EWM Thyristor MIG 500 with a separate Thyristor 4x4 feeder is a heavy industrial MIG/MAG source on a transformer with a thyristor rectifier and factory liquid cooling. The documentation gives 500 A at a 45% duty cycle, 450 A at 60% and 350 A at a continuous 100% load. Supply is 3 x 400 V at 50/60 Hz, and the coolant tank holds 7 l.
What this machine is for
This is a set for industrial welding shops, makers of heavy steel structures and maintenance departments. You set the current from 45 A to 500 A, the voltage steplessly from 16 V to 39 V, and in work without breaks the source holds 350 A, so you lay long welds on thick sections, heavy walled pipes, frames and tanks without waiting for the machine to cool down. The thyristor rectifier stack gives stepless adjustment, so you are not shut inside the steps of transformer taps and you match the arc power exactly to the material thickness and the chosen gas.
The Thyristor 4x4 feeder has a four roll drive and takes wires from 0.6 mm to 2.4 mm in diameter at a speed from 1 m/min to 20 m/min, and the factory rolls are usually for wire from 1.0 mm to 1.2 mm. Such a drive also carries cored, rutile and basic wires without slip, the ones you work with on thick parts. After fitting U type rolls and a PTFE liner and picking the soft choke characteristic, the machine will also pull aluminium and other non ferrous metals under argon.
The machine has no synergic programs and no pulse. The arc voltage, the wire speed and the choke dynamics are set by the process engineer or the welder, by hand, for the given process. For serial production that is an advantage, because parameters once agreed do not change when a program is switched, and tracing a fault comes down to checking the power components, not the software. A design with a massive transformer, a choke, a measuring shunt and a thyristor stack takes mains disturbance and the current loads typical for large halls. In practice this means a machine that works two shifts at 350 A and does not report an error after every voltage swing in the switchboard, and the parts for it are simple: rolls, contact tips, nozzles, contactors and thyristors, without control modules tied to the machine number.
Features and equipment
- Stepless voltage adjustment by a thyristor stack: you set the arc voltage steplessly from 16 V to 39 V from the feeder panel, without the jumps known from tap switches.
- Two dynamics steps on the choke, as two current sockets on the front of the source: the soft output calms the arc under argon and on aluminium and limits spatter, the hard output gives a dynamic arc with deeper penetration under CO2 on heavy steel.
- Creep Start, that is an adjustable wire start speed in a range from 0% to 100% of the working speed: the wire comes up to the material more slowly, the start is calmer and spatters less, and after the strike the controller goes over to the main speed.
- Burn-back, adjustment of the wire burn back time from 0 ms to 250 ms after the feed stops: the end of the wire does not stick to the freezing pool and does not burn back into the contact tip, so the next strike comes at once.
- Integrated liquid cooler with a 7 l tank, with a pressure and flow sensor: at a pressure drop or a loss of circulation the system cuts the welding current itself and protects the torch from burning out.
- Thyristor 4x4 feeder on a turning base: a four roll drive, a EURO torch connector and red and blue coolant quick couplings, and the turning base widens the reach at the station.
- Control panel placed on the feeder: the voltage, the wire speed, Creep Start, Burn-back and the 2T or 4T switch are at the part, not at the source.
- Working modes 2T and 4T: 2T for short repair welds, 4T on long production runs, where holding the trigger tires the hand.
- Wire inching button on the feeder: you thread the filler through the torch without switching on the current and without gas flow.
- Digital current and voltage displays on the front panel of the source: you read the working values during the work.
- Source on a wheeled chassis: in spite of a weight of about 205 kg you roll it across a level hall floor without a forklift.
- Open circuit voltage from 17 V to 45 V: the arc strikes surely across the whole setting band, also on material that is tarnished or covered with scale.
- Insulation class H and protection class IP23: the windings take a high working temperature, and the housing takes the dust and damp typical for a welding shop.
Technical data
| Brand | EWM |
|---|---|
| Source model | Thyristor MIG 500 |
| Feeder model | EWM Thyristor 4x4, separate |
| Type | MIG/MAG on a transformer with a thyristor rectifier, manual control |
| Supply voltage | 3 x 400 V, 50/60 Hz |
| Mains fuse | 3 x 25 A time delay |
| Welding current range | from 45 A to 500 A |
| Welding voltage range | from 16 V to 39 V |
| Current at a 45% duty cycle | 500 A |
| Current at a 60% duty cycle | 450 A |
| Current at a continuous 100% load | 350 A |
| Open circuit voltage | from 17 V to 45 V |
| Source cooling | fan |
| Torch cooling | liquid, 7 l tank |
| Feed mechanism | 4 rolls, 4x4 layout |
| Wire feed speed | from 1 m/min to 20 m/min |
| Wire diameters supported | from 0.6 mm to 2.4 mm, factory rolls from 1.0 mm to 1.2 mm |
| Torch connector | EURO |
| Insulation class and protection class | H, IP23 |
| Source dimensions | about 1110 x 550 x 890 mm |
| Feeder dimensions | about 650 x 440 x 265 mm |
| Source weight in the water cooled version | about 205 kg |
| Feeder weight | about 18.5 kg |
| Working temperature | from 10°C to 40°C |
| Processes | MIG/MAG, solid and cored wires |
What you get
- EWM Thyristor MIG 500 source on a chassis, with a liquid cooling circuit and a 7 l tank
- separate EWM Thyristor 4x4 four roll feeder on a turning base, with a EURO connector
What to watch out for
The set needs a 3 x 400 V mains at 50/60 Hz with a 3 x 25 A time delay fuse, and the working temperature given in the documentation runs from 10°C to 40°C. The source measures about 1110 x 550 x 890 mm and weighs about 205 kg in the water cooled version, so it is a stationary unit: for unloading you need a forklift or a pallet truck, and the feeder of about 18.5 kg you carry separately. Before continuous work check the level and the cleanliness of the fluid in the 7 l tank and the tightness of the quick couplings, because the flow sensor will cut the welding current if the circuit stops.
The factory rolls are usually for wire from 1.0 mm to 1.2 mm, so for thinner wires or for 2.4 mm choose the right set of rolls and guides. The machine has no synergy and no pulse, you set the parameters by hand, which at a first station means finding the working point by trial on a test bead. The housing has protection class IP23 and insulation class H, it takes the dust and damp of a hall, but not washing with a jet.
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.
