Control transformers (STU)

AEE produces control transformers, also referred to as STU-trafo, ranging from 40VA to 1600VA. The fully custom-made control transformers can be manufactured in single pieces, small runs but also in series, completely according to your specifications. Installation in a cabinet or panel integration is also possible.


A control transformer is a transformer with separate windings that supplies power for an auxiliary power chain. To power the auxiliary power chain, a control transformer is often connected between two phases of a three-phase network. The transformer allows a differing voltage in the auxiliary power chain for electronic components. The design of these transformers is in accordance with EN 61558-2-2. Our control transformers are also available with UL certification (see UL transformers for the specifications)