Lincoln Electric SVM129-B Recommended Equipment, Operating Controls, Welding Capability

B-3 B-3

OPERATION

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GENERAL DESCRIPTION

The Invertec STT II 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 conventional short circuiting GMAW. The process is optimized for short- circuiting GMAW welding.

•High temperature Class H insulation.

•Protection circuits and ample safety margins prevent damage to the solid state components from transient voltages and high currents.

•Preset welding current capability.

•STT II offers improvements over the previous model. Approximately 40% increase in deposition rate capa- bility, and a significant increase in travel speed.

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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 has the following controls as stan- dard: 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, light- weight 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.

WELDING CAPABILITY

The Invertec STT II 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 reasonable 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).

INVERTEC STT