IEC/TC 51 - IEC_TC_51

Corrigendum to EN/A1 issued April 1997

Corrigendum to EN/A1 issued April 1997

IEC 62024-1:2024 is available as IEC 62024-1:2024 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 62024-1:2024 specifies the electrical characteristics and measuring methods for the nanohenry range chip inductor that is normally used in the high frequency (over 100 kHz) range. This edition includes the following significant technical changes with respect to the previous edition: a) addition of S parameter measurement; b) addition of the inductance, Q-factor and impedance of an inductor which are measured by the reflection coefficient method with a network analyzer; c) addition of the resonance frequency of an inductor which is measured by a two-port network analyzer; d) addition of the mounting method for a surface mounting inductor with Pb-free solder.

IEC 62044-3:2023 is available as IEC 62044-3:2023 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 62044-3:2023 specifies measuring methods for power loss and amplitude permeability of magnetic cores forming the closed magnetic circuits intended for use at high excitation levels in inductors, chokes, transformers and similar devices for power electronics applications. This second edition cancels and replaces the first edition published in 2000. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: addition of Annex F and Annex G.

This standard provides the test methods for the electrical and magnetic properties of magnetic powder cores used for inductive components in electronics equipment, switch-mode power supplies and power conversion equipment, and introduces measuring principles, scope of application and matters needing attention for each method. The parameters used to characterize the magnetic powder cores include: inductance factor, effective permeability, complex relative permeability, temperature coefficient of permeability, frequency coefficient of permeability, DC bias characteristic, power loss, and quality factor. This standard is the basis for determining the characteristic parameters of magnetic powder cores.

IEC 62025-2:2019 is available as IEC 62025-2:2019 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 62025-2:2019 specifies a test method for the non-electrical characteristics of the surface mounted device (SMD) inductors to be used for electronic and telecommunication equipment. The object of this part of this document is to define methods for measuring mechanical performance only. As the reliability performances and specifications relative to non-electrical performances are defined in IEC 62211, detailed measuring methods for mechanical performance of reliability testing are defined in this document. This edition includes the following significant technical changes with respect to the previous edition: - revision of Table 5; - revision of normative references.

IEC 63299:2022 specifies classification rules for metallic magnetic powder cores used in inductive components fulfilling the requirements of the electronics industries. This document addresses the following objectives for magnetic powder cores suppliers and users: - cross-reference between core materials from multiple suppliers; - assistance to users in understanding the published technical data in catalogues when comparing multiple suppliers; - guidance to users in selecting the most applicable core for each application; - establishing uniform benchmarks for suppliers for performance in the new development of core material.

IEC 61333:2019 specifies marking locations and a coding system of marking on ferrite cores. An alphanumerical marking printed or attached to cores reduces the risk of incorrect assembly, mixing of materials and/or mixing of gapped cores on an assembly line. The markings of the inductance factor AL value or of the gap length are especially important to avoid this kind of problem, and their coding system is specified in this document. This edition includes the following significant technical changes with respect to the previous edition： a) the title of the document was changed; b) the scope of this document was expanded; c) the marking position instructions for ring cores, planar cores, RM-cores, PQ-cores and pot-cores were added in Clause 4 with a few additional descriptions; d) the four-digit-maximum limit of material identification code has been deleted in 5.2; e) in Table 1, the unit of AL has been changed from "nH" to "nH/N2".

IEC 63093-10:2022 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of PM-cores made of magnetic oxides, the main dimensions for coil formers to be used with these cores and the locations of their pins on a modular printed wiring grid in relation to the base outlines of cores. It also specifies the effective parameter values to be used in calculations and gives guidelines on allowable limits of surface irregularities applicable to the PM-cores.

This part of IEC 63093 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of EFD-cores, the essential dimensions of coil formers to be used with them, and the effective parameter values to be used in calculations involving them. It also gives guidance on the allowable limits of surface irregularities applicable to EFDcores in accordance with the relevant generic specification. The selection of core sizes for this document is based on the philosophy of including those sizes which are industrial standards, either by inclusion in national standards, or by broadbased use in industry. This document is a specification useful in the negotiation between ferrite core manufacturers and users about surface irregularities. The general considerations that the design of this range of cores is based upon are given in Annex A.

