本标准旨在阐述与所述设备的性能、有限的电气和机械互换性以及安全性相关的特性，并帮助正确选择此类设备。 本标准描述了某些电气和机械特性，并考虑了60 Hz、双绕组、三相、通风干式变压器的某些安全特性，自冷额定值为501 kVA及以上，通常用于降压目的。第二部分列出了特定尺寸的强制风冷额定值。 具体的额定值组合范围为750/1000至7500/10000 kVA（含），高压2400至34 500伏（含），低压208Y/120至4160伏（含）。 本标准不适用于其他类型的变压器，如专用、通风干燥变压器- 500 kVA及以下型号、密封干式、垫装干式、液浸式、仪表、调节、熔炉、矿山和整流变压器。不包括高压600伏或以下的变压器。 当本标准强制使用时，单词a？莎拉？表示强制性要求，以及a？应该吗？还有一个？玛雅？分别指建议和允许但非强制性的事项。

This standard is intended to set forth characteristics relating to performance, limited electrical and mechanical interchangeability, and safety of the equipment described, 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 60-Hz, two-winding, three-phase, ventilated dry-type transformers with self-cooled ratings 501 kVA and larger, generally used for step-down purposes. Forced-air-cooled ratings for certain sizes are listed in Part II. Specific rating combinations are described in the range from 750/1000 to 7500/10 000 kVA inclusive, with highvoltage 2400 to 34 500 volts inclusive and low-voltage 208Y/120 to 4160 volts inclusive. This standard does not apply to other types of transformers such as specialty, ventilated dry-type 500 kVA and smaller, 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. When this standard is used on a mandatory basis, the word "shall" indicates mandatory requirements, and the words "should" and "may" refer to matters that are recommended and permissive, respectively, but not mandatory.