The Lincoln Electric Square Wave TIG 255 is a transformer TIG power source for alternating and direct current, with an MMA mode and liquid cooling. You set the current from 5 to 315 A, and the square wave of the alternating current shortens the time of the passage through zero and holds the arc steady on aluminium. The set holds a TIG torch 4 m.
What this machine is for
Alternating current with a square wave is what handles aluminium. Fast switching of the polarity cuts the time in which the current passes through zero to a minimum, so the arc does not go out, the pool does not swim and the oxide layer comes off evenly. You set the wave balance yourself, that is you decide how much energy goes to cleaning the oxides and how much to the depth of penetration. Direct current takes stainless and mild steel.
A reserve up to 315 A lets you weld thick aluminium castings, oil sumps and frame structures, and the lower limit of 5 A handles thin parts. The documentation aims this model at metalwork shops, at firms rebuilding machine parts and at workshops working on aluminium and stainless steel. The panel has clear scales and graphic hints on the settings for the material thickness, so a new person avoids typical mistakes faster, such as excess electrode wear or a lack of penetration.
A transformer build with copper windings of a large cross section gives a large thermal inertia and resistance to dust, so the machine does not drift off the parameters in work over many hours. Liquid cooling lets you weld with the torch at a current above 200 A without overheating the grip and the wear parts.
Features and equipment
- Square Wave technology: the square wave of the alternating current shortens the time the current spends around zero, so the arc is steady and the oxide cleaning effect is clear without extra ionising circuits.
- Wave balance control: you set the proportion between the cleaning of the oxides and the depth of penetration yourself, and that counts on castings and on dirty material.
- Current range from 5 to 315 A: one machine for thin parts and for thick aluminium items, from fine metalwork to rebuilding a casting.
- Transformer with copper windings of a large cross section: a large thermal inertia, low sensitivity to metal dust and a smooth arc characteristic, because copper of a large cross section limits the energy losses. The machine does not overheat as fast as light inverter builds and holds the welding current in work over many hours, at the cost of the weight of the unit.
- Integrated liquid cooling: the torch stays cool in work above 200 A, and the wear parts last longer.
- MMA mode: after you change the cables over you weld with a covered electrode, so the same power source covers a correction or assembly work in a place where the gas shield will not hold, for example outside the hall.
- Panel with hints: grouped functions lead you through the choice of the balance and of the start and end current, and graphic scales suggest the settings for the material thickness. When you change the part you reset the machine in moments, without leafing through the manual, and you work the solid switches in welding gloves.
Technical data
| Brand | Lincoln Electric |
|---|---|
| Model | Square Wave TIG 255 |
| Type | transformer TIG AC/DC power source with an MMA mode |
| Welding current range | from 5 to 315 A |
| Maximum welding current | 315 A |
| Current type | AC/DC |
| Welding methods | TIG AC/DC, MMA |
| AC wave shaping | Square Wave, adjustable balance |
| Cooling | liquid, forced system |
| TIG torch | 4 m |
| Earth cable | 3 m |
| Supply cable | 3 m |
| Welding current given on the card | up to 400 A |
What you get
- TIG torch 4 m
- earth cable 3 m
- supply cable 3 m
What to watch out for
The card gives a welding current up to 400 A and the source description a range from 5 to 315 A, so confirm the value on the rating plate. Neither the card nor the source description gives the supply voltage, so before you buy settle what socket you need, and check it on the plate together with the draw. A transformer power source has its weight and pulls more from the mains than an inverter of similar rating, so plan the place where it stands and the transport.
Liquid cooling is a separate circuit, in which you check the fluid level and the flow through the hoses in the torch before the first weld. For aluminium you need clean argon and an electrode picked for alternating current, and an extreme wave balance wears its tip faster.
How we sell used machines
This unit was checked in our service workshop in Krotoszyn with measurements to PN-EN 60974-4 and a load test. The price includes the first year of the basic service package: an inspection with cleaning of the machine and a validation measurement. Further years can be added. We ship across the European Union, collection in person by appointment.
