L~
~L~
L
~
L&P
~
LIMITED
WARRANTY
EFFECTIVE:
JUNE
1.
1979
This
warranty
supersedes
all
previous
MILLER
warranties and is
ex
clusive
with
no
other
guarantees
or
warranties
expressed
or
implied.
LIMITED
WARRANTY-Subject
to
the
terms
and
conditions
As
a
matter
of
general
policy
on1y,
Miller
may
honor claims
hereof,
Miller Electric
Mfg.
Co.,
Appleton,
Wisconsin
warrants
submitted
by
the
original
user
within
the
foregoing
periods.
to
its Distributor/Dealer
that
all
new
and
unused
Equipment
(
furnished
by
Miller
is
free
from defect
in
workmanship
and
In
the
case
of Millers breach
of
warranty
or
any
other
duty
material
as
of the time
and
place
of
delivery by
Miller. No
war-
with
respect
to
the
quality
of
any
goods,
the exclusive
remedies
ranty
is made
by
Miller
with
respect
to
engines,
trade
ac-
therefore
shall
be,
at
Millers
option
11)
repair
or
(21
replacement
cessories
or
other
items manufactured
by
others.
Such
or,
where
authorized
in
writing
by
Miller
in
appropriate cases,
(31
engines,
trade accessories
and other
items
are
sold
subject
to
the
reasonable cost
of
repair
or
replacement
at
an
authorized
the
warranties
of
their
respective
manufacturers,
if
any
.
All
Miller service
station
or
141
payment
of
or
credit
for
the
purchase
engines
are
warranted
by
their manufacturer for
one
year
from
price
(less
reasonable
depreciation
based
upon
actual
use)
upon
date
of
original
purchase.
return
of
the
goods
at
Customers
risk
and
expense.
Upon
receipt
of
notice
of
apparent
defect
or
failure,
Miller shall instruct the clai-
Except
as
specified
below,
Millers
warranty
does
not
apply
mant on
the
warranty
claim
procedures
to
be followed.
to
components
having
normal useful life of less
than
one
(1)
year,
such
as
spot
welder
tips, relay
and
contactor
points,
ANY
EXPRESS
WARRANTY NOT
PROVIDED
HEREIN
AND
MILLERMATIC
parts
that
come
in
contact
with the
welding
ANY
IMPLIED
WARRANTY,
GUARANTY
OR
REPRESENTA-
wire
including
nozzles
and
nozzle
insulators where failure does
lION
AS TO
PERFORMANCE,
AND
ANY REMEDY
FOR
not
result
from defect
in
workmanship
or
material.
BREACH OF
CONTRACT
WHICH,
BUT
FOR THIS
PROVISION,
MIGHT ARISE
BY
IMPLICATION,
OPERATION
OF
LAW,
Miller shall be
required
to
honor
warranty
claims
on war-
CUSTOM
OF
TRADE
OR COURSE OF
DEALING,
INCLUDING
ranted
Equipment
in
the
event
of failure
resulting
from
a
defect
ANY
IMPLIED
WARRANTY OF
MERCHANTABILITY
OR OF
within
the
following
periods
from the
date of
delivery
of
Equip-
FITNESS
FOR
PARTICULAR
PURPOSE,
WITH
RESPECT
TO
ment
to
the
original
user:
ANY AND ALL
EQUIPMENT
FURNISHED
BY
MILLER (S EX
CLUDED
AND
DISCLAIMED
BY
MILLER.
1. Arc
welders,
power
sources
and
components
- .
1
year
2.
Original
main
power
rectifiers
3
years
EXCEPT AS
EXPRESSLY PROVIDED
BY MILLER
IN
(labor
-
1
year
onlyl
WRITING,
MILLER
PRODUCTS
ARE INTENDED FOR
3.
All
welding
guns
and
feeder/guns
90
days
ULTIMATE
PURCHASE BY
COMMERCIAL/INDUSTRIAL
4.
All other
Millermatic
Feeders
1
year
USERS
AND
FOR
OPERATION
BY
PERSONS
TRAINED AND
5.
Replacement
or
repair
parts,
exclusive of
labor
.
60
days
EXPERIENCED
IN
THE USE AND
MAINTENANCE OF
6. Batteries
6 months
WELDING
EQUIPMENT
AND
NOT
FOR CONSUMERS OR
CONSUMER USE.
MILLER
WARRANTIES
DO NOT
EXTEND
provided
that
Miller is
notified
in
writing
within
thirty
(30)
days
TO,
AND
NO RESELLER
IS AUTHORIZED
TO
EXTEND
of the
date
of such
failure.
MILLERS
WARRANTIES
TO,
ANY
CONSUMER.
~%
.~, J~
~
J~