This part of IEC 63093 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of ring-cores, also called toroid cores, and the effective parameter values to be used in calculations involving them. It also gives guidelines on allowable limits of surface irregularities applicable to ring-cores. This document is a specification useful in the negotiations between ferrite core manufacturers and users about surface irregularities.

IEC 63093-4:2019 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of RM-cores and low-profile RM-cores made of ferrite, and the locations of their terminal pins on a 2,54 mm printed wiring grid in relation to the base outlines of the cores. It also gives guidance on allowable limits of surface irregularities applicable to RM-cores in accordance with the relevant generic specification. The selection of core sizes for this document is based on the philosophy of including those sizes which are industrial standards, either by inclusion in a national standard, or by broad-based use in industry. This document is a specification useful in the negotiations between ferrite core manufacturers and customers about surface irregularities. This first edition cancels and replaces the first edition of IEC 62317-4 published in 2005 and the second edition of IEC 60424-2 published in 2015. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to IEC 62317-4:2005 and IEC 60424-2:2015: a) IEC 63093-4 integrates the contents of IEC 62317-4:2005 and IEC 60424-2:2015; b) IEC 60424-2:2015, Table 2, has been included in Annex C as Table C.1.

This part of IEC 63093 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of PQ-cores and low-profile PQI-cores made of ferrite, and the locations of their terminal pins on a 2,54 mm printed wiring grid in relation to the base outlines of the cores. It also gives guidance on allowable limits of surface irregularities applicable to PQ-cores in accordance with the relevant generic specification. The selection of core sizes for this document is based on the philosophy of including those sizes which are industrial standards, either by inclusion in a national standard, or by broad-based use in industry. This document is a specification useful in the negotiations between ferrite core manufacturers and customers about surface irregularities. The general considerations that the design of this range of cores is based upon are given in Annex A.

IEC 63182-3:2021 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of E-cores made of metallic magnetic powder, the essential dimensions of coil formers to be used with them as well as the effective parameter values to be used in calculations involving them, and gives guidelines on allowable limits of surface irregularities applicable to E-cores. This document is a specification useful in the negotiations between magnetic powder core suppliers and users about surface irregularities.

IEC 63182-5:2021 specifies the preferred range of the dimensions that are of importance for mechanical interchangeability and gives the guidelines on allowable limits of surface irregularities for cylinder-cores made of metallic magnetic powder. This document is a specification useful in the negotiations between magnetic powder core suppliers and users about surface irregularities.

This part of IEC 63182 specifies the preferred range of the dimensions that are important for mechanical interchangeability and the guidelines on allowable limits of surface irregularities for block-cores made of metallic magnetic powder. This document is a specification about surface irregularities which is useful in the negotiations between suppliers and users of magnetic powder core. The use of "derived" standards which give more detailed specifications of component parts while still permitting compliance with this standard is discussed in Annex A.

IEC 63093-8:2018(E) specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of E-cores made of ferrite and the essential dimensions of coil formers to be used with them, as well the effective parameter values to be used in calculations involving them. It also gives guidelines on allowable limits of surface irregularities applicable to E-cores. The specifications contained in this document are useful in negotiations between ferrite core manufacturers and customers about surface irregularities. The use of derived standards, which give more detailed specifications of component parts while still permitting compliance with this standard, is discussed in Annex A. This edition includes the following significant technical changes with respect to IEC 62317-­8:2006 and IEC 60424-3:2015: a. This document integrates IEC 62317-8:2006 and IEC 60424-3:2015; b. Table 4 – Allowable areas of chips for E-cores, of IEC 60424-3:2015, has been moved to Annex C (informative) of this document.

