IEC 63093-5:2025 PDF

Overview

IEC 63093-5:2025 - "Ferrite cores - Guidelines on dimensions and the limits of surface irregularities - Part 5: EP‑cores and associated parts for use in inductors and transformers" defines mechanical and visual requirements for a preferred range of EP‑cores (sizes EP5 to EP30) made of ferrite. The standard specifies the principal dimensions that ensure mechanical interchangeability, essential coil‑former dimensions, terminal‑pin locations on a 2.50 mm printed wiring grid, and the effective magnetic parameters to be used in calculations. It also gives illustrated guidance and numerical limits for allowable surface irregularities (chips, cracks, flash, pull‑outs, crystallites, pores) useful in supplier–user negotiations.

Key topics and technical requirements

• Mechanical interchangeability: Principal dimensions and tolerances for EP‑core sizes (EP5…EP30) to ensure assemblies and wound coil formers fit across suppliers.
• Coil former dimensions: Essential limits for formers that mate with EP‑cores (see main dimensions and tables for e, f, d, s, etc.).
• Pin locations and base outlines: Terminal pin coordinates referenced to a 2.50 mm PCB grid for both SMD and PTH versions, with base outlines relative to mounting direction.
• Effective parameters: Effective magnetic parameters and A‑values are tabulated (Table 2) and calculated per IEC 60205; the standard instructs use of K(nom.) for those calculations.
• Surface irregularities: Definitions, examples (figures), and numerical acceptance criteria:
  • Minimum visually distinguishable area: 0.5 mm²
  • For chips on mating surfaces, cumulative chip area must be **