400 A All-in-One Welding Power for MIG, TIG, Stick, Gouging & More
The Miller XMT 400 is a heavy-duty multiprocess welding power source engineered for fabrication shops, industrial repair, and demanding environments. It delivers 400 A at 60 % duty, supports multiple weld modes (MIG, TIG, Stick, Flux-cored, Gouging), and includes advanced features like Auto-Line™ for voltage flexibility, ArcConnect™ communications, and Wind Tunnel™ cooling to protect internal electronics from contaminants.
With its versatility and rugged design, the XMT 400 is built to be the centerpiece of a flexible welding setup—ideal for shops that need to perform many processes with one machine.
The XMT 400 is a popular power source for shops that primarily perform heavy MIG welds, but also need the ability to burn stick electrodes and occasionally need to perform light gouging. While it does have the ability to perform DC TIG welds with lift TIG, we don't often see companies purchase this power source with the intent of using it for TIG.
Features:
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Auto-Line™: Automatically adapts to 208–600 V, single- or three-phase power with no manual voltage linking.
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ArcConnect™: Next-gen communication between power source and feeder, enabling point-of-use control and smarter arc behavior.
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Wide Process Support: MIG (GMAW), Flux-cored, Stick (SMAW), TIG (GTAW), Gouging (CAC-A), and advanced modes like Versa-Pulse, HD MIG, RMD
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Wind Tunnel™ Cooling: Internal airflow design protects electronics by pulling air through and away from sensitive areas.
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Fan-On-Demand™: Cooling fans only run when needed, reducing noise, energy use, and dust ingress.
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Auto Remote Sense™ (ARS): Detects if a remote control is plugged in, preventing switching confusion.
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EZ-Set & Memory Modes: Simplified parameter setup and storage of welding jobs for repeatability.
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Backwards Compatibility: Some models offer both ArcConnect and Miller’s standard 14-pin control ports for compatibility with older feeders.
| Parameter |
Value |
| Amperage Range |
15 A – 425 A |
| Processes Supported |
MIG, Flux-cored, Stick, TIG, Gouging |
| Open Circuit Voltage |
91 VDC |
| Input Voltage |
208–600 V (single- or three-phase) |
| Warranty |
3 years (True Blue) |
| Additional Modes & Technologies |
Versa-Pulse, HD MIG, RMD, Accu-Pulse, etc. |
Why Choose the XMT 400?
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One machine handles almost any welding process you’ll need
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Voltage flexibility means it adapts to different job sites without rewiring
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Protects electronics in tough shop environments with advanced cooling
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Smart control features reduce setup time and learning curve
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Upgrade options and modular architecture give it long service life
CLICK HERE FOR SPECIFICATION SHEET
