IEEE C57.12.57

Description / Abstract: This standard is intended to set forth characteristics relating to performance, limited electrical and mechanical interchangeability, and safety of the equipment described herein, and to assist in the proper selection of such equipment.

This standard describes certain electrical and mechanical characteristics and takes into consideration certain safety features of three-phase, 60-Hz, two-winding, ventilated dry-type network transformers generally used for step-down purposes, high-voltage 34 500 volts and below; low-voltage 216Y/125 and 480Y/277 volts with self-cooled ratings 2500 kVA and smaller. Forced-air ratings are listed in Part II.

This standard does not apply to other types of transformers, such as specialty, sealed dry-type, pad-mounted dry-type, liquid-immersed, instrument, regulating, furnace, mine, and rectifier transformers. Transformers with high voltage 600 volts or less are excluded.

As used in this standard, the word ?shall? indicates mandatory requirements, and the words ?should? and ?may? refer to matters that are recommended and permissive, respectively, but not mandatory.

NOTE - The Foreword of this standard describes the circumstances under which the document may be used on a mandatory basis.

Part I of this standard describes electrical and mechanical requirements. Part II describes other requirements or alternatives that may be specified.