KEMPPI X3S POWER SOURCE SYN 420 G

Kemppi X3S Power Source Syn 420 G — Industrial Synergic MIG/MAG Power Source (420 A)

The Kemppi X3S Power Source Syn 420 G is an industrial synergic MIG/MAG power source delivering 420 A at 60% duty cycle and 350 A continuous from a 400 V 3-phase supply. Includes 45 factory-installed welding programs, 1-MIG synergic, Manual MIG, MMA, and gouging. Generator-compatible. Part of the X3 FastMig system.

What Is the Kemppi X3S Power Source Syn 420 G?

The Kemppi X3S Power Source Syn 420 G is the highest-output synergic model in the X3 FastMig family, delivering 420 A at a 60% duty cycle and 350 A at 100% continuous duty from a standard 3-phase 380–415 V power supply. It is the single-voltage, fixed-installation power source in the X3S range — built for heavy industrial fabrication environments where maximum synergic MIG/MAG output on a standard 400 V supply is the priority.

The G designation confirms generator compatibility, with a recommended minimum generator output of 25 kVA — extending the machine's reach to construction sites, maintenance shutdowns, and remote operations where 3-phase mains infrastructure is unavailable.

The X3S Power Source Syn 420 G is a power source only — it pairs with the X3 HD200 or X3 HD300 wire feeder to form a complete X3 FastMig MIG/MAG welding system. The control panel, DuraTorque 4x4 wire drive, and program interface are housed in the wire feeder, making the power source the dedicated energy platform of the system.

Supporting four welding processes — 1-MIG (synergic), Manual MIG/MAG, MMA (stick), and carbon arc gouging — and arriving with 45 factory-installed welding programs covering the most common industrial filler materials, the X3S 420 G is ready for production welding from the moment it is commissioned.

Designed and manufactured in Finland. Compliant with IEC 60974-1 and -10.

Key Features of the Kemppi X3S Power Source Syn 420 G

420 A at 60% Duty Cycle — Maximum Synergic Output in the X3S Range

The X3S Power Source Syn 420 G delivers 420 A MIG output at a 60% duty cycle — the highest output in the X3S synergic series. At 100% continuous duty, it sustains 350 A, making it genuinely capable of extended production welding runs without thermal interruption. For MMA welding, maximum output is 400 A at 60% duty cycle and 330 A continuous. This output headroom supports the most demanding heavy fabrication, structural steel, and large-section weld applications encountered in industrial MIG/MAG welding.

45 Factory-Installed Welding Programs — Production-Ready From Day One

The X3S 420 G ships with 45 factory-installed 1-MIG welding programs that are immediately usable straight out of the box — no additional program purchases, no software configuration, and no commissioning delay. Programs cover the full range of common industrial filler materials and diameters:

• Fe — mild steel solid wire, 0.8–1.6 mm
• Ss — stainless steel solid wire, 0.8–1.6 mm
• AlSi5 — aluminium alloy wire, 0.8–1.6 mm
• AlMg5 — aluminium alloy wire, 0.8–1.6 mm
• Fe Metal — metal-cored wire, 0.9–2.0 mm
• Fe Rutil — rutile flux-cored wire, 0.9–1.6 mm
• FC-CrNiMo — flux-cored CrNiMo wire, 1.2–1.6 mm
• CuSi3 — silicon bronze wire, 0.8–1.2 mm

With 45 programs across these materials, the vast majority of professional heavy fabrication welding applications are covered before the first arc is struck.

1-MIG Synergic Welding — Automated Parameter Control

In 1-MIG (synergic) mode, the X3S 420 G automatically coordinates welding voltage and wire feed speed from a single arc length control input. The operator selects the filler material, wire diameter, and shielding gas from the pre-installed program library — and the machine maintains the correct parameter relationship automatically throughout the weld. This eliminates the need to manually balance two independent variables, reducing setup errors, improving arc consistency, and delivering repeatable weld quality across different operators and shifts. For industrial environments where consistent quality on high-volume or long-seam welding is essential, 1-MIG synergic is a direct productivity multiplier.