TABLE
OF
CONTENTS
Section
No.
Page
No.
SECTION
1

INTRODUCTION
1
-
1.
General
1
1
-
2.
Receiving-Handling
1
1
-
3.
Description
1
1-4.
Safety
1
SECTION 2

INSTALLATION
2-
1.
Electrical
Input
Connections
1
2.
2.
Secondary
Connections
1
2
-
3.
Shielding
Gas
Con
nØctions
1
2
-
4.
Coolant
Connections
2
2
-
5.
Contactor Control
Receptacle
2
2.
6.
Emergency
Stop
Switch
Connections 2
2-
7.
Manual Control Connections
Of
Sequence
C 2
SECTION
3
FUNCTION OF
CONTROLS
3
-
1.
Sequence
Control Function
3
3-
2. Current Control 3
3
-
3. Start
Switch
(SCE/SCM-1A
and
2A)
3
3
-
4.
Weld
Switch
3
3
-
5.
Manual
Control
Of
Sequence
C
4
3-
6.
High-Frequency
Control
4
SECTION
4

SEQUENCE OF OPERATION
4
-
1.
Gas
Tungsten-Arc Welding
(GTAW)
4
4-
2.
Shielded Metal-Arc
Welding
(SMAW)
4
4
-
3.
Shutting
Down 5
SECTION
5
MAINTENANCE
5
-
1.
High
Voltage Capacitors
5
5-
2.
Spark
Gap
Adjustment
5
5
-
3.
Bypass
Panel
6
5
-
4.
Control Circuit Protection 6
SECTION
6
TROUBLESHOOTING
SECTION
7

CERTIFICATION
FOR
HIGH FREQUENCY
ARC
WELDING
EQUIPMENT
7-
1.
General
7
7
-
2.
General
Information
7
7
-
3.
Power
Service
7
7
-
4.
Welding
Machine
7
7
-
5.
Welding
Leads
8
7
-
6.
Wiring
In
The
Vicinity
Of The
Welding
Area
8
7-
7.
Grounds
8
7
-
8.
Metal
Building
8
7
-
9.
Individual Installation
Certification
9
7-10.
Check List
9

SECTION
1
-
INTRODUCTION
Dime
Height
nsions
(Inches)
Width
Depth
Weight
Net
(Pounds)
Shipping
33-1/4
26-1/4
10-3/4
168 230
Figure
1-1.
Specifications
1-1.
GENERAL
This manual has been
prepared
especially
for
use
in
familiar
izing
personnel
with the
design,
installation
operation,
main
tenance,
and
troubleshooting
of this
equipment.
All
informa
tion
presented
herein
should
be
given
careful
consideration
to
assure
optimum performance
of this
equipment.
1-2.
RECEIVING-HANDLING
Prior
to
installing
this
equipment,
clean all
packing
material
from around
the
unit
and
carefully inspect
for
any
damage
that
may
have
occurred
during
shipment.
Any
claims
for loss
or
damage
that
may
have occurred
in
transit
must
be
filed
by
the
purchaser
with
the
carrier.
A
copy
of
the
bill
of
lading
and
freight
bill
will
be
furnished
by
the
carrier
on
request
if
occasion
to
file claim
arises.
When
requesting
information
concerning
this
equipment,
it is
essential
that
Model
Description
and/or
Stock
Number
and
Serial
(or
Style)
Numbers
of
the
equipment
be
supplied.
1-3.
DESCRIPTION
These
Sequence
Controls
are
specifically
designed
to
be
used
in
conjunction
with
an
electric
current
controlled
welding
power
source.
These
Sequence
Controls
provide
five
different
sequences
for either
automatic
or
semi-automatic
operation
of
the
various
welding
processes.
The function
of each
sequence
is
described
in
Section
3,
FUNCTION
OF
CON
TROLS,
in
this
manual.
The SCE
Models
are
equipped
with
electronic
timers
in
sequences
B, C,
and
D.
The
SCM
Models
are
equipped
with
mechanical
timers
in
sequences
B,
C,
and
D.
1-4.
SAFETY
Before
the
equipment
is
put
into
operation,
the
safety
sec
tion
at
the front
of
the
welding
power
source
or
welding
generator
manual
should be read
completely.
This
will
help
avoid
possible
injury
due
to
misuse
or
improper
welding
applications.
The
following
definitions
apply
to
CAUTION,
IMPORTANT,
and
NOTE
blocks
found
throughout
this
manual:
sonnel.
I
IL
1
U
.
Under
this
heading,
installation,
operating,
and
main
tenance
procedures
or
practices
will
be
found
that
if
not
carefully
followed
may
result
in
damage
to
equip
ment.
NOTE
Under
this
heading,
explanatory
statements
will
be
found
that
need
special
emphasis
to
obtain
the
most
efficient
operation
of
the
equipment.
SECTION
2
-
INSTALLATION
2-1.
ELECTRICAL
INPUT
CONNECTIONS
Refer
to
the
Installation Section
of the
welding
power
source
Manual
for
instructions
on
connecting
electrical
input
power
to
the
welding
power
source.
On
the SCE/SCM-1A
and
3A
Models,
inside
the
cabinet
on
the
lower
right
corner
above
the control
transformer,
is
either
a
three
or a
five
pole
terminal
block
with
one
jumper
link
attached.
The
primary
power
supply
to
the
Sequence
Control
is
connected
to
this
block.
The
jumper
link
must
be
connected
for
the
primary
power
supply
voltage
that will
correspond
with
the
primary
power
supply
voltage
of
the
TA-040
107-4
Figure
2-1.
Line
Voltage
Jumper
Link
Arrangement
welding
power
source.
Refer
to
Figure
2-1 for
positioning
of
the
link
for
the
required
operating voltage.
On
the
SCE/SCM-5A,
the control
transformer
which
provides
the
primary
power
to
the
control
is
located
in
the
welding
power
source.
2-2.
SECONDARY
CONNECTIONS
(Figure
2-2)
unit
was
shipped
wh
the
secondary
inte
r
connecting
cables between
the
Sequence
Control
and
welding
power
source
unconnected.
It
is
therefore
necessary
to route
and
secure
the
secondary
inter
connecting
cables
(already
attached to
Sequence
Con
trol) to
the
proper
weld
output
terminals
on
the
welding
power
source.
The
secondary welding
cables
should
only
be
attached
to
the
output
terminals
on
Sequence
Control
to
achieve
proper
operation
of
this
Refer
to Installation
Section of the
welding
power
source
Owners
Manual
for
proper
weld
cable size.
The
secondary
terminals
on
the
Sequence
Control
are
labeled
ELECTRODE
and
WORK.
Connect
the
electrode holder
cable
to the
terminal
marked
ELECTRODE
and
the work
cable to
the
terminal
marked WORK.
2-3.
SHIELDING
GAS CONNECTIONS
(Figure
2-2)
These connections
are
located
on
the
front
panel
and
are
labeled
IN-GAS-OUT.
The
connections
have
a
right-hand,

