General Description

OPERATION

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The Square Wave TIG 255 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. It is available from the factory in one model only; there are no factory installed options, only variations in input voltage and frequency.

The Square Wave TIG 255 includes advanced features such as Auto-Balance™, 2-Step/4-Step Arc Start Switch operation and a TIG pulser. In addition, fixed preflow and variable afterflow timers are included for shielding gas and cooling water control.

RECOMMENDED PROCESSES AND EQUIPMENT

The Square Wave TIG 255 is recommended for the TIG (GTAW) and stick (SMAW) welding processes within its output capacity of 5 to 315 amps, on both AC and DC polarity. It is compatible with all Magnum TIG accessories (see Accessory section in this manu- al), as well as many industry standard items, such as TIG torches, hoses, and water coolers.

OPERATIONAL FEATURES AND CONTROLS

The Square Wave TIG 255 has the following controls as standard: TIG 2-Step/TlG 4-Step/Stick mode selec- tion, Local/Remote current control selection, Continuous/Start Only/Off high frequency selection, Auto/Manual AC wave balance selection with the manual wave balance adjustment, TIG pulser On/Off selection with frequency adjustment, afterflow adjust- ment, and DC+/DC-/AC polarity selection.

DESIGN FEATURES AND

ADVANTAGES

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

•Single output range of 5-315 amps covers the majority of all TIG welding applications.

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

•Digital Ammeter and Voltmeter for precise readings from 5 to 315 amps welding.

•Welding current limit can be preset from 5 to 315 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.

•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.

•Fixed preflow time of 0.5 seconds. Preflow time is eliminated if welding restarts during gas afterflow of previous weld. This avoids unnecessary delays when making repeated welds.

•Adjustable afterflow time control.

•Local/Remote current selection.

•Stick/TlG selection.

•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 V AC) for maximum operator safety.

•Gas and optional Water Valves: Inlet & outlet fittings conform to Compressed Gas Association (CGA) standards.

•Built-in High Frequency Generator.

•115 Volt Receptacle with 10 amp Circuit Breaker.

•220 Volt European (Schuko) type receptacle with 2 amp circuit breaker for water coolers (50/60Hz machines only).

•Excellent arc starting and stability up through 315 amps.

•High resistance to AC arc rectification.

•No tungsten spitting within current range of electrode.

•Compact size, requires only a 19 in x 30 in (485 mm x 760 mm) footprint.

Lincoln Electric SVM100-A service manual General Description, Design Features Advantages

OPERATION