Icon-Based User Interface — Fast Setup, No Language Barriers

The X3 FastMig system's non-language icon-based control interface — located on the paired X3 wire feeder control panel — provides immediate, intuitive process, program, and parameter selection without requiring language-specific menu navigation. Any operator can set up and begin welding quickly, regardless of experience level or native language. In multi-national workforces, apprentice-heavy environments, and high-turnover industrial operations, this interface design directly reduces setup errors and training requirements.

Dual Operating Mode — AUTO and MANUAL

The X3S 420 G system supports two operating modes via the wire feeder panel:

• AUTO mode — synergic 1-MIG, where the machine manages voltage and wire feed speed from a single arc length parameter, using the pre-installed program library
• MANUAL mode — full independent control over voltage and wire feed speed for experienced welders who prefer to set parameters directly

The ability to switch seamlessly between AUTO and MANUAL modes makes the X3S 420 G equally suitable for operators who prefer guided synergic control and those who prefer full manual input.

Welding Cable Calibration Without Sensing Cable

The X3S 420 G supports welding cable calibration without a separate voltage sensing cable — measuring circuit resistance internally to ensure the displayed arc voltage accurately matches actual voltage at the arc. This is a significant practical advantage in industrial environments where interconnection cable lengths change regularly between jobs or sites, and where accurate arc voltage is critical to maintaining weld quality and meeting WPS requirements.

Generator Compatible — Industrial MIG/MAG Anywhere

The G designation confirms the X3S 420 G is rated for generator operation. With a recommended minimum generator power of 25 kVA, it delivers full 420 A synergic MIG/MAG output from a site generator — making it practical for construction sites, major maintenance shutdowns, remote infrastructure projects, and any environment where 3-phase mains is not permanently available.

Marathon Pack Compatible

When paired with the X3 HD300 wire feeder, the X3S 420 G system supports marathon pack (bulk drum) wire configurations, enabling uninterrupted high-volume welding production without frequent spool changeovers. This is a material efficiency and productivity gain on high-throughput production lines, long-seam fabrication, and any application where large wire volumes are consumed in a single shift.

Safe Crane Lift from Wire Feeder Handle

When configured with the X3 HD300 wire feeder, the complete wire feeder assembly — including welding torch, wire spool, and full cable set — can be safely lifted and suspended by crane from the feeder handle. Water hoses and cable connectors are positioned outside the feeder casing for fast torch package swapping and service access. This crane-lift capability is essential for shipyard, heavy structural, and elevated work applications.

Rotating Mounting Plate

The X3 HD300 wire feeder attaches to the X3 power source via a rotating mounting plate, allowing the feeder to be independently positioned and turned relative to the power source — improving cable routing flexibility and ergonomic positioning across different welding cell configurations.

CAN Bus Communication — System Integration Ready

The X3S 420 G uses CAN bus wired communication between the power source and wire feeder, providing robust, high-integrity data transfer throughout the X3 FastMig system and supporting integration with optional remote controls and automated welding system configurations.

Optional Remote Controls

The X3S 420 G system supports the optional HR53 wireless hand remote (with display) and GRe50 on-torch remote, enabling welding current and program adjustment from the torch position without returning to the wire feeder. This is a practical productivity tool for large fabrication bays, long torch cable setups, and positional welding applications.

High Efficiency — 89%

The X3S 420 G achieves 89% power efficiency at rated maximum current — among the highest in its output class. Combined with an idle state power consumption of just 15 W, this efficiency rating directly reduces electrical operating costs in high-volume production environments where machines run for extended shifts.

Who Is the Kemppi X3S Power Source Syn 420 G For?