Under this
heading, installation,
operating,
and
main
tenance
procedures
or
practices
will he
found that
if
not
carefully
followed
may
create a
hazard
to per-
U
I
U
I
230/460
VOLTS

~
230
460
208/230/460
VOLTS


208
230 460
230/460/575
VOLTS
00
000
230
460 575
OM-540
Page
1

5/8-18
female
thread.
Connect
the
hose from
the
shielding
gas
supply
to
the connection
labeled IN. Connect
the
hose
from the
electrode holder
to the
connection labeled
OUT.
2-4.
COOLANT
CONNECTIONS
(Figure
2-2)
These
connections
are
located
on
the
front
panel
and
are
labeled
IN-COOLANT-OUT.
The
connections have
a
left-
hand,
5/8-18
female
thread.
Connect
the hose
from the
coolant
supply
to
the
connection labeled
IN.
Connect
the
hose
from the
electrode
holder
to
the
connection
labeled
OUT.
This
three-prong,
twistlock
receptacle provides
contactor
control
facilities.
Either
a
remote
hand
or
foot
switch
can
be
used
in
conjunction
with this
receptacle.
2-6.
EMERGENCY
STOP SWITCH
CONNECTIONS
(Fig
ures
2-3
and
3-2)
A
five-pole
terminal
block with
two
jumper
links
attached,
located
on
the inside
lower left
corner
of
the
cabinet,
provides
a
means
of
emergency
stop
connections of
weld
sequences
B, C,
or
0.
If
it
is
desirable
to
connect
an
emergen
cy
stop
switch
in
the
circuit,
remove
the
jumper
link
that is
connected
across
the
fourth
and
fifth
terminals,
counting
left
to
right.
Connect
a
normally-closed
switch
to
the terminals
from which
the link
was
removed.

If
a
portable,
self-contained coolant
system
is used
with
this
unit,
ensure
that
the coolant
pump
has
bypass capability
to
avoid
possible
damage
to
the
motor
when the coolant
valve
closes
and
coolant
flow

stops.
2-5. CONTACTOR CONTROL
RECEPTACLE
(Figure
2-2)
Figure
2-2.
Front
Panel
View
With
the
WELD
switch
in
the
AUTOMATIC
position,
weld
sequences
B,
C,
or
D
may
be
interrupted
at
any
time
by
opening
the
emergency
stop
switch.
Opening
of this switch
will
initiate
sequence
E
(post-flow
time).
2-7. MANUAL
CONTROL
CONNECTIONS
OF
SE
QUENCE
C
(Figures
2-3
and
3-2)
A
five-pole
terminal
block,
with
two
jumper
links
attached,
located
on
the
inside
lower left
corner
of
the
cabinet,
provides
a
means
of
external
switch
control
of
sequence
C.
To
connect
an
external
switch for
manual
control
of
sequence
C,
remove
the
jumper
link
connected
across
the
first
and
second terminals
counting
left
to
right.
Connect
a
normally-open
switch
to
the
terminals
from which
the
link
was
removed.
SECTION
3-
FUNCTION
OF
CONTROLS
WELD
SWITCH
~
~
$
I
DC
AMMETER
~
L~
WORK
TERMINAL
HIGH-FREQUENCY
SWITCH
START SWITCH
(ONLY
ON
SCE/SCM-1 A)