IEC 63093-6:2018(E) specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of ETD-cores made of ferrite and the essential dimensions of coil formers to be used with them, as well the effective parameter values to be used in calculations involving them. It also gives guidelines on allowable limits of surface irregularities applicable to ETD-cores. The specifications contained in this document are useful in negotiations between ferrite core manufacturers and users about surface irregularities. The use of derived standards which give more detailed specifications of component parts while still permitting compliance with this document is discussed in  REF _Ref506796608 \r \h Annex A 08D0C9EA79F9BACE118C8200AA004BA90B02000000080000000E0000005F005200650066003500300036003700390036003600300038000000 . This edition includes the following significant technical changes with respect to IEC 62317-­6:2015 and IEC 60424-3:2015: a. This document integrates IEC 62317-6:2015 and IEC 60424-3:2015; b. Table 1 – Allowable areas of chips for ETD-cores, of IEC 60424-3:2015, has been moved to Annex C (informative) of this document.

IEC 63093-5:2018(E) specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of EP-cores made of ferrite, the essential dimensions of coil formers to be used with them and the locations of their terminal pins on a 2,50 mm printed wiring grid in relation to the base outlines of the cores and the effective parameter values to be used in calculations involving them. It also gives guidelines on allowable limits of surface irregularities applicable to EP-cores. The specifications contained in this document are useful in negotiations between ferrite core manufacturers and users about surface irregularities. The general considerations upon which the design of this range of cores is based are as given in Annex A. This edition includes the following significant technical changes with respect to IEC 62317-­5:2015: a. addition of the limits of surface irregularities.

IEC 63093-11:2018(E) specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of EC-cores made of ferrite and the essential dimensions of coil formers to be used with them, as well the effective parameter values to be used in calculations involving them. It also gives guidelines on allowable limits of surface irregularities applicable to EC-cores. The specifications contained in this document are useful in negotiations between ferrite core manufacturers and customers about surface irregularities. This first edition cancels and replaces the first edition of IEC 62317-11 published in 2015 and the second edition of IEC 60424-3 published in 2015. This edition constitutes a technical revision. This document includes the following significant technical changes with respect to IEC 62317­11:2015 and IEC 60424-3:2015:
This document integrates IEC 62317-11:2015 and IEC 60424­3:2015;
Table 3 – Allowable areas of chips for EC-cores, of IEC 60424-3:2015, has been moved to Annex B (informative) of this document.

IEC 63093-7:2018(E) specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of EER-cores made of ferrite, the essential dimensions of coil formers to be used with them as well the effective parameter values to be used in calculations involving them, and gives guidelines on allowable limits of surface irregularities applicable to EER-cores. This document is a specification useful in the negotiations between ferrite core manufacturers and customers about surface irregularities. The use of “derived” standards which give more detailed specifications of component parts while still permitting compliance with this document is discussed in Annex A. This first edition cancels and replaces the first edition of IEC 62317-7 published in 2005. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to IEC 62317-7: a) IEC 63093-7 integrates IEC 62317-7 and IEC 60424-3; b) IEC 60424-3:2015, Table 2, has been included in Annex C as Table C.1.

This part of IEC 62024 specifies electrical characteristics and measuring methods for the nanohenry range chip inductor that is normally used in high frequency (over 100 kHz) range.

IEC 63182-2:2020 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of ring-cores (also called toroids) made of magnetic powder, the effective parameter values to be used in calculations involving them, and gives guidelines on allowable limits of surface irregularities applicable to coated ring-cores. The selection of core sizes for this document is based on the philosophy of including those sizes which are industrial standards, meaning that they are in broad-based use within the industry. This document is considered as a sectional specification useful in the negotiations between magnetic powder core manufacturers and users about surface irregularities.

IEC 61007:2020 describes a number of tests for use in determining the significant parameters and performance characteristics of transformers and inductors for use in electronics and telecommunication equipment. These test methods are designed primarily for transformers and inductors used in all types of electronics applications that can be involved in any specification for such components. Even though these tests can be useful to the other types of transformers used in power distribution applications in utilities, industry, and others, the tests discussed in this document can supplement or complement the tests but are not intended to replace the tests in standards for transformers. Some of the tests described are intended for qualifying a product for a specific application, while others are test practices used for manufacturing and customer acceptance testing. The test methods described here include those parameters most commonly used in the electronics transformer and inductor industry: electric strength, resistance, power loss, inductance, impedance, balance, transformation ratio and many others used less frequently. This edition includes the following significant technical changes with respect to the previous edition: a) scope: the application of the scope of IEC 61007 was extended; b) Clause 2: added new references and updated the references; c) Clause 3: new definitions were added in 3.3, and in 3.7 the voltage-time product was redefined; d) test procedures were updated; e) environmental test procedures: new references were added; f) Annexes A to G were added.

