Three-phase reversible

The three-phase reversible autotransformer is a transformer consisting of a single winding per phase, the secondary winding being part of the primary winding. Autotransformers are used to precisely adjust the value of the nominal voltage. One of the characteristics of this range is a significant increase in efficiency but also in short-circuit current. Thanks to the reversibility option, autotransformers can be used both to raise or to lower voltage.