EWM WEGA 401, used MIG/MAG welder

The EWM Wega 401 is a transformer MIG/MAG power source on copper windings, run from a 3 x 400 V supply. You set the current from 30 to 400 A, at a 45% duty cycle the machine holds 400 A, and in continuous work 270 A. The set is modular: a separate four roll feeder, a liquid cooling module on a trolley and stepped voltage adjustment in 24 ranges.

What this machine is for

This is a source for heavy industry, in which toughness counts, not a set of functions. A copper transformer takes thermal overloads and voltage spikes in a dirty plant mains, and the power reserve steadies the current curve, so the strike is soft and the penetration easier to lead by hand. Where steel dust destroys inverter electronics, such a construction keeps working. The open circuit voltage is about 45 V, and you pick the welding voltage with a rotary tap switch out of 24 ranges.

Above 28 V, with gases rich in argon, the arc moves from the short circuit phase to the spray phase and the drops detach without contact with the pool. This mode gives strong penetration in a thick, bevelled edge and little spatter, but it forces work in down hand positions, because the volume of the molten metal rules out welding overhead. The maker pointed this model to thick walled pipelines in transmission stations, to assembly of steelworks and mining plants, to structures of cranes, hoists and semi trailers, to rebuilding of excavator armour with cored wires, to prefabrication of viaduct spans and to production of sea containers. The common denominator of these jobs is long, even fusion runs on thick material, where the machine simply has to last shift after shift.

A large part of the practical value here comes from separating the source and the feeder. The feeder joins the source with an interconnection cable, so the welder walks into a tank or into a tight structure with the feeder alone, instead of dragging the whole machine. The drive has four toothed rolls on bearings, which hold the wire also with a sharply bent torch and with spools of cored wire, where slipping shows in the weld at once. With hard steel wire 1.2 mm the four roll layout spreads the pressure more evenly than two rolls, so the teeth do not rub off the copper coating and do not dirty the inside of a long current package. The panel of the feeder is analogue, with thick switches and knobs you handle in gloves, without displays, which in damp and dust are often the first part to change.

Features and equipment

• Copper transformer block: resistance to thermal overloads and to voltage swings in dirty plant mains, without sensitive control boards.
• Current range from 30 to 400 A with a 45% duty cycle at 400 A and 100% at 270 A: reserve for the spray arc and a real current for long work.
• Stepped voltage adjustment in 24 ranges: the position you pick binds the voltage mechanically, without changes of its own as the core heats up.
• Welding choke with taps: you change the inductance of the circuit for the gas and the alloy you use, so you limit sparking with CO2 and form the face on thin carbon sheet more easily.
• Separate four roll feeder on an interconnection cable: four toothed rolls on bearings hold the wire with a bent torch and with cored wires, and you carry the feeder itself into places where the source will not fit.
• Stepless adjustment of the feed speed up to 24 m/min: you set the rate of wire feed steplessly, with thick knobs you handle in gloves.
• Liquid cooling module with a tank up to 7 litres: the pump holds a pressure up to 3.5 bar at a flow of 5 litres per minute and protects the contact tips in work at 400 A.
• Wire threading test without current: the feeder motor turns without switching the current on, so you thread the wire through the liner without the risk of a short circuit.
• Gas test without current: the solenoid valve opens the flow without striking the arc, which lets you set the flow meter and find a kinked hose before production starts.
• 2T and 4T modes: two stroke for hundreds of small tacks, four stroke for long continuous welds without holding the trigger.
• Spot welding cycle: the timer puts the arc out after a set time, so the spots have the same depth and look, and thin galvanised sheet does not burn through on an overlap.
• Stitch welding cycle: the current switches on and goes out at even intervals, and the cooling pauses limit rippling of thin tubes and stainless railings.

Technical data

What to watch out for

The supply is 3 x 400 V, the protection class is IP23, and the set weighs about 250 kg, so plan the transport and moving it with a fork lift or a crane. At 400 A the duty cycle is 45%, longer work you plan at 270 A. The stepped adjustment does not let you correct the voltage while the arc burns or pick it to within tenths of a volt, and in jobs that need such precision that is a real limit.

The cooling system needs the fluid level watched and the filters cleaned from time to time, and the torch has to be made for water. The interconnection cable between the source and the feeder has to be protected against being run over and its continuity checked, because that is the most common place of failure in such sets. The area of the rolls is cleaned from time to time, and the rolls and the liner are matched to the diameter and the type of wire. The machine has no job memory, you note the settings for repeatable parts outside the machine, best on a work sheet at the bay. A change of the choke taps needs the cables moved by hand when you change the gas or the alloy, which with frequent rotation of production is sometimes a nuisance, but in return you cannot do it by accident from a menu. The spray arc forces work in down hand positions, for overhead welds you need another technique or another process.

This unit is sold

This machine has already gone to a customer. Similar units are listed below, and if you want the same model, leave your contact details in the form and we will let you know when the next one arrives.