IEC 63182-1:202 (E) specifies the dimensions of magnetic powder cores. This document also gives guidelines on the allowable limits of surface irregularities of magnetic powder cores. It is considered as a general specification useful in the dialogue between magnetic powder core manufacturers and users about surface irregularities. It is intended that this document will include magnetic powder cores which are widely used and referenced in industry, either because they are included in national standards, or because they are seen to have broad-based use in industry. Where applicable, it is intended that the existing industrial name for each powder core will appear with the part within the IEC 63182 series.

IEC 61631:2020 is available as IEC 61631:2020 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 61631:2020 specifies a test method for the mechanical strength of cores made of magnetic oxides. This test method is suitable for most of the E-cores, ETD-cores, I-cores and ring-cores but other core types such as U-cores could be tested according to a derived method agreed by the parties concerned. This document is also applicable to the mechanical strength measurement of magnetic powder cores. This edition includes the following significant technical changes with respect to the previous edition: - the phrase: "This document is also applicable to the mechanical strength measurement of magnetic powder cores" has been added in the scope; - IEC 61246 has been replaced by IEC 63093-8; EN 1002-2 has been replaced by ISO 7500-1; ISO 4677-1 and ISO 4677-2 have been withdrawn; - dimensions D and F in Figure A.1 and Table A.1 have been changed to be consistent with Figure 1 of IEC 63093-8:2018; - addition of the content of ring-cores test; - addition of Annex B; - the location of the jig is amended in Figure 3; - in Figure 5, the roller bars are moved to the edge of the I-core, aligned with the core.

IEC 63093-1:2020 specifies the dimensions and allowable limits of surface irregularities of ferrite cores. It is intended that this document excludes ferrite cores which are specialty cores with limited use. Also, special cores which are only marginal variations upon standard cores are excluded. IEC publishes electrical standards for families of ferrite cores, as well as this series of dimensional standards for families of ferrite cores. Modifications to the ferrite cores listed in one type of standard are reflected in the other type. This document is considered as a general specification useful in the dialogue between ferrite core suppliers and users about surface irregularities. This first edition cancels and replaces the second edition of IEC 60424-1 published in 2015 and the first edition of IEC 62317-1 published in 2007. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous editions of IEC 60424-1 and IEC 62317-1: a) this document integrates IEC 60424-1 and IEC 62317-1.

IEC 63093-9:2020 specifies the shapes and dimensions of ferrite cores for inductive components (transformers and chokes), whose the coil is typically made of multi-layer boards (or the coil is part of the motherboard), and the effective parameter values used in calculations. This document gives guidelines on allowable limits of surface irregularities applicable to planar-cores as well. This document is considered as a sectional specification useful in the negotiation between ferrite core suppliers and users about surface irregularities. This first edition cancels and replaces the first edition of IEC 60424-5 published in 2009 and first edition of IEC 62317-9 published in 2006 and its Amendment 1:2007. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous editions of IEC 60424-5 and IEC 62317-9: a) IEC 63093-9 integrates IEC 60424-5 and IEC 62317-9; b) Table 1, Table 2 and Table 3 in IEC 60424-5:2009 have been moved to Annex B; c) some numbers are corrected in Table 4; d) Table 6 is amended following IEC 60205.

