When is sound level an issue in the design?

Sound needs to be considered when transformers are located in proximity to occupied areas. All energized transformers emanate sound due to the alternating flux in the core. This normal sound emitted by the transformer can be a source of annoyance unless it is kept below acceptable levels. Delta Transformers are built to meet the latest ANSI, CSA, and UL standards. These standards are outlined in the accompanying table.