GAS
CONNECTIONS
COOLANT
CONNECTIONS
C
ON
TA
CTO
R
CONTROL
RECEPTACLE
ELECTRODE
TERMINAL
TA-OlO
566
Figure
2-3.
Terminal
Block
For
External
Switch
Operation
PRE-FLOW
OF
ANT
GAS
&
Ui
CWFLD
Ui
a.
S
POST-FLOW
OF
GAS
&
COOLANT
DFINISH
~
E
~i~I77~ffl7~A #~
~
~START
~
\~ ~
FINISH
TIME
Figure
3-1.
Sequence
Time
Chart
TA-040
107-6
Page
2

3-1.
SEQUENCE
CONTROL
FUNCTION
(Figure
3-1)
This
Sequence
Control
is
a
five
sequence automatic
control
designed
for
Gas
Tungsten-Arc
Welding
)GTAW).
The
function
of each
sequence
is
as
follows:
PRE-FLOW:
gas
and
coolant;
adjustable
mechanical
time
of
1/4
to
15
seconds.
START
current:
adjustable
control
and
timer
preset
magnitude
of
current
and
time.
WELD
current:
adjustable
control
and timer
provide
exact
values
of
current
and
time.
Sequence
can
be
manually
controlled.
Sequence
D:
SLOPE current:
adjustable
control
and
timer
are
preset
to
determine
magnitude
and
time
duration
of
current
at
end
of
weld.
Sequence
E:
POST-F
LOW:
gas
and
coolant;
adjustable
mechanical
time
sequence
of 2
seconds
to
3
minutes.
3-2.
CURRENT
CONTROL
(Figure
3-2)
The
welding
current
for
sequences
B,
C.
and
D
is
governed by
the
setting
of the
control
immediately
above
each
sequence
timer.
These
controls
are
calibrated
in
percentages
and
function
as
remote
controls,
in
that
they
are
fine
amperage
adjustments
of the
AMPERAGE
ADJUSTMENT
control
on
the
welding
power
source.
The
REMOTE
AMPERAGE
CONTROL switch
on
the
welding
power
source
must
be
in
the
STANDARD
position
for
proper
operation
of
the
Sequence
Control.
NOTE
The
AMPERAGE
ADJUSTMENT
control
on
the
welding
power
source
must
be
in
the
one
hundred
percent
(maximum)
position
for
maximum
control
of
the
selected
range.
value
from
the
minimum
to
the maximum of the
selected
current
range
on
the
welding
power
source.
C.
Slope
Weld
Amperage
Control
(Sequence
D)
The
SLOPE
control is
provided
for
selecting
the
slope
weld
current
value.
The control is
adjustable
and
can
be
set
for
any
value from the
minimum
to
the
maximum
of
the
selected
current
range
on
the
welding
power
source.
For
a
normal
finish the
control should
be
set
for
a
value less
than the
WELD
(sequence
C)
setting.
3-3.
START
SWITCH
(SCE/SCM-1A)
(Figure
2-2)
This
switch
provides
a
choice of
selecting
either
a
normal
or
a
fast
start
of
sequence
B
(START
weld).
A.
Normal
Position
With
the switch
in the
NORMAL
position,
the
starting
current
will
start at
a
value less
than the
setting
of
the
START
weld
amperage
control,
but
will
rapidly
increase
to
the
setting
of
the
START
weld
amperage
control.
B.
Fast
Position
With
the
switch
in
the
FAST
position,
the
starting
current
will
start
at
the
value of
the
START
weld
amperage
setting.
3-4.
WELD SWITCH
(Figure
2-2)
This
switch
provides
a
choice
of
selecting
either
an
automatic
or
semi-automatic
operation
of the
Sequence
Control.
A.
Automatic
Position
With
the switch
in
the
AUTOMATIC
position,
the
Sequence
Control
will
operate
automatically
through
all
sequences
with
the
use
of
a
contactor
control
switch
connected
to
the
CONTACTOR
CONTROL
receptacle.
A.
Start Weld
Amperage
Control
(Sequence
B)
The
START
control is
provided
for
selecting
the
start
weld
current
value.
The control is
adjustable
and
can
be
set
for
any
value
from the
minimum
to
the
maximum
of
the
selected
current
range
on
the
welding
power
source.
For
a
normal
start
the
control should
be
set
for
a
value less
than the
WELD
(sequence
C)
setting.
B.
Weld
Amperage
Control
(Sequence
C)
The
WELD
control
is
provided
for
selecting
the
normal weld
current
value.
The
control
is
adjustable
and
can
be
set
for
any
START
WELD
AMPERAGE
CONTROL
PILOT LIGHT
FOR
GAS
AND
WATER
GAS AND
COOLANT
PRE-FLOW
TIME
CONTROL.~~,
B.
Manual
Position
With
the
switch
in the
MANUAL
position,
the
timers
of
sequences
B, C,
and
D
are
removed
from the
circuit.
However,
the
weld
sequence
current value
will
be
controlled
by
the
WELD
amperage
control
on
the
Sequence
Control.
Closing
the contactor
control
switch
will
initiate
sequence
A
)PRE-FLOW).
Upon
completion
of
sequence
A,
the
WELD
sequence
will be initiated
automatically.
The
Sequence
Control
will
continue
to
operate
in
the
WELD
sequence
until
the
contactor
control
switch is
opened.
Opening
this switch
will
extinguish
the
WELD
sequence
and
initiate
sequence
E
(POST-FLOW
gas
and
coolant
time).
SLOPE WELD
1
AMPERAGE CONTROL
GAS AND
COOLANT
POST-FLOW
CONTROL
2
SLOPE
WELD

