BLOCK's STO series is designed according to the European and international standards EN/IEC 61558-2-2, the EN/IEC 61558-2-4 but without the UL 5085 as the relevant safety standard for North American UL certification.
As a result, the STO series is as much as 25% to 30% less expensive and excellent for applications within Europe, Asia and Australia where UL certification is unnecessary.
Control transformers provide safe galvanic isolation from the primary to the secondary side. The STO series is designed with an input voltage of 230 or 400 Vac and an output of 24 or 230 Vac in several capacities from 63 to 1600VA. This makes them ideal for control circuits and mechanical engineering. Thanks to the unique IMPEX vacuum impregnation process, transformer is excellently protected against external influences. This construction guarantees reliable operation and makes them suitable for use in harsh, dusty and humid production environments where safety and stability are crucial.
In addition to the STO, Block has other series that do have UL certifications.