The X3S Power Source Syn 420 G is designed for:

• Heavy fabrication and structural steel workshops requiring maximum synergic MIG/MAG output on a fixed 400 V 3-phase supply, where pulse MIG is not required
• Shipyards and offshore fabricators running 1-MIG synergic on steel, stainless steel, and aluminium with marathon pack capability and crane-lift wire feeder configurations
• Production welding lines where 420 A output at 60% duty cycle supports high-deposition, long-seam, or thick-section welding without thermal interruption
• Mining, civil, and infrastructure contractors needing maximum synergic output from a site generator for maintenance, shutdown, and construction welding
• Operations standardising on a single high-output MIG platform across steel, stainless steel, aluminium, cored wire, and silicon bronze filler materials — all covered by 45 pre-installed programs
• Multi-operator workshops where the icon-based interface and 1-MIG AUTO mode reduce setup errors and skill barriers across different operators and shifts

Kemppi X3S Power Source Syn 420 G — Technical Specifications

X3S 420 G vs X3P 450 G vs X3P 400 GM — Choosing the Right X3 FastMig Power Source

Frequently Asked Questions — Kemppi X3S Power Source Syn 420 G

What does X3S 420 G mean? X3S identifies this as the Synergic model in the X3 FastMig family — supporting 1-MIG synergic and Manual MIG/MAG welding, MMA, and gouging, but not Pulse MIG. 420 is the maximum welding output in amps at 60% duty cycle. G indicates generator compatibility, with a recommended minimum generator output of 25 kVA.

Is the X3S 420 G a complete welding system? No. The X3S 420 G is a power source only — it requires a paired X3 HD200 or X3 HD300 wire feeder to form a complete X3 FastMig welding system. The wire feeder contains the control panel, DuraTorque 4x4 wire drive, and welding program interface. Power source and wire feeder are purchased and configured separately.

Does the X3S 420 G support pulse MIG welding? No. The X3S 420 G supports 1-MIG synergic welding, Manual MIG/MAG, MMA, and carbon arc gouging. Pulse MIG/MAG requires an X3P model — the X3P Power Source Pulse 450 G (single voltage, higher output) or the X3P Power Source Pulse 400 GM (multi-voltage, generator-compatible).

What is the duty cycle of the X3S 420 G? The X3S 420 G delivers 420 A MIG at a 60% duty cycle and 350 A MIG at 100% continuous duty cycle. For MMA welding, it delivers 400 A at 60% duty cycle and 330 A at 100% continuous duty.

What is the difference between the X3S 420 G and the X3S 400 GM? The X3S 420 G delivers a higher maximum output of 420 A at 60% duty cycle, but accepts only standard 3-phase 380–415 V input and includes 45 pre-installed programs. The X3S 400 GM delivers 400 A at 60% duty cycle (380–460 V) or 400 A at 40% duty cycle (220–230 V) with multi-voltage flexibility, and includes 42 programs. The 420 G is preferred where maximum synergic output on a fixed standard supply is the priority; the 400 GM is preferred where multi-voltage or international operation is required.

What is the difference between the X3S 420 G and the X3P 450 G? The X3P 450 G delivers higher maximum output (450 A vs 420 A at 60% DC) and adds Pulse MIG/MAG capability — increasing its program count from 45 to 71, as the additional programs cover both synergic and pulse processes. Both machines share the same physical dimensions (698 × 251 × 361 mm) and weight (35 kg). The X3S 420 G is the preferred choice where synergic MIG is sufficient and pulse capability is not required, offering a more cost-effective entry into high-output X3 FastMig performance.

What generator is needed to run the X3S 420 G? Kemppi recommends a minimum generator output of 25 kVA to power the X3S 420 G at full welding capacity.

What filler wire types does the X3S 420 G support? The X3S 420 G supports Fe (mild steel solid), Ss (stainless steel), AlSi5 and AlMg5 (aluminium), CuSi3 (silicon bronze), Fe Metal (metal-cored), Fe Rutil (rutile flux-cored), and FC-CrNiMo (flux-cored CrNiMo) wires from 0.8 mm to 2.0 mm diameter — all covered by the 45 factory-installed welding programs.

Can the X3S 420 G be used with a marathon pack? Yes. When paired with the X3 HD300 wire feeder, the X3S 420 G supports marathon pack (bulk drum) wire configurations for continuous high-volume welding without frequent spool changeovers.

What remote controls are available for the X3S 420 G? The X3S 420 G system supports the optional HR53 wireless hand remote (with display) and GRe50 on-torch remote control for welding current and program adjustment from the torch position — eliminating the need to return to the wire feeder during welding.