Autotransformers are used if galvanic isolation from the supplying mains can be dispensed with. The input and output windings are electrically connected. A distinction is made here between power output and constructional performance, whereby the constructional performance is always less than power output. The smaller the difference between input and output voltage, the smaller the construction work.

Type power = 1 – (undervoltage/overvoltage) * rated power

<a href="https://bre-trafo.de/produkte/dreiphasen-transformatoren/info-einsatz-von-spartransformatoren-in-dreiecksnetzen/"Please note our instructions for the use of three-phase autotransformers!