IEC 60401-1:2020 is available as IEC 60401-1:2020 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 60401-1:2020 provides a nomenclature of the most frequent surface, bulk and shape irregularities relevant to cores made of soft ferrites (magnetic oxides). Most irregularities are graphically exemplified as visual aids. A general recommendation is also given in Annex A for a consistent scheme for specifying the exact location of the irregularity, combining a general name for the location with more detailed qualifiers of the specified location. This document can also be useful as a terminology reference when preparing technical documentation, irregularity inspection specifications, etc. This document also presents a method for defining the designation nomenclature for the major physical attributes of soft ferrite core shapes. The purpose of this document is to facilitate uniform usage of dimensional characters by manufacturers, specifiers, and users when describing core dimensions on drawings, in tables, and on catalogue specification sheets. This second edition cancels and replaces the first edition of IEC 60401-1 published in 2002 and the second edition of IEC 60401-2 published in 2009. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous editions of IEC 60401-1 and IEC 60401-2: - added the surface irregularity term “pores” in 4.3.1.6; - added the surface irregularity term “scratch” in 4.3.6.3; - removed the surface irregularity term “crater” in 4.1.5 of IEC 60401-1: 2002; - removed the bulk irregularity terms “superpores” in 5.1, “inclusions” in 5.2, “internal stratification” in 5.3 and “internal crack” in 5.4 of IEC 60401-1: 2002; - removed the contents related to “yoke ring cores” in 7.1.3 and 7.4 of IEC 60401-1:2002; - replaced the surface irregularity term “stratification” with “lamination” in 4.3.4.7; - replaced the location related terms “upper surface of back” with “bottom surface” and “lower surface of back” with “back surface” in Figure A.1; - changed Clause 7 of IEC 60401-1:2002 into Annex A.

IEC 63093-2:2020 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of pot-cores made of ferrite, and the dimensional limits for coil formers to be used with them, as well as the effective parameter values to be used in calculations involving them. It also gives guidelines on the allowable limits of surface irregularities applicable to pot-cores in accordance with the relevant generic specification. The selection of core sizes and shapes for this document is based on the philosophy of including those sizes which are industrial standards, either by inclusion in a national standard, or by broad-based use in industry. See IEC 62317-1 for more detail concerning the philosophy of selecting core sizes to be included. The general considerations upon which the design of this range of cores is based are given in Annex A. This first edition cancels and replaces the first edition of IEC 62317-2 published in 2010. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition of IEC 62317-2: a) addition of the limits of surface irregularities; b) Table 4 and Table 5 are updated in accordance with IEC 60205:2016.

IEC 62024-2:2020 is available as IEC 62024-2:2020 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 62024-2:2020 specifies the measuring methods of the rated direct current limits for small inductors. Standardized measuring methods for the determination of ratings enable users to accurately compare the current ratings given in various manufacturers’ data books. This document is applicable to leaded and surface mount inductors with dimensions according to IEC 62025-1 and generally with rated current less than 22 A, although inductors with rated current greater than 22 A are available that fall within the dimension restrictions of this document (no larger than a 12 mm x 12 mm footprint approximately). These inductors are typically used in DC-to-DC converters built on PCBs, for electric and telecommunication equipment, and small size switching power supply units. The measuring methods are defined by the saturation and temperature rise limitations induced solely by direct current. This edition includes the following significant technical changes with respect to the previous edition: - addition of Table 2 and Figure 2 b).

IEC 63093-3:2020 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of half pot-cores made of ferrite, intended to be used in inductive proximity switches. Half pot-cores for inductive proximity switches are also called PS-cores. The selection of core sizes and shapes for this document is based on the philosophy of including those sizes and shapes which are industrial standards, either by inclusion in a national standard, or by broad-based use in industry. This part of IEC 63093 can also be considered as a sectional specification useful in the negotiations between ferrite core manufacturers and customers about surface irregularities. It provides guidelines on the allowable limits of surface irregularities applicable to PS-cores in accordance with the relevant generic specification. This first edition cancels and replaces the first edition of IEC 62323, published in 2005. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition of IEC 62323: a) addition of the limits surface irregularities.

IEC 62211:2017(E) sets up a broad basis of electric and mechanical criteria of failure test procedures. This document is applicable to inductive components (chokes and transformers) based on magnetically soft materials. This edition includes the following significant technical changes with respect to the previous edition: a) continuous shock and mechanical shock are integrated in the test conditions; b) the normative references in Table 3 are changed.

