Noise level can be below NEMA for various reasons (A & B evaluation factors, higher grade electrical steel as examples). In general, there is no way to determine the percentage of units that are below without actual test results. Typically, ABB transformers have much lower noise levels than NEMA. The NEMA levels were based on the performance of transformers that had cores made with regular grain oriented steels, operating at high flux density, and having non step lap core joints. Because noise levels required by local and state noise ordinances are now much lower than ever before, we design these transformers using highly grain oriented steels, at lower flux densities, and with step lap joints resulting in 10 - 20 lower noise levels than the NEMA TR1 table levels. How much lower is determined by what customers require based on where the transformers will be located.
Large and medium power transformers
If you want to purchase a product, need any pricing information or need help or support from ABB, please contact your local partner.