IEC 63093-7:2018

Overview - IEC 63093-7:2018 (Ferrite cores - Part 7: EER‑cores)

IEC 63093-7:2018 provides guidelines on the dimensions and allowable surface irregularities for EER‑cores made of ferrite. It defines the principal and effective parameters needed for mechanical interchangeability, specifies essential dimensions for compatible coil formers, and gives visual‑inspection limits for defects such as chips, cracks, flash, pull‑outs, crystallites and pores. This edition integrates earlier documents (IEC 62317‑7 and IEC 60424‑3) and is intended to support consistent manufacture, testing and procurement of EER‑cores.

Key technical topics and requirements

• Primary dimensions and tolerances: Principal dimensions (A–F) and min/max limits for a preferred range of EER‑core sizes (e.g., EER25.5 to EER49) are listed in Table 1 to ensure mechanical interchangeability.
• Effective parameters for design calculations: Table 2 gives effective parameter and A_min values (calculated per IEC 60205) to be used in magnetic design and loss/inductance calculations.
• Coil former limits: Essential coil‑former dimensions (d1, d3, h1) suitable for specified EER‑cores are given in Table 3, facilitating correct winding and assembly.
• Surface irregularity guidelines: Visual acceptance criteria and limits for chips (minimum visible area 0.5 mm²), ragged edges, cracks, flash, pull‑outs, crystallites and pores are defined; figures and tables illustrate allowable locations and sizes.
• Inspection aids and gauges: Annex B provides example gauge dimensions and inspection procedures; Annex C includes allowable chip‑area examples and integrates IEC 60424‑3 content.

Practical applications - who uses this standard

• Ferrite core manufacturers - to set production tolerances, inspection criteria and to publish compliant product data.
• Magnetic component and transformer designers - to select cores and use the effective parameters in calculations (per IEC 60205).
• Quality, acceptance and procurement teams - for supplier specifications, incoming inspection and negotiating allowable surface irregularities.
• Coil‑former and winding houses - to ensure mechanical fit and electrical performance with standard core dimensions.
• Test and compliance engineers - to develop visual inspection and gauge‑based verification procedures.

Related standards and references

• IEC 60205 - Calculation of effective parameters of magnetic piece parts (used for Table 2 calculations)
• IEC 60401‑1 - Terms and nomenclature for ferrite core irregularities
• IEC 60424‑1 - General specification for limits of surface irregularities
• Historical: IEC 62317‑7 (replaced); IEC 60424‑3 content integrated (included as Table C.1)

Using IEC 63093‑7 helps ensure interchangeability, clarity in supplier contracts, and consistent quality control for EER‑core based magnetic components. Keywords: ferrite cores, EER‑cores, IEC 63093‑7, surface irregularities, core dimensions, coil formers, effective parameters.