Victron Autotransformer: Split-Phase Setup
Updated 6 September 2026 · By SolarNevs Research Desk, Dealer surveys + verified sources · 1 source · Method ↗
Key Takeaways
- The Autotransformer 50 A 100 A provides high-efficiency split-phase 120/240V balancing and voltage stepping.
- Universal voltage flexibility: Input/output Voltage 120 / 240 V.
- Built-in breaker protection: Input Circuit Breaker 50A, Two Pole 100A, Two Pole.
- Line frequency support: Frequency 50/60Hz.
- Full 240V power transfer: Maximum 240 V Feed Through Current 50A 100 A.
- Sustained neutral balancing: Neutral Current, Continuous 45A @ 40°C/100°F.
- Short-term peak imbalance headroom: Neutral Current, 30 min 55A @ 40°C/100°F.
- Low-noise magnetic engineering: Transformer Type Toroidal.
- Corrosion-resistant chassis: Enclosure Aluminum.
- Heavy-gauge terminal lugs: Electrical Terminals Screw Terminals 35 mm² / AWG 2.
- Drip-proof casing rating: Protection Category IP21.
- Physical mass: Weight 12,5 kg 13,5 kg.
- Cabinet dimensions: Dimensions (h x w x d) 460 x 214 x 110 mm.
Split-Phase 120/240V Balancing Architecture
In North American off-grid installations, 120V household loads are often distributed unevenly across two 120V legs. Connecting an Autotransformer to a 240V European inverter allows the transformer to carry the unbalanced neutral current, keeping leg voltages perfectly symmetrical.
The Victron Autotransformer provides split-phase 120/240V load balancing and step-up/down transformation (Continuous Neutral: 45A @ 40°C | Feed-Through: 50A / 100A, 50/60Hz):
- AC Input / Output: 120 / 240 V Config, 50A / 100A 240V Feed, 35 mm² / AWG 2 Term, 50 / 60 Hz Line.
- Toroidal Balancing: Toroidal Core, 45A Contin. Neut., 55A (30 min Peak), Step-Up / Step-Dn.
- Protection: 2-Pole Breaker, 50A or 100A, IP21 Alum., Ground Relay.
Installation Rules & Electrical Connections
- Supply Connections: Land heavy AC power cables into the Electrical Terminals Screw Terminals 35 mm² / AWG 2 across Input/output Voltage 120 / 240 V and Frequency 50/60Hz.
- Protection Switchgear: Engage the integrated Input Circuit Breaker 50A, Two Pole 100A, Two Pole protecting the Maximum 240 V Feed Through Current 50A 100 A circuit.
- Neutral Current Management: Size neutral conductors to manage **Neutral Current, Continuous 45A @ 40°C/100°F and **Neutral Current, 30 min 55A @ 40°C/100°F.
Toroidal Core Design & Neutral Balancing
The Autotransformer delivers high efficiency and low idle loss:
- Toroidal Magnetic Core: Built around a Transformer Type Toroidal winding for silent operation and low standby power dissipation.
- Aluminum Enclosure: Encased inside an Enclosure Aluminum rated Protection Category IP21, with Weight 12,5 kg 13,5 kg and Dimensions (h x w x d) 460 x 214 x 110 mm.
- Multi-Model Lineup: Available across Autotransformer 50 A 100 A continuous configurations.
Technical Specifications & Sizing Summary
Parameter | Engineering Rating | Design Significance |
|---|---|---|
Model Hierarchy Lineup | Autotransformer 50 A 100 A | Scalable balancing capacities for marine and off-grid systems |
Operating AC Voltage | Input/output Voltage 120 / 240 V | Configurable step-up, step-down, or split-phase balancing |
Primary Circuit Breaker | Input Circuit Breaker 50A, Two Pole 100A, Two Pole | Integrated thermal-magnetic two-pole overcurrent protection |
Operating Frequency | Frequency 50/60Hz | Universal compatibility with 50Hz and 60Hz AC systems |
Max 240V Feed-Through | Maximum 240 V Feed Through Current 50A 100 A | Handles total continuous pass-through power |
Continuous Neutral Current | Neutral Current, Continuous 45A @ 40°C/100°F | Sustained neutral imbalance handling in hot climates |
Peak Neutral Current (30m) | Neutral Current, 30 min 55A @ 40°C/100°F | Handles large temporary single-leg motor starts |
Magnetic Core Technology | Transformer Type Toroidal | Low acoustic hum and high transformation efficiency |
Cabinet Construction | Enclosure Aluminum | Lightweight corrosion-resistant aluminum housing |
Power Screw Terminals | Electrical Terminals Screw Terminals 35 mm² / AWG 2 | Large terminals accommodate heavy copper conductors |
Ingress Category | Protection Category IP21 | Drip-proof indoor equipment room rating |
Net Weight | Weight 12,5 kg 13,5 kg | Heavy-duty commercial transformer build |
Cabinet Dimensions | Dimensions (h x w x d) 460 x 214 x 110 mm | Compact wall-mounted chassis footprint |
References
- Victron Energy: Autotransformer Manual — accessed 31 August 2026
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