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Midwest Current Transformers constructs most of its transformers from Cold-Rolled Grain Oriented Electrical Steel (CRGO). The CRGO electrical steel is rolled into the customer’s inner and outer diameter dimensions, allowing tight construction between layers and precise dimensioning.

CRGO electrical steel is an iron-silicon alloy that was developed to provide the low core loss and high permeability required for more efficient and economical electrical transformers. CRGO electrical steel is usually less than 2mm thick, has a silicon level of 3%, and is coated to increase electrical resistance between laminations, and to provide resistance to corrosion and rust.

Additionally, the steel is processed in such a way that the optimum properties are developed in the rolling direction, due to a tight control of the crystal orientation relative to the sheet. The special orientation of the crystals within the steel increase the magnetic flux density by approximately 30% in the coil rolling direction. This allows cores to have a higher efficiency and smaller size.