Magnetvälju

Magnetvälju, or magnetic leakage, refers to stray magnetic flux that escapes from a magnetically closed circuit or device into the surrounding space. In an ideal magnetic circuit, all flux would follow the intended path, but real materials and geometries introduce imperfections that create high-reluctance paths such as air gaps, joints, cracks, or material inhomogeneities. The result is a portion of the flux that does not contribute to the desired magnetic effect and instead appears as an external stray field.

Causes of magnetvälju include mechanical clearances in assemblies, partial saturation of ferromagnetic parts, temperature-dependent changes in permeability, and defects in manufacturing. The presence of leakage flux can influence nearby components, cause electromagnetic interference, and contribute to energy losses in machines. In some contexts, leakage flux is also used diagnostically: magnetic-flux leakage methods exploit the leakage field near surface flaws to detect cracks, corrosion, or other defects.

In engineering practice, leakage is quantified in concepts such as leakage inductance in electrical machines, or in nondestructive testing as part of magnetic flux leakage (MFL) techniques. Modeling relies on magnetic circuit theory, finite element analysis, and empirical data to estimate leakage paths and their effects on performance.

Mitigation focuses on closing the magnetic circuit and reducing reluctance along unintended paths. Methods include using high-permeability materials, minimizing air gaps, optimizing geometry and lamination, employing magnetic shields, and carefully aligning magnetization directions. Understanding magnetvälju is important for reliable device design, sensor placement, and defect detection.