Isolation transformers

Isolation transformers and autotransformers solve two distinct problems associated with alternating current: galvanically isolating two circuits and matching voltages between 115 V and 230 V systems.

What is an isolation transformer used for?

To electrically isolate the installation from the power supply. In boating, this is the solution to the problem of the galvanic corrosion in a harbour: when the boat is connected to the jetty’s earth terminal, the hull becomes electrically connected to those of neighbouring boats and the return currents corrode the anodes.

The transformer cuts off this path: the vessel receives power without sharing a ground reference. It also provides protection against indirect contact in mobile installations.

What is an autotransformer and when do I need one?

An autotransformer steps the voltage up or down without insulation, using a single winding. It is used to operate between systems of 120 V and 240 V, typically on US-built vessels arriving at European ports, or to create a neutral in split-phase systems.

It is not a substitute for an isolating transformer: it steps the voltage up or down, but does not isolate the earth. If you’re looking to prevent galvanic corrosion, you’ll need an isolating transformer.

All models are from Victron Energy, from 2,000 W to 7,000 W. Not sure which one you need? Our technical equipment advises you.