USA Standard General Requirements for Distribution, Power and Regulating Transformers, and Shunt Reactors

This standard was revised and greatly expanded in 1948, 1949, and 1956. The 1956 edition was comprised of a revision and editorial consolidation of the preceding standards on distribution, power , and regulating transformers, namely American Standard Requirements for Distribution, Power , and Regulating Transformers, and Reactors Other Than Current-Limiting Reactors, C57.12-1949, American Standard Test Code for Distribution , Power, and Regulating Transformers , C57.22-1948, and American Standard Requirements for Transformers-67,000 Volts and Below; 501 Through 10,000 kva, 3 Phase ; 501 Through 5,000 kva, 1 Phase, C57.12a-1954. In addition, in order to eliminate cross-references wherever possible, the consolidation contained excerpts from other standards of the C57 family