Advancements in Industry: Demagnetization of Power Transformer Cores

Thomas D. Sandri, Protec Equipment ResourcesCorporate Alliance Corner, Winter 2023 Corporate Alliance Corner

After a power or distribution transformer is disconnected from the power grid or when DC current is applied, such as when a routine winding resistance measurement test is performed, the transformer core is likely to have some remnant magnetism. This remnant magnetism will increase the magnitude of the already high inrush over current levels seen when a transformer is energized. …