TIME
CONTROL
WELD
.T!~TIME
CONTROL
VOLTAGE CHANGEOVER
TERMINAL BLOCK FOR
CONTROL TRANSFORMER
Sequence
A:
Sequence
B:
Sequence
C:
PILOT
LIGHT
FOR
WELD
EACH
WELD
SEQUENCE
AMPERAGE
CONTROL
START
WELD
TIME
CONTROL
TERMINAL
BLOCK
FOR
EXTERNAL
SWITCH
OPERATION
AND
EMERGENCY
STOP
SWITCH
CONNECTION
I.
HIGH FREQUENCV
SPARK
GAP
Figure
3-2. Control
Panel
View
OM-540
Page
3

3-5.
MANUAL
CONTROL
OF
SEQUENCE
C
Provisions
are
provided
for
manual
timing
of
sequence
C
to
allow
Continuous
welding
for
any
desired
time.
This
is
accomplished
by
connecting
an
external switch
into
the
Circuit. Refer
to
Section
2-7
for
information
on
connecting
the
external
switch.
The
Sequence
Control
functions
auto
matically
through
sequences
A
and
B,
but
the time
duration
of
sequence
C
is controlled
by
the
external
switch.
Closing
the
external
switch will
extinguish
sequence
C
and
initiate
the
SLOPE
weld time
(sequence
DL
3-6. HIGH-FREQUENCY
CONTROL
(Figure
2-2)
The
high
frequency
is
controlled
through
the
Direct-Air
coupling jumper
links
and the
HIGH-FREQUENCY
switch
labeled
START-OFF-CONTINUOUS.
A. Direct-Air
Coupling
Located
on
each
side
of the
high-frequency
panel
are
three
terminals and
one
jumper
link.
The
positions
of the
links
are
labeled
DIRECT
and
AIR. These
links
provide
facilities
for
connecting
the
high-frequency
transformer for either
direct
or
air
coupling
which
governs
the
amount
of
high-frequency
intensity.
To
increase
the
intensity,
connect
both
links
in
the
SECTION
4
-
SEQUENCE
4-1.
GAS
TUNGSTEN-ARC
WELDING
(GTAW)
For
Gas
Tungsten-Arc
Welding
(GTAW(.
check and
adjust
the
controls
as
follows:
1.
Check
that
shielding
gas
and coolant
connections
are
as
described
in
Sections
2-3
and
2-4.
2.
Check
that
secondary
connections
are as
described
in
Section
2-2.
3.
Determine
the
type
of
welding
current
required
(AC,
DCSP,
or
DCRP(,
and
position
the
Polarity
switch
or
Selector switch
on
the
welding
power
source
accord
ingly.
4.
Place the
Range
switch
on
the
welding
power
source
in
the
desired
current
range.
5.
Rotate
the
AMPERAGE
ADJUSTMENT
control
on
the
welding
power
source
to
the
maximum
position.
6.
Rotate
the
START
weld
amperage
control,
WELD
amperage
control,
and
the
SLOPE
weld
amperage
control
on
the
Sequence
Control
to
the
desired
setting.
7.
Place
the
WELD
switch
in
the
desired
position.
The
AUTOMATIC
position
is
generally
used,
but
the
MANUAL
position
may
be
employed.
8.
On
SCE/SCM-1A
Models,
place
the
START
switch
in
the
desired
position
according
to
the
welding
appli
cation.
9. Place
the
HIGH-FREQUENCY
switch
in
the
START
position
for
dc
welding,
and
in the
CONTINUOUS
position
for
ac
welding.
10.
Adjust
the
shielding
gas
and
coolant
pre-flow
and
post-flow
timers
for
the
desired time
setting.
11.
Select
the
proper
size
tungsten
for the
welding
application
from
Table 4-1.
12.
Connect
a
