Lincoln Electric INVERTEC IM904 - Manual (Page 14)

B-2 OPERATION B-2
INVERTEC STT II (CE)
GENERAL DESCRIPTION
The INVERTEC STT II (CE) is a 225-ampere inverter
based arc welding power source specifically designed
for the STT welding process. It is neither a constant
current (CC) nor a constant voltage (CV) machine. It
is a power source that delivers current of a desired
wave form and characteristics that are superior to con-
ventional short circuiting GMAW. The process is opti-
mized for short-circuiting GMAW welding.
RECOMMENDED EQUIPMENT
The LN-742 or STT-10 wire feeder is recommended
for use with the STT II. The LN-7 GMA, LN-9 GMA,
NA-5, and NA-5R can all be used with the STT II.
However, these units can only be used to feed wire
since these feeders have no provision for control of
the STT output.
OPERATING CONTROLS
The INVERTEC STT II (CE) has the following controls
as standard: On/Off switch, Peak Current adjustment,
Background Current adjustment, Hot Start adjustment,
Tailout, and 2 toggle switches; one for wire size selec-
tion and one for wire type selection.
DESIGN FEATURES AND ADVANTAGES
• State of the art inverter technology yields high
power efficiency, excellent welding performance,
lightweight and compact design.
• Twist-Mate ™ output terminals.
• Digital meters for procedure settings are standard.
• Automatic Inductance or Pinch Control.
• Solid state circuitry for extra long component life.
• Current feedback ensures that original procedure
settings all remain constant.
• Arc Sense lead assembly (Electrode and Work),
connects through a 4-pin case front connector.
• Peak Current and Background Current may be
remotely controlled.
• Thermostat and FET over current protector prevent
overheating from overloads, high ambient tempera-
tures, or loss of air flow.
• High temperature Class H insulation.
• Protection circuits and ample safety margins prevent
damage to the solid state components from tran-
sient voltages and high currents.
• Preset welding current capability.
• STT II offers improvements over the previous model.
Approximately 40% increase in deposition rate
capability, and a significant increase in travel speed.
WELDING CAPABILITY
The INVERTEC STT II (CE) is rated at 225 amps, 29
volts, at 60% duty cycle on a ten minute basis. It is
capable of higher duty cycles at lower output currents.
If the duty cycle(s) are exceeded, a thermal protector
will shut off the output until the machine cools to a rea-
sonable operating temperature.
LIMITATIONS
• May not be suitable for use in an environment with
High Frequency present. (
“ See Machine Grounding
and High Frequency Protection ” in the Installation
section of this manual)
• Suitable for indoor use only (IEC IP21S).