IEC 60205:2016(E) specifies uniform rules for the calculation of the effective parameters of closed circuits of ferromagnetic material. This edition includes the following significant technical changes with respect to the previous edition: a) addition, in 5.1, of the drawing of a core of rectangular cross-section with chamfer; b) addition, in 5.1.3, of the equation of a core of rectangular cross-section with chamfer; c) equations in 5.1.4, 5.6, 5.7, 5.8, 5.9, 5.11, 5.12, 5.14 are amended or replaced; d) drawings RM6-S and RM6-R in 5.7 are amended; e) addition of EC-cores, see 5.15.

IEC 61332:2016(E) specifies classification rules for soft ferrite materials used in inductive components (inductors and transformers) fulfilling the requirements of the electronic industries. This document addresses the following issues for ferrite suppliers and users: - cross-reference between materials from multiple suppliers; - assistance to customers in understanding the published technical data in catalogues when comparing multiple suppliers; - guidance to customers in selecting the most applicable material for each application; - setting of nomenclature for IEC standards relating to ferrite; - establishing uniform benchmarks for suppliers for performance in new development of materials. This edition includes the following significant technical changes with respect to the previous edition: a) deleted "c" rank from subclass from Table 3, because of too large power loss density; b) added "a-wide" rank in subclasses PW3, PW4 and PW5 in Table 3; c) changed "B" of PW3 class from 100 mT to 200 mT; "B x f" and "power loss density" have also been changed; d) changed "B" of PW4 class from 50 mT to 100 mT; "B x f" and "power loss density" have also been changed.

IEC 61605:2016(E) specifies marking codes for fixed inductors. It covers the inductance values and their tolerances as well as dates. This edition includes the following significant technical changes with respect to the previous edition: a) The date code system for fixed inductors has been updated.

IEC 62317-12:2016(E) specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of ring-cores, also called toroid cores, and the effective parameter values to be used in calculations involving them. The selection of core sizes for this document is based on the philosophy of including those sizes which are industrial standards, meaning that they are in broad-based use within industry. See IEC 62317-1 for more detail concerning the philosophy of selecting core sizes to be included. This first edition cancels and replaces the first edition of IEC TR 61604 published in 1997. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to IEC TR 61604: a) amendment of Clause 5 concerning the relationship between standard of European, Japanese and U.S.A. sizes; b) addition of Subclause 5.3 concerning coating.

IEC 62317-6:2015 specifies the dimensions that are of importance for mechanical interchangeability for ETD-cores made of ferrite, the essential dimensions of coil formers to be used with them, and the effective parameter values to be used in calculations involving them. This first edition cancels and replaces the second edition of IEC 61185 published in 2005. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - Changed dimension A of ETD 54 core.

IEC 60401-3:2015 gives guidelines for a uniform method of presentation for the properties of magnetically soft ferrite materials and measuring conditions under which they should be determined. It is intended for use in manufacturers' catalogues of transformer and inductor cores, in order to aid the comparability of such data. Additional guidance is given for users and manufacturers concerning testing and specification of reliability for ferrite cores and for devices using ferrite cores. This edition includes the following significant technical changes with respect to the previous edition: - addition of reliability in Clause 6.

IEC 60424-4:2015 gives guidance on allowable limits of surface irregularities applicable to ring-cores in accordance with the relevant generic specification defined in IEC 60424-1. This standard is considered as a sectional specification useful in the negotiations between ferrite core manufacturers and customers about surface irregularities. This edition includes the following significant technical changes with respect to the previous edition: - addition of crystallites in 3.1.3 and of pores in 3.1.4.

IEC 60424-1:2015 gives guidelines on the allowable limits of surface irregularities of ferrite cores. This standard should be considered as a general specification useful in the dialogue between ferrite core manufacturers and customers about surface irregularities. This edition includes the following significant technical changes with respect to the previous edition: - addition of pores in 3.5 and crystallites in 3.6.

IEC 60424-2:2015 provides guidelines on the allowable limits of surface irregularities applicable to RM-cores in accordance with the relevant generic specification. This standard should be considered as a sectional specification useful in the negotiations between ferrite core manufacturers and customers about surface irregularities. Normative reference. This edition includes the following significant technical changes with respect to the previous edition: - addition of crystallites in 3.6 and of pores in 3.7.