Lincoln Electric SVM141-A service manual General Description, Recommended Processes and Equipment

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OPERATION

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GENERAL DESCRIPTION

The Square Wave TIG 275 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. A TIG Pulser Kit, Power Factor Capacitor Kit, and a Water Solenoid Kit are available as field installed options.

The Square Wave TIG 275 includes advanced features such as Digital Voltage and Current Meters, Auto Balance™, 2-Step/4-Step operation, adjustable Down slope Time control and Fan as Needed. It also features Twist Mate connections for the electrode and work leads. In addition, fixed preflow and variable post flow timers are included to control the shielding gas, as well as the water flow when using the optional water sole- noid.

RECOMMENDED PROCESSES AND EQUIPMENT

The Square Wave TIG 275 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, as well as many industry standard items, such as TIG torches, hoses, and water coolers.

DESIGN FEATURES AND

ADVANTAGES

•Meets NEMA CLASS II (40) and IP21S environmen- tal certification. (Will be CSA NRTL/C certified in the future.) Domestic and Canadian Models Only.

•Meets IEC-974-1 and IP21S environmental certifica- tion. (Will be CE certified in the future.) European Model Only.

•Built in Digital Ammeter and Voltmeter for precise process control. This includes a persistence feature which captures and continues to display the peak welding current and it’s corresponding voltage for five seconds after the weld is completed.

•AC Wave Balance control knob provides flexibility to the customer. Set it to the Auto Balance position and the circuitry automatically provides the proper amount of cleaning and penetration for normal AC TIG weld- ing. For special applications simply dial in the amount of cleaning and penetration needed.

•Fan As Needed (FAN) circuit turns ‘ON’ the fan only when cooling is needed. FAN minimizes the amount of dust, dirt, and other foreign material drawn into the

machine. A build up of these materials can cause excessive operating temperatures and nuisance shut downs.

•2-STEP/4-STEP TIG/STICK mode control switch. 4- STEP mode requires the use of an optional Arc Start Switch. This welding mode reduces fatigue by elimi- nating the need to manually control the weld current during the weld.

•Down Slope Time control is active in 4-STEP TIG mode. It controls the amount of time (approximately 1 to 10 seconds) it takes the weld current to ramp down from the Preset level to 25% ±10% of that level.

•Post Flow Time control is active in the 2 and 4-STEP TIG modes. It controls the amount of time (approxi- mately 5 to 50 seconds) the shielding gas flows after the weld is completed.

•Robotic Interface connection on the PC board can be connected to the machines Remote Receptacle for automated welding procedures. This interface allows remote control of the trigger and output current of the machine as well as providing a signal when the weld

is established. (For details contact the Lincoln Automation Center)

•Built in High Frequency Generator automatically per- forms in the correct mode. If the machine is in STICK mode, the HF stays ‘OFF’. IF the machine is in DC TIG mode, the HF comes ‘ON’ and stays on until the arc is established. IF the machine is in AC TIG mode, the HF comes ‘ON’ and stays on continuously to sta- bilize the arc.

•Automatic Local/Remote current selection. The machine automatically senses if an Amptrol, Arc Start Switch or TIG Pulser is plugged in and transfers cur- rent control from local to remote.

•Built in preflow time of 0.5 seconds. Preflow time is eliminated if welding restarts during the pervious weld’s post flow. This avoids unnecessary delays when making repeated welds.

•Simple dial and switch design provides the customer with flexible control of the welding process without unnecessary complication. Controls which are not needed in the weld mode selected are automatically locked out.

•Twist Mate connectors are provided for the electrode and work connections. This style connector makes the gas and current connections for the TIG torch at the same time. (Adaptor plugs are provided)

•DC+/AC/DC- Polarity Switch allows the welder to change polarity without reconnecting leads.

SQUARE WAVE TIG 275