This standard is for sealed dry-type transformers, 501 kVA and larger, with high-voltage 601 to 34500 volts inclusive and low-voltage 208Y/120 to 4160 volts inclusive. This standard is intended to set forth characteristics relating to performance, limited electrical and mechanical interchangeability, and to assist in the proper selection of such equipment.This standard does not apply to other types of transformers, such as specialty, ventilated dry-type, padmounted dry-type, liquid immersed, instrument, regulating, furnace, mine, and rectifier operations. This standard describes certain electrical and mechanical characteristics of 60-Hz, two-winding, threephase, sealed dry-type transformers rated 501 kVA and larger, generally used for step down purposes. This standard will accomplish this by presenting basic electrical and mechanical requirements and describing other requirements or alternatives that may be specified for some applications. New IEEE Standard - Inactive-Reserved. Characteristics relating to performance, limited electrical and mechanical interchangeability, and guidance to assist in the proper selection of sealed dry-type transformers are provided in this standard. Specific rating combinations are described in the range from 750 to 5000 kVA inclusive, with high-voltage 2400 to 34500 Volts inclusive and low-voltage 208Y/120 to 4160 Volts inclusive. Sealed dry-type power transformers filled with only dry air or nitrogen, at the time of filling, are considered. Other gases are not considered in this standard. This standard does not apply to other types of transformers, such as specialty, ventilated dry-type, pad-mounted dry-type, liquid immersed, instrument, regulating, furnace, mine, and rectifier transformers.