Miller Big Blue 700X Duo Pro

Multi-Arc Welding is Now Simpler & More Versatile.

Independent Auxiliary Generator

  • One 5500 Watt peak/ 4000 Watt continuous 240V single phase generator, regardless of weld output.
  • Second generator provides 27,000 Watts peak/20,000 Watts continuous 3 phase power (380 - 415V).

700A Single Arc Capability

  • Two outputs can be paralleled, providing a single 700A output.
  • Suitable for Arc Air Gouging or Sub Arc Process.

Enclosed Robust Case Design

Protects internal components from impact and allows air flow to cool and prolong the life of the engine, while reducing sound levels.


Provides positive Stick electrode starts making it easy to start all types of electrodes, plus it works well for bead tie-ins.

Quick and Easy Maintenance

Single-side access to oil level check, oil fill, oil filter, fuel filter and air cleaner.

Remote Tool-Less Oil Drain

Allows oil to be drained without getting under the engine and reduces the chance of oil spillage.

Heavy-Duty Low Speed Industrial Diesel Engine

Designed, built and proven to operate over 10,000 hours before the first basic overhaul.

Weatherproof Lexan® Nameplate

Resists cracking and fading, and is color-coded for ease of operation.

Meter Maintenance Displays

  • Fuel gauge.
  • Hour meter function.
  • Oil change interval.
  • High coolant temperature and low oil pressure shutdowns.
  • Low fuel shutdown — engine shuts down before system runs out of fuel, making restarts easy.

Standard Features Include:

Stick, MIG, Flux Cored, Lift-Arc™ TIG and digital preset weld meters, output contactor control and automatic idle.

Auxiliary Power*

  • 1 x 380 V 32 Amp Sockets
  • 2 X 240 V 15 Amp Sockets
  • RCD.

*Generator auxiliary power is 60Hz, and intended for operating equipment associated with welding, such as angle grinders, drills  and floodlights. Some Australian 50Hz equipment incorporating induction motors, such as pumps, fans, air compressors, refrigeration or air-conditioners, may not operate correctly and could be damaged. Refer to appliance supplier or manufacturer to confirm suitability.

Technical Data

Welding Mode:  CC/CV/DC

Amp/Volt Range: 40 - 800 A

Rated Output: 500 A at 40V, 100% Duty cycle, 700A at 28V 60% Duty cycle

Generator Power: Peak 5 500 Watts, Continuous: 4 000 Watts, 3-PH 27kwPeak-20kwcontinuous 1-PH 19kg Peak - 12kw Continuous

Dimensions (mm): H 1270  W: 724 D: 1654

Weight (without Fuel): 784 kg

Appliactions and Processes


Structural Steel

Process Piping

Mining Maintenance

Heavy Construction

Cross Country Pipelines




Flux Cored


Air Carbon Arc