Laminations reduce eddy current losses by

Laminations reduce eddy current losses by

• A. By increasing magnetic permeability
• B. By forming thin insulated laminations that increase resistance to eddy currents
• C. By increasing the material conductivity
• D. By decreasing the magnetic field

Answer: (B)

Eddy currents come from changing magnetic fields inducing circulating currents in conductive material. If the core is solid, those loops can be large and carry substantial current, wasting power as heat. Forming thin insulated sheets into laminations interrupts and confines these currents: each lamination carries only tiny, high-resistance loops, and the insulation between layers prevents currents from crossing into neighboring sheets. This keeps the loop areas small and increases the resistance that the currents must travel through, so the induced currents—and the associated I^2R losses—are greatly reduced. Increasing permeability or conductivity would not reduce these circulating currents, and simply lowering the magnetic field isn’t how laminations work; the key effect is stopping and shrinking the eddy-current loops by using thin, insulated layers.

Eddy currents come from changing magnetic fields inducing circulating currents in conductive material. If the core is solid, those loops can be large and carry substantial current, wasting power as heat. Forming thin insulated sheets into laminations interrupts and confines these currents: each lamination carries only tiny, high-resistance loops, and the insulation between layers prevents currents from crossing into neighboring sheets. This keeps the loop areas small and increases the resistance that the currents must travel through, so the induced currents—and the associated I^2R losses—are greatly reduced. Increasing permeability or conductivity would not reduce these circulating currents, and simply lowering the magnetic field isn’t how laminations work; the key effect is stopping and shrinking the eddy-current loops by using thin, insulated layers.