GB/T 44069.14-2025Ferrite cores - Guidelines on dimensions and the limits of surface irregularities - Part 14: EFD-cores (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents".

Drafting.

This document is Part 14 of GB/T 44069, "Limits and Limits for Dimensions and Surface Defects of Ferrite Cores". GB/T 44069 has been...

The following sections were published.

---Part 4: RM type magnetic core;

---Part 5: EP type magnetic cores and accessories for inductors and transformers;

---Part 13: PQ Type Magnetic Core;

---Part 14: EFD type magnetic core.

This document replaces GB/T 36103.14-2018 "Ferrite Core Dimensions Part 14: EFD Type Cores for Power Supplies", and is consistent with...

Compared with GB/T 36103.14-2018, apart from structural adjustments and editorial changes, the main technical changes are as follows.

---Added terms and definitions (see Chapter 3);

---Added permissible limits for surface defects in EFD type magnetic cores in accordance with relevant general specifications (see Chapter 6);

---The "Design of EFD Type Magnetic Cores" has been changed from a standard to an informative document (see Appendix A, Appendix A of GB/T 36103.14-2018).

This document is equivalent to IEC 63093-14:2019 "Limits and limits for dimensional and surface defects in ferrite cores - Part 14: EFD".

Type of magnetic core.

The following minimal editorial changes have been made to this document.

---Editing errors in Figure 4e) have been corrected;

---Notes have been added to Figure 7 and Table 5.

Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents.

This document was proposed by the Ministry of Industry and Information Technology of the People's Republic of China.

This document is under the jurisdiction of the National Technical Committee on Standardization of Magnetic Components and Ferrite Materials (SAC/TC89).

Introduction

Due to the manufacturing process and the physical characteristics of the product, ferrite cores may exhibit certain physical defects, such as chipping, irregular edges, etc.

Cracks, flash, and sticking. The tolerance for these surface defects is primarily determined by the type, location, and size of the defect, as well as the structure of the magnetic core.

GB/T 44069, "Guidelines for Limits of Dimensions and Surface Defects in Ferrite Cores," mainly specifies the core series (e.g., RM type cores, pot-shaped cores, etc.).

The limits of size and surface defects for E-type cores and toroidal cores, etc. GB/T 44069 is proposed to be divided into 15 parts.

---Part 1: General Specifications. The purpose is to establish general principles for the dimensional description and surface defect constraints of ferrite cores.

---Part 2: Pot Cores for Communication, Power Supply, and Filtering. The aim is to establish the dimensional and surface defect tolerances for pot cores.

limit.

---Part 3: Ferrite Semi-Canister Cores for Inductive Proximity Switches. The purpose is to determine the dimensions and surface defects of the semi-canister core.

Trapped to the limit.

---Part 4: RM Type Cores. The purpose is to establish the dimensional and surface defect tolerance limits for RM type cores.

---Part 5: EP-type magnetic cores and accessories for inductors and transformers. The purpose is to establish the dimensions and surface defects of EP-type magnetic cores.

Trapped to the limit.

---Part 6: ETD type magnetic cores for power supplies. The purpose is to establish the dimensional and surface defect tolerance limits for ETD type magnetic cores.

---Part 7: EER Type Cores. The purpose is to establish the dimensional and surface defect tolerance limits for EER type cores.

---Part 8: Type E Cores. The purpose is to establish the dimensional and surface defect tolerance limits for Type E cores.

---Part 9: Planar Magnetic Cores. The purpose is to establish the dimensions and permissible limits for surface defects in planar magnetic cores.

---Part 10: PM Type Cores and Accessories. The purpose is to establish the dimensional and surface defect tolerance limits for PM type cores.

---Part 11: EC Type Cores. The purpose is to establish the dimensional and surface defect tolerance limits for EC type cores.

---Part 12: Toroidal Cores. The purpose is to establish the dimensions and surface defect tolerance limits for toroidal cores.

---Part 13: PQ Type Cores. The purpose is to establish the dimensional and surface defect tolerance limits for PQ type cores.

---Part 14: EFD Type Cores. The purpose is to establish the dimensional and surface defect tolerance limits for EFD type cores.

---Part 15: U-shaped cores. The purpose is to establish the dimensional and surface defect tolerance limits for U-shaped cores.

EFD type magnetic cores have advantages such as compact structure, high power density, and low loss. They are mainly used in drive transformers, power inductors, and power transformers.

In fields such as transformers and LCD backlight transformers, this technology facilitates the flattening and miniaturization of magnetic devices. In recent years, EFD-type magnetic cores...

With increasingly widespread applications, but due to significant differences between products from different manufacturers in actual production applications, the size of EFD type magnetic cores needs to be standardized.

Standards for dimensions and surface defects help companies in this field improve technical specifications, enhance product quality, standardize production and trading practices, and promote business development.

This is of great significance to the healthy development of the industry.

Limits of Ferrite Core Size and Surface Defects Part 14: EFD Type Magnetic Core

1 Scope

This document specifies the key dimensions related to the mechanical interchangeability of the preferred series of EFD type magnetic cores, as well as the coils used with the magnetic cores.

The basic dimensions of the core skeleton and the effective parameter values used to calculate this type of magnetic core are given. Additionally, based on relevant general specifications, a table of EFD type magnetic cores is provided.

Guidelines for the tolerance limit of surface defects.

The selection of core specifications in this document is based on the principle that these specifications are determined according to industry usage, and may be included in national standards.

The standard may also be a specification widely used in the industry.

This document can be used as a sub-guideline in negotiations between core manufacturers and users regarding surface defects.

Appendix A provides general considerations for designing this type of magnetic core.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.

For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.

This document.

parts)

Note. GB/T 20874-2007 Calculation of effective parameters of magnetic parts (IEC 60205:2001, IDT) IEC 60401-1 Soft ferrite cores – Terms and definitions – Part 1: Terms and dimensions for physical defects Note. GB/T 28864.1-2012 Soft Magnetic Ferrite Core Terminology Definitions Part 1: Physical Defect Terminology (IEC 60401-1:2002, IDT) IEC 63093-11 (Limits and Limits for Dimensions and Surface Defects of Ferrite Cores) Part 1: General Specifications Note. GB/T 9634.1-2002 Guidelines for Limits of Surface Defects in Ferrite Cores Part 1: General (IEC 60424-1:1999, IDT)

1) IEC 60424-1 has been superseded by IEC 63093-1, but the contents referenced in this document still apply.

3 Terms and Definitions

The terms and definitions defined in IEC 60401-1 and IEC 63093-1 apply to this document.

ISO and IEC maintain terminology databases at the following addresses for use in standards.

4 Main Dimensions