Welding Operation - Lincoln Electric Invertec STT II Operator's Manual

B-4
6. WIRE SIZE SELECT SWITCH: This toggle switch
selects between electrode diameters of .035" (1
mm) and smaller or .045" (1.2 mm) and larger. The
.035" (1 mm) position provides improved perfor-
mance of smaller diameter wires at higher wire feed
speeds.
7. WIRE TYPE SELECT SWITCH: This toggle switch
selects between mild or stainless steel. In the stain-
less position, the pulse width of the Peak Current is
changed from 1 to 2 ms for better performance for
stainless steel welding.
8. THERMAL SHUT-DOWN INDICATOR:
This light will indicate that either the internal
thermostat(s) or the FET over current sen-
sor has actuated. Machine output will return after
the internal components have returned to normal
operating temperature (if the thermostat(s)
"opened") or after about 3-7 seconds (if the FET
over current sensor activated).
9. REMOTE RECEPTACLE: This is a 10 pin MS-
type connector for remote control of Peak Current
and Background Current. Trigger switch connec-
tions are also provided. The presence of the mating connec-
tor is automatically sensed, disabling the front panel Peak
and Background Current controls. Refer to "REMOTE CON-
TROL CONNECTOR" in the ACCESSORIES Section of this
manual for more information.
10. WIRE FEEDER RECEPTACLE: This is 14
pin MS-type connector for the wire feeder
connection. 115 and 42 VAC along with
the trigger switch connections are provided. (Only
42 VAC is available on European models). There
are no provisions for voltage control of the power
source by the wire feeder.
Accessories section of this manual for wire feeder
connection instructions.
11. ARC SENSE RECEPTACLE: This is a four pin
MS-type connector for WORK and ELECTRODE
sense leads. The STT requires a WORK sense
and ELECTRODE sense lead for proper operation.
The ELECTRODE sense lead is bolted together
with power source electrode lead at the wire feeder
gun block. The WORK sense lead is furnished with
an "alligator" type clip for connection to the work
piece. Refer to the LN 742 or STT-10 wire feeder
connection instructions in the Accessories section
of this manual for proper connection of these leads.
12. 42V AUXILIARY POWER CIRCUIT BREAKER:
The 42 VAC supply is protected from exces-
sive current draws with a 6 amp circuit break-
er. When the breaker "trips" its button will
extend. Depressing this button will reset the breaker.
OPERATION
13. 115V AUXILIARY POWER CIRCUIT BREAKER
(Not on European Models): The 115 VAC
supply is protected from excessive current
draws with a 6 amp circuit breaker. When
the breaker "trips" its button will extend.
Depressing this button will reset the breaker.
14. WORK TERMINAL: This twist-mate con-
nection is the negative output terminal for
connecting a work cable and clamp to the
workpiece.
15. ELECTRODE TERMINAL: This twist-
mate connection is the positive output ter-
minal for connecting an electrode cable to
the wire feeder conductor block. Refer to
the Accessories Section for wire feeder connection
instructions.

WELDING OPERATION

Familiarize yourself with the controls on the Invertec
STT II before beginning to weld.
Familiarize yourself with the operating manual for the
wire feeder and the wire feeder controls before begin-
ning to weld.
Set the Wire Size and Wire Type selection switches
per the appropriate wire. Refer to "Operational
Features and Controls" in this section for the function
of these switches.
Refer to the
INVERTEC STT II
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