Autotransformer 120/240V-100A

The Victron Autotransformer 120/240V 100A is designed to optimise power management in split phase electrical systems, helping trade professionals, installers and system integrators unlock the full capacity of their available supply. Common applications such as generators, grid feeds and inverter based systems can suffer reduced output when 120V loads fall unevenly across both legs. As appliances switch on and off, current imbalance forms, limiting practical power to levels well below theoretical capability.

This autotransformer solves the issue by creating a new neutral connection. Instead of unused capacity being wasted on the lighter phase, the transformer absorbs the difference through its windings. This allows the system to maintain full output, improving efficiency and reliability when a mix of 120V and 240V loads are present. For a 30A 120/240V supply the improvement is notable, helping achieve the expected 7.2kVA capacity even when high current appliances are unevenly distributed.

A further advantage is its ability to simplify system design. Rather than stacking two smaller 120V inverters to achieve a split phase supply, a single 240V inverter paired with this autotransformer can provide balanced power distribution while also offering more flexibility when load unpredictability is expected. It reduces unnecessary hardware costs and wiring complexity while improving total draw on one leg when the other remains lightly loaded.

Safety has also been considered. The unit features a grounding relay that ensures correct neutral bonding in inverter mode, essential for proper GFCI function in a split phase environment. This relay is controlled automatically by compatible Victron inverter chargers. In addition, thermal protection disconnects the transformer from supply when overheating is detected, requiring a manual reset once temperatures return to safe levels.

With versatile performance and dependable protection features, this autotransformer is well suited for marine, off grid, industrial, backup power and mobile applications where load patterns vary and reliable output is required.

Autotransformer 120/240V-100A – Manual

Autotransformer 120/240V-100A – Data Sheet