scope:

This part of IEC 61558 deals with the safety of bell and chime transformers and power supply units incorporating bell and chime 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 bell and chime transformers and power supply units incorporating bell and chime 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 is applicable to stationary, single-phase, air-cooled (natural or forced) independent or associated dry-type transformers. The windings can be encapsulated or non encapsulated.