IEEE C57.12.01-2020

This standard describes electrical and mechanical requirements of single and polyphase ventilated, nonventilated, and sealed dry-type distribution and power transformers or autotransformers, with a voltage of 601V or higher in the highest voltage winding. This standard applies to all dry-type transformers, including those with solid-cast and/or resin encapsulated windings except as follows: a) Instrument transformers b) Step and induction-voltage regulators c) Arc-furnace transformers d) Rectifier transformers e) Specialty and general-purpose transformers f) Mine transformers g) Testing transformers h) Welding transformers