normally-open
switch
into the
CON
TACTOR
CONTROL
receptacle.
to
welding,
it
is
imperative
that
proper
protective
clothing
(welding
coat
and
gloves)
and
eye
protection
(glasses
and
welding
helmet)
be
put
on.
Failure
to
comply
may
result
in
serious
and
even
permanent
bodily
damage.
position
labeled
DIRECT.
To
decrease
the
intensity,
connect
both links
in
the
position
labeled AIR. This
unit
was
shipped
with
the
links
connected
in
the
DIRECT
position.
B.
Off
Position
With
the switch in the
OFF
position, high
frequency
is1
removed from
the
weld
circuit.
This
position
must
be
used
for
Shielded Metal-Arc
Welding
(SMAW).
C. Start
Position
With the
switch
in
the
START
position,
high
frequency
is
induced
into
the
weld circuit
as
an
aid
in
starting
the
arc.
When
a
welding
arc
is
established,
the
high
frequency
will
automatically
shut
off. This method
is
recommended
for
DC
Gas
Tungsten-Arc
Welding
(GTAW).
D. Continuous
Position
With
the
switch in
the CONTINUOUS
position,
high
fre
quency
is
induced
into the
weld
circuit
during
all three
welding
sequences,
or as
long
as
the
contactor
is
energized.
This
method is recommended for
AC
Gas
Tungsten-Arc
Welding
(GTAW).
OF
OPERATION
14. Close
the
contactor
control
switch
and
commence
welding.
15.
Readjust
the
controls
as
necessary
for
proper
welding
condition.
4-2.
SHIELDED
METAL-ARC WELDING
(SMAW)
For
Shielded Metal-Arc
Welding
(SMAW)
check
and
adjust
the
controls
as
follows:
1. Disconnect
or
shut
off
the
shielding
gas
and
coolant
supplies.
2. Check
that
secondary
connections
are as
described
in
Section
2-2.
3.
Determine
the
type
of
welding
current
required
(AC,
DCSP
or
DCRP),
and
position
the
Polarity
switch
or
Selector
switch
on
the
welding
power
source
accord
ingly.
4. Place
the
Range
switch
on
the
welding
power
source
in
the desired
current
range.
5.
Rotate
the
AMPERAGE
ADJUSTMENT
control
on
the
welding
power
source
to
the
maximum
position.
6.
Rotate
the
WELD
amperage
control
(sequence
C)
on
the
Sequence
Control for
the approximate
percentage
of
weld
current
desired
within
the
range
selected
on
the
welding
power
source.
7. Place
the
WELD
switch
in
the
MANUAL
position.
8.
On
SCE/SCM-1A
Models,
adjust
the
START
weld
amperage
control
to
approximately
the
same
setting
as
the
WELD
amperage
control
setting.
9.
On
SCEISCM-1A
Models,
place
the
START switch
in
the desired
position
according
to
she
welding
application.
10. Place
the
HIGH-FREQUENCY
switch
in
the
OFF
position.
11.
Connect
a
normally-open
switch
into
the
CON
TACTOR
CONTROL
receptacle.
to
welding,
it is
impera
ye
that
proper
protective
clothing
(welding
coat
and
gloves)
and
eye
protection
(glasses
and
welding
helmet)
be
put
on.
Failure
to
comply
may
result
in
serious and
even
permanent
bodily
damage.
I
13.
Place
the
POWER
switch
on
the
welding
power
source
in
the
ON
position.
Page
4

