IEC 63182-8:2025

Overview

IEC 63182-8:2025 - "Magnetic powder cores - Guidelines on dimensions and the limits of surface irregularities - Part 8: U-cores" specifies the key geometric dimensions and acceptable surface irregularities for a preferred range of U-cores made from metallic magnetic powder. The standard focuses on ensuring mechanical interchangeability of cores and provides guidance for negotiations between magnetic powder core manufacturers and their customers. It also references calculation of effective magnetic parameters (per IEC 60205) and discusses the use of more detailed, “derived” standards (Annex A).

Key topics and requirements

• Primary dimensions and tolerances: Main dimensions (A, B, C, D, E, L) and a preferred size range for many common U-core types are defined. Typical tolerance guidance is provided (e.g., dimensions A and B ≈ 3.0% of center value; C ≈ 3.5%; E and L ≈ 4.0%).
• Effective parameters: Effective magnetic parameters (Ae, le, Ve, etc.) are specified for U-cores that meet the dimension table; calculations follow IEC 60205. Suppliers may list more precise values in catalogues.
• Surface irregularities: Clear visual acceptance limits are defined for defects such as chips, ragged edges, cracks, flash, rust and discoloration. Examples and locations are illustrated in figures.
  • Chips: Minimum observable chip area = 0.5 mm²; maximum cumulative chip area on a surface = 50 mm². For mating surfaces, cumulative chip area