SR EN IEC 61558-2-2:2025

This part of IEC 61558 deals with the safety of control transformers and power supply units incorporating control transformers. Transformers incorporating electronic circuits are also covered by this document. NOTE 1 Safety includes electrical, thermal and mechanical aspects. Unless otherwise specified, from here onward, the term transformer covers control transformers and power supply units incorporating control transformers. For power supply units (linear) this document is applicable. For switch mode power supply units IEC 61558-2-16 is applicable together with this document. Where two requirements are in conflict, the most severe take precedence. This document does not apply to transformers covered by IEC 60076-11. This document is applicable to stationary or portable, single-phase or polyphase, air-cooled (natural or forced) independent or associated dry- type transformers. The windings can be encapsulated or non-encapsulated. The rated supply voltage does not exceed 1 000 V AC and the rated supply frequency and the internal operating frequencies do not exceed 500 Hz. The rated t