12.
Place
the POWER
switch
on
the
welding
power
source
in
the
ON
position.
13.
Close
the
contactor
control switch
and
commence
welding.
14.
Readjust
the controls
as
necessary
for
proper
weld
condition.
4-3. SHUTTING
DOWN
1.
Break
the
arc.
2.
Allow
the
welding
power
source
to
idle for
3
minutes
with
no
load
applied.
3.
Place
the
POWER
switch
in
the
OFF
position.
4.
Turn
off
the
shielding
gas
supply
if
used.
~ding
is
performed
in
a
confined
area,
failure
to
_______________
turn off the
gas
supply
could result
in
a
buildup
of
gas
fumes, endangering
personnel
reentering
the
welding
area.
_______________
SECTION
5
-
MAINTENANCE
~ng
the
P0
WER
switch
the
OFF
position
d
oes
not
remove
power
from all
of
the
welding power
source
internal
circuitry.
Completely
terminate
all
electrical
power
to
the
welding
power
source
by
employing
machinery
lockout
procedures
before
attempting
any
inspection
or
work
on
the inside
of
the
welding
power
source
or
the
Sequence
Control,
If
the
welding
power
source
is
connected
to
a
disconnect
switch,
padlock
the
switch
in
an
open
position.
If
connected
to
a
fuse
box,
remove
the
fuses
and
padlock
the
cover
in
the
closed
position,
If the
unit is
connected
to
a
circuit
breaker,
or
other
disconnecting
device
without
locking
facilities,
attach
a
red
tag
to
the
device
to
warn
others
that
the
circuit is
being
worked
on.
Widening
of the
spark
gaps
through
normal
operation
may,
if
not
corrected,
increase
the
loading
of
the
high
voltage
capacitors
and thus contribute
to
their
premature
failure.
Cleaning
or
dressing
of the
point
is not
recommended
as
the
material
at
the
points
is
tungsten
and
is
impossible
to
file.
The
entire
points
should be
replaced
when
they
become
extremely pitted
or
burned
to
such
an extent
that little
or
no
tungsten
is left.
To
adjust
spark
gaps
proceed
as
follows:
A.
Loosen
screws
(A) on
both
sides.
B. Place
an
.008
inch
feeler
gauge
in
spark
gap
area
(C).
C.
Apply slight
pressure
against
spark
point
(B)
so
feeler
gauge
is
held
firmly
between
the two
points,
D.
Tighten
screws
(A),
5-1.
HIGH
VOLTAGE CAPACITORS
These
parts
are
rarely
a
source
of trouble.
Any
local
radio
repair
shop
Can
readily
determine
the condition of the
capacitors.
If
one
of
the
high
voltage
capacitors
fail,
operation
may
be
continued
with
one
capacitor
until
a new
one can
be
secured.
To
prevent
excessive
overload
on
the
remaining
single capacitor,
the
spark
gap
point setting
should
be
reduced
to
about
.004
inches.
5-2.
SPARK
GAP
ADJUSTMENT
(Figure
5-1)
The
spark
gaps
can
readily
be
inspected by
opening
the
door
of the
Sequence
Control. The
spark
gaps
are
set at
.008
inches
when
shipped.
It
will
be
necessary
to
periodically
readjust
these
after
extended
operation.
Usually,
inspection
and
adjustment
every
three
to
four months
will suffice.
Readjustment
is
indicated
when intermittent
operation
of the
gaps
is noted.
Usually
this
occurs
when
the
gap
setting
has
increased
to
.012
inches
or
greater.
The
high-frequency output
varies
directly
(up
to
a
certain
point)
with the
spark
gap
spacing.
In
extreme
cases
where
the
greatest
amount
of
high frequency
is
needed,
it
may
be
necessary
to
adjust
the
gap
setting
to
.010
inches
or
greater.
This
increases the
high-frequency
radiation;
therefore,
it
is
suggested
that
the
minimum
gap
setting
(.008
inches)
consistent
with
good
welding
operation,
be used.
Figure
5-1.
Spark Gap Adjustment
TA-020
623
Table
4-1
Guide
For
Selecting
Electrode
For
Gas
Tungsten-Arc
Welding
I
0
PURE TUNGSTEN CURRENT
RANGE
Electrode Dta.
lIn.l
ACHF-Argon
DCSP.Argon
DCSPHelium
.010
Up
to
15
Up
to
15
Up
to
20
.020
10
to
30 15
to
50 20
to
60
.040
20w
70
25
to
70 30 to
90
1/16
50
to
125
50 to 135 6Oto 150
3/32
1/8
100 to
160
-
150
to
210
125
to
225
215
to
360
140
to
250
240
to
400
 
5/32
3/16
190
to
280
250 to
350
350
to
450
450
to
720
390
to
500
500
to
800
1/4
300
to
500 720
to
990
800
to
1100
1% AND 2% THOR ATED
TUNG STEN
.010
Up
to
20
Up
to
25
Up
to
30
.020
15to35 15to50 20to60
.040
20 to 80 25 to
80 30
to
100
1/16
50
to
140 50
to
145
60 to
160
3/32
130
to
250 135
to
235
150
to
260
1/8
225
to
350
225
to
360
250
to
400
5/32
300
to
450
360
to
450
400
to
500
3/16
400
to
650
450
to
720
500
to
800
1/4
500
to
800 720
to
990
800
to
1100
TA-gO
I
190-3
OM-540
Page
5

