scope:

This part of IEC 61558 deals with the safety of constant voltage transformers for general applications and power supply units for constant voltage for general applications. Constant voltage transformers incorporating electronic circuits are also covered by this standard. NOTE 1 Safety includes electrical, thermal and mechanical aspects. Unless otherwise specified, from here onward, the term transformer covers constant voltage transformers for general applications and power supply units for constant voltage for general applications. This part is applicable to stationary or portable, single-phase or polyphase, air-cooled (natural or forced), independent or associated dry-type: - constant voltage auto-transformers; - constant voltage separating transformers; - constant voltage isolating transformers; - constant voltage safety isolating transformers. The windings may be encapsulated or non-encapsulated. This standard is applicable to transformers and power supply (linear) with internal operating frequencies not exceeding 500 Hz.