General Description

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OPERATION

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The Square Wave TIG 355 is a constant current, single range square wave AC/DC TIG (GTAW) arc welding power source with built-in high frequency stabilization. It also has stick (SMAW) capability. The Square Wave TIG 355 gives the operator full control of the welding current plus the ability to preset weld and start cur- rents. Preflow and postflow timers are included for shielding gas and cooling water control. Altogether the many features of the machine allow part or all of a weld cycle to be preset or "programmed," which sim- plifies the TIG welding process.

The Square Wave TIG 355 includes advanced features such as Auto-Balance™ 2-Step/4-Step Arc Start Switch Operation, start controls, crater controls, spot timer, and status LEDs. Preflow and postflow timers allow control of shielding gas and cooling water.

RECOMMENDED PROCESSES

The Square Wave TIG 355 is recommended for TIG (GTAW) and stick (SMAW) welding processes within its output capability of 2 to 400 amps on both AC and DC polarity. It is compatible with all Magnum TIG acces- sories as well as many industry standard TIG torches, hoses, and water coolers. (See the Accessories sec- tion of this manual.)

OPERATIONAL FEATURES AND CONTROLS

The following operational controls are standard on the Square Wave TIG 355: Local/Remote current control switch, Stick/TIG mode selection switch, TIG 2- Step/TIG 4-Step mode selection switch, High Frequency Continuous/Start/Off switch, Peak Current control, Volts/Amps switch for the digital ammeter reading, AC Wave Balance control, Afterflow timer for shielding gas and water flow, Arc Force current control for stick welding, Preflow timer for shielding gas and water flow, Spot Time Controls, Start current/time controls, Pulse controls (pulses per second, back- ground % peak current, pulse % on), and Crater Fill controls (fade-out, % peak current).

The following additional features are also standard: Digital ammeter selectable for either volts or amps; Status Indicator LEDs for gas and water, high frequen- cy, arc established, start, peak, background, crater fill.

DESIGN FEATURES AND ADVANTAGES

•Designed to NEMA EW-1 and International IEC-974 Standards.

•Single output range of 2-400 amps covers the majority of TIG welding applications.

•Solid State Output Contactor: no noise, no parts to wear.

•Digital Ammeter and Voltmeter for precise readings from 2-400 amps welding.

•Welding current limit can be preset from 2-400 amps and is displayed on the ammeter when not welding.

•Auto Balance™ circuitry automatically provides the proper amount of cleaning and penetration when AC TIG welding. Manual AC wave balance adjust- ment is also possible.

•2-Step/4-Step Arc Start switch capability.

•Spot control for 2-Step Arc Start switch mode.

•TIG Pulser with On/Off selection, and Pulses Per Second adjustment. Background current and duty cycle are automatically adjusted according to the peak welding current.

•Crater Fill control for current fade-out at the end of a weld.

•Adjustable preflow time from 0 to 10 seconds. Preflow time is eliminated if welding restarts during gas afterflow of previous weld. This avoids unnec- essary delays when making repeated welds.

•Adjustable afterflow time control.

•Locate/Remote current selection.

•Stick/TIG selection.

•Arc Force control of added current when electrode shorts to the work in stick mode.

•Continuous/Start/Off High Frequency selection.

•DC+/AC/DC- Polarity switch.

•Power Factor Correction for lower input currents and smaller input wire sizes.

•Remote Receptacle for Amptrol™ or Arc Start switch.

•Low Voltage Arc Start switch circuit (24 VAC) for maximum operator safety.

•Gas and optional water valves: Inlet and outlet fit- tings conform to Compressed Gas Association (CGA) standards.

•Built-In High Frequency Generator.

SQUARE WAVE TIG 355

Lincoln Electric SVM118-A service manual General Description, Recommended Processes

Models: SVM118-A

OPERATION