5-3. BYPASS PANEL
5-4. CONTROL
CIRCUIT
PROTECTION
The
purpose
of
the
bypass panel
is
to
reduce
the
high-fre
quency
feedback
into
the
transformer of
the
welding power
source.
A
defective
capacitor
in
this Circuit
would
reduce
high-frequency
output,
and
might
be
evident
by
loss of oil
from
the
capacitor
case.
If
in doubt
as
to
the condition of
the
capacitors,
have them
checked
at
a
radio
repair
shop.
The resistors
in the
Circuit would show evidence
of
failure
if
they
are
cracked.
Failure
in this
circuit
is
rare,
and
would
be
suspected
only
as a
last
resort.
The
Sequence
Control
is
equipped
with fuses
protecting
the
control
circuit
components.
The
diagram markings
and
quantity
of
fuses
may vary
depending
on
the model.
Normally
the
fuses
can
be
easily
inspected by opening
the
cabinet door
and
examining
the
interior of
the
unit.
Consult
the
circuit
diagram
at
beginning
of
welding
power
source
Owners
Manual
for
specific
information
on
this
unit. The
proper
information
about
specific
fuses
can
be
determined
from
the
Parts
List.
Hazardous
voltages
are
present
on
the
internal Cir
cuitry
of this Unit
as
long
as
power
is
connected.
Disconnect
power
before
attempting any
inspection
or work on
the
inside
of
the
Unit.
Troubleshooting
of
internal
circuitry
should be
performed by
qualified
personnel
only.
The
following
chart
is
designed
to
diagnose
and
provide
remedies
for
some
of
the
troubles that
may
develop
in
this
unit.
It is
assumed
that
proper
installation
has
been
made,
according
to
Section
2
of this
manual,
and that the
unit has
been
functioning
properly
until
this
trouble
developed.
Use
this
chart in
conjunction
with
the circuit
diagram
while
performing
troubleshooting
procedures.
If the
trouble
is
not
remedied
after
performing
these
procedures,
the
nearest
Factory
Authorized
Service Station
thould
be
contacted.
In
all
cases
of
equipment malfunction,
the
manufacturers
recommendations should
be
strictly
followed.
Tt~~i~
SECTION
6
-
TROUBLESHOOTING
I
I
I
TROUBLE PROBABLE
CAUSE
SUGGESTED CHECK
AND/OR
REMEDY
All
sequences
inoperative;
no
output.
Gas
and
coolant
flows
for
a
brief
period
and then
shuts
off
(transformer
Ti
is
energized).
Fuse
F6
open. ~Replace
fuse
F6
(see
Section
5.4).
Remote Hand
Switch
not
tight in
receptacle
Rd.
Ensure
that
Remote Hand
Switch is
secure
in
receptacle
RC1.
All
sequences
inoperative;
no
output.
Gas
and
coolant
does
not
flow (transformer
Ti
is
energized).
Fuse
F7
open.
~Replace
fuse
F7
(see
Section
5-4).
Sequence
Control
entirely
moper-
ative
(transformer
Ti
not
ener
gized).
Fuse
F8
open.
~RepIace
fuse
F8
(see
Section
5-4).
Normal
output;
no
high
frequency.
High-frequency
switch
in
OFF
position.
Place
high-frequency
switch
in
proper
position.
Incorrect
spark
gap.
Check
spark
gap.
Adjust
as
required.
See Section
5-2.
Shorted
high
voltage
capacitor(s).
Replace
capacitor(s).
Normal
output.
Low
high
frequency.
Incorrect
spark
gap.
Check
setting
for
.008
inch. See
Section 5-2.
High-frequency
leaks.
Check all
connections
for
high-frequency
leaks.
Incorrect direct-air
coupling.
Check
that both links
are
connected
for
the
same
coupling.
Erratic
weld
current.
Poor
tungsten.
Check
tungsten
and
replace
if
contaminated.
Incorrect
polarity.
Check
polarity.
Incorrect
welding
cable size
or
loose connections,
Check
for
proper
weld cable
size
(see
Section
2-2).
Tighten
all
welding
cable
connections.
Poor
ground
at
workpiece.
Check
ground
connections.
Contactor
pulls
in.
Incorrect
operating
voltage
of
relay
CR3.
Adjust
slider
on
resistor R2
so
relay
CR3
pulls in
on
open-circuit
voltage.
Weld
current
does
not
shut
off.
Incorrect
operating
voltage
of
relay
CR3.
Adjust
slider
on
resistor
R2
so
relay
CR3
drops
out
when
welding
arc
is
initiated.
Contactor
does
not
pull
in.
Blown
fuses
F6
and/or
F7
in
control
circuitry.
~Replace
fuses
F6
and/or
F7
(see
Section
5-4).
if
it becomes
necessary
to
replace
any
fuse
in
this
unit,
ensure
that
a
fuse of
the
proper
size is
used.
See
beginning
of
welding
power
source
Owners
Manual
for circuit
diagram.
I I~
Page
6