How can transformer sound be controlled?
A. All energized transformers “hum”. This “hum” is due to the alternating flux in the core producing a phenomenon known as magnetostriction. Transformer “hum” , commonly referred to as “noise”, is primarily produced by the core at a fundamental frequency of twice the applied frequency. Noise is an inherent characteristic of the core and cannot be completely eliminated. Hevi-Duty utilizes the highest quality core steel in its complete line of dry type transformers, to minimize audible sound levels. When selecting a transformer, make certain that the sound levels presented by the manufacturer have been measured in accordance with the American National Standards Institute, and certified by the manufacturer. NEMA Publication No. ST20 and ANSI Standard C89.2 establishes maximum sound levels for dry type transformers.
