The Miller Dynasty 300 DX is an inverter TIG AC/DC power source with pulse and an MMA mode. You set the current steplessly from 5 to 300 A, at a 15% duty cycle the machine gives 300 A, and in continuous work 180 A. We sell this unit in its original setup: with a Miller cooler, a trolley, a TIG torch 4 m and an earth cable 3 m.
What this machine is for
The DX version gives full freedom in shaping the alternating current. Control of the AC balance and frequency lets you separate the cleaning of the oxides from the penetration, so on aluminium you take the aluminium oxide layer off and keep a narrow and deep fusion zone. The pulse steadies the arc and limits the heat affected zone, and that counts on thin walled structures from titanium and from stainless steel, where overheating shows at once in the colour and the geometry of the part.
The lower limit of 5 A handles very small parts, and the top of 300 A is enough for thicker joints, so one unit covers a wide range of work. The documentation names aluminium, magnesium, stainless steel, copper and titanium. The maker aimed this model at aviation, at motorsport, at prototype building and at the chemical industry, that is where control over the arc at low currents and a repeatable joint count.
Features and equipment
- Stepless current control from 5 to 300 A: from small parts to thicker joints without changing the machine.
- TIG AC/DC, TIG pulse and MMA processes: with alternating current you weld aluminium and magnesium, with direct current steels and titanium, and with a covered electrode you make quick repairs.
- AC balance control: you set the proportion between the cleaning phase and the fusing phase for the state of the material surface.
- AC frequency control: you narrow or widen the arc and decide where the heat goes.
- Welding current pulse: the arc is steadier and the heat affected zone narrower on thin walled parts from titanium and stainless steel.
- Original Miller cooler matched to the power source: the cooling system works with the machine electronics, with no random components.
- Miller welding trolley: the power source, the cooler and the gas cylinder travel together, you move the station as a whole.
Technical data
| Brand | Miller |
|---|---|
| Type | inverter TIG AC/DC power source |
| Welding current range | from 5 to 300 A, stepless control |
| Duty cycle at 40 degrees C | 300 A at 15%, 180 A at 100% |
| Supply | 400 V, three phase |
| Process types | TIG AC/DC, TIG pulse, MMA |
| Torch cooling | liquid, original Miller cooler |
What you get
- Miller Dynasty 300 DX AC/DC power source
- original Miller cooler
- Miller welding trolley
- TIG torch of 4 m length
- original earth cable of 3 m length
What to watch out for
The supply is 400 V three phase, so you need a power connection in the workshop. The duty cycle at 40 degrees C is 300 A at 15% and 180 A at 100%, that is at the full current one and a half minutes of welding fall on ten minutes, and long welds you plan around 180 A. The cooling is run by liquid, so count in a check of the fluid, the pump and the hoses, because a liquid cooled torch with a dry circuit you damage in seconds.
The set with the power source, the cooler and the trolley takes up space at the station and calls for planned transport. For aluminium prepare a separate set of tungsten electrodes and count on a higher use of argon than on steel.
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.
