ESAB LAX 320 is a transformer MIG/MAG power source with a flat voltage and current characteristic, with a welding current up to 320 A and a range from 40 A to 320 A. The supply is 400 V, three phases, the cooling gas, the weight about 110 kg. You set the voltage with two switches, forty steps of adjustment in all.
What this machine is for
This is a source for structural steel welded with solid and flux cored wire under gas shielding, with wires from 1.0 mm to 1.2 mm in continuous work. It goes to metalwork shops, repair plants and to farming, that is where simple handling and work in dust and damp count. You will weld aluminium with it after changing the rolls to a U profile, after fitting a teflon liner in the torch and with argon, and the spray arc is then stable.
The power stage rests on a massive transformer with copper windings and on a separate rectifier block. Such a build is little sensitive to jumps of mains voltage and takes overloads, because copper has a large thermal inertia and a separate rectifier block gives heat away more easily in continuous work. The transformer core limits losses and gives a linear rise of flux, so the metal transfer in the short arc is even, and the arc stays soft and predictable also on low steps, on thin sheet.
Three phase rectification in a full wave bridge strongly limits the ripple of the output voltage. The welding current comes close in its characteristic to direct current, so the metal transfer is smooth and the arc ignites easily also on an oxidised surface. Diodes with a high load capacity on massive aluminium heat sinks take work in a 100% duty cycle without overheating the system, and less spatter means less use of abrasives and shorter cleaning of the structure.
A solid trolley and handles mean that despite the weight you move the machine around the production hall. The station is simple to work and the training of a welder short, because all the settings are on switches and knobs, without a menu.
The advantage of a transformer source over an inverter in workshop conditions is its resistance to dirt, metal filings among them, and the simplicity of repairs. There is no sensitive controller here that drops out of work after sucking in dust from a grinder, and the diagnosis comes down to measurements on the power components. In a dirty and dusty setting that is the difference between a machine that stands and one that works.
The biggest problem of simple stepped sources is the lack of an intermediate setting. The welder then works either too cold, which ends in a lack of fusion, or too hot, which gives burn through. Forty steps of adjustment solve that at the level of the transformer itself, because between two neighbouring settings the difference of voltage is small enough for you to hit exactly the parameters from the welding procedure. On structures put through non destructive testing that is a condition of accepting the part.
The second problem is an unsteady wire feed. Uneven feeding ends in porosity and breaks in the arc, most often through the wire slipping in the rolls. A 4 roll drive guides the wire surely whatever the bend of the torch, and a spread pressure protects the wire from being flattened. With flux cored wires, which are easy to crush, that translates directly into whether the station stands or works.
Features and equipment
- Voltage adjustment over 40 steps, two range switches. The close stepping lets you hit the technological window and avoid an arc that is too cold or too hot, that is a lack of fusion or burn through. Every step matches a set number of transformer turns, so the parameters are repeatable over the whole working range, which matters on structures tested by RT and UT methods.
- Two step inductance adjustment, an output choke with two sockets. The choke slows the rise of the short circuit current, so the metal droplet passes into the pool gently. A higher inductance suits mild steels under CO2 shielding and limits spatter by as much as 30%, a lower one suits Ar/CO2 mixes, where a fast transfer and deep penetration at a higher welding speed count.
- A flat voltage and current characteristic. A stable short arc and predictable behaviour of the pool when the welder changes the arc length by hand. The copper windings have a large thermal inertia, so short overloads do not destroy the insulation and the machine forgives mistakes in use.
- A 4 roll feeder with a synchronous drive. The pressure spreads over a larger area of the wire, so the wire does not deform plastically and does not lose its copper coating. That counts with long torches from 4 m to 5 m and with flux cored wires, which are easy to crush.
- Adjustment of the roll pressure. You set the resistance so that the feed speed is steady and the arc energy does not jump.
- A wire feed range from 1.9 m/min to 20 m/min. It handles both thin sheet at a low speed and fast filling of thick joints.
- Adjustment of the wire burn back time, that is the burn-back function. The wire does not stick to the pool or to the contact tip once welding ends.
- A modular build with a separate rectifier block. Heat leaves more easily, and access to the components makes service easier.
Technical data
| Brand | ESAB |
|---|---|
| Source type | transformer |
| Process | MIG/MAG, manual welding |
| Welding current at a 35% duty cycle | 320 A |
| Welding current at a 100% duty cycle | 190 A |
| Welding current range | from 40 A to 320 A |
| Supply voltage | 400 V, three phases |
| Number of voltage adjustment steps | 40 steps, two switches |
| Wire feed range | from 1.9 m/min to 20 m/min |
| Wire diameters in continuous work | from 1.0 mm to 1.2 mm |
| Wire feeder | 4 roll |
| Cooling | gas |
| Machine weight | about 110 kg |
What you get
- used ESAB LAX 320 power source
- MIG torch 3 m
- earth cable 3 m
- supply cable
What to watch out for
The supply is 400 V, three phases. The duty cycle data differ in the source: the technical table gives 320 A at a 35% duty cycle and 190 A at a 100% duty cycle, while the short product description gives 320 A at a 30% duty cycle and 195 A at a 100% duty cycle. Confirm these values before you buy if you plan continuous work close to the upper limit. The torch is gas cooled, so for the full 320 A you need a torch of the ESAB PSF 305 class or a stronger one, and the torch from the set is 3 m.
The machine weighs about 110 kg, so for transport prepare a trolley or two people, and a fixed place in the hall. For aluminium you need rolls with a U profile, a teflon liner and argon, which the card does not list. There is no pulse or synergic programs here, the welder picks the parameters, and it is worth writing down the settings for repeatable joints at the station.
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.
