1、BSI Standards PublicationBS EN 60424-4:2016Ferrite cores Guidelines on the limits of surface irregularitiesPart 4: Ring-coresNational forewordThis British Standard is the UK implementation of EN 60424-4:2016. It is identical to IEC 60424-4:2015. It supersedes BS EN 60424-4:2001 which is withdrawn.BR
2、ITISH STANDARDBS EN 60424-4:2016The UK participation in its preparation was entrusted to Technical Committee EPL/51, Transformers, inductors, magnetic components and ferrite materials.A list of organizations represented on this committee can be obtained on request to its secretary.This publication d
3、oes not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.ISBN 978 0 580 82414 2ICS 29.100.10This British Standard was published under the authority of the
4、Standards Policy and Strategy Committee on 31 March 2016. The British Standards Institution 2016. Published by BSI Standards Limited 2016.Amendments and Corrigenda issued since publication Date Text affectedEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 60424-4 March 2016 ICS 29.100.10 Superse
5、des EN 60424-4:2001 English Version Ferrite cores - Guidelines on the limits of surface irregularities - Part 4: Ring-cores (IEC 60424-4:2015) Noyaux ferrites - Lignes directrices relatives aux limites des irrgularits de surface - Partie 4: Noyaux toriques (IEC 60424-4:2015) Ferritkerne - Leitfaden
6、fr Grenzwerte von sichtbaren Beschdigungen der Kernoberflche - Teil 4: Ringkerne (IEC 60424-4:2015) This European Standard was approved by CENELEC on 2016-01-08. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Stan
7、dard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member. This European Standard exists in three official versions (En
8、glish, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees
9、of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Sloveni
10、a, Spain, Sweden, Switzerland, Turkey and the United Kingdom. European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2016 CENELEC All rig
11、hts of exploitation in any form and by any means reserved worldwide for CENELEC Members. Ref. No. EN 60424-4:2016 E BS EN 60424-4:2016EN 60424-4:2016 2 European foreword The text of document 51/1109/FDIS, future edition 2 of IEC 60424-4, prepared by IEC/TC 51 “Magnetic components and ferrite materia
12、ls“ was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 60424-4:2016. The following dates are fixed: latest date by which the document has to beimplemented at national level bypublication of an identical nationalstandard or by endorsement(dop) 2016-10-08 latest date by which
13、 the nationalstandards conflicting with thedocument have to be withdrawn(dow) 2019-01-08 This document supersedes EN 60424-4:2001. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC and/or CEN shall not be held responsible fo
14、r identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 60424-4:2015 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following notes have to be added for the standards indicated
15、: IEC 60424-1 NOTE Harmonized as EN 60424-1. BS EN 60424-4:2016 2 IEC 60424-4:2015 IEC 2015 CONTENTS FOREWORD . 3 1 Scope 5 2 Normative references 5 3 Limits of surface irregularities 5 3.1 Uncoated ring-cores 5 3.1.1 General . 5 3.1.2 Chips and ragged edges 5 3.1.3 Cracks and pull-out 6 3.1.4 Cryst
16、allites 6 3.1.5 Pores . 7 3.2 Coated ring-cores . 7 3.2.1 General . 7 3.2.2 Coating features 7 3.2.3 Coating performance . 8 3.3 Area and length reference for visual inspection . 8 Bibliography 10 Figure 1 Chips and ragged edges location on ring-cores 6 Figure 2 Cracks and pull-out location on ring-
17、cores 6 Figure 3 Crystallites location for ring-cores 7 Figure 4 Pores location for ring-cores 7 Table 1 Area and length reference for visual inspection . 9 BS EN 60424-4:2016IEC 60424-4:2015 IEC 2015 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ FERRITE CORES GUIDELINES ON THE LIMITS OF SURFACE IRR
18、EGULARITIES Part 4: Ring-cores FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions co
19、ncerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). T
20、heir preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates
21、 closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the r
22、elevant subjects since each technical committee has representation from all interested IEC National Committees. 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that t
23、he technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maxi
24、mum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC itself does not provide any attestation of conformity. Independent certification bodies
25、provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC
26、 or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and exp
27、enses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications. 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Att
28、ention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 60424-4 has been prepared IEC technical committee 51: Magnetic compone
29、nts and ferrite materials. This second edition cancels and replaces the first edition published in 2001. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) addition of crystallites in 3.1.3 and of
30、pores in 3.1.4. BS EN 60424-4:2016 4 IEC 60424-4:2015 IEC 2015 The text of this standard is based on the following documents: FDIS Report on voting 51/1109/FDIS 51/1124/RVD Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above ta
31、ble. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of all parts in the IEC 60424 series, published under the general title Ferrite cores Guidelines on the limits of surface irregularities, can be found on the IEC website. Future standards in this series
32、will carry the new general title as cited above. Titles of existing standards in this series will be updated at the time of the next edition. The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC website under “http:/webst
33、ore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or amended. BS EN 60424-4:2016IEC 60424-4:2015 IEC 2015 5 FERRITE CORES GUIDELINES ON THE LIMITS OF SURFACE IRREGULARITIES Part 4: Ring-cores 1 Sc
34、ope This part of IEC 60424 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 manu
35、facturers and customers about surface irregularities. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest e
36、dition of the referenced document (including any amendments) applies. Void. 3 Limits of surface irregularities 3.1 Uncoated ring-cores 3.1.1 General Generally, uncoated ring-cores are smoothed (for example: by tumbling) to remove any significant flash and to add radius to edges that would otherwise
37、be sharp due to tooling angles. Tooling angles exist where the compaction punches meet the interior of the die mold, where a sharp angle in the edge of the piece that is formed is unavoidable. This is also the location inside the ferrite tool set where flashing may occur. The purpose of removing fla
38、sh and rounding edges is to allow uncoated ring cores to be wound with insulated wire, using typical production winding processes, without damage to the wire. 3.1.2 Chips and ragged edges Figure 1 shows examples of chips and ragged edges location on ring-cores. Ragged edges as defined in IEC 60424-1
39、 are allowed. Chips shall not exceed 25 % of the wall thickness either in length or in width, up to a maximum of 2 mm. The maximum number of chips shall not exceed 3 on one core edge and a total of 5 on all edges. BS EN 60424-4:2016 6 IEC 60424-4:2015 IEC 2015 Figure 1 Chips and ragged edges locatio
40、n on ring-cores 3.1.3 Cracks and pull-out Figure 2 shows examples of cracks and pull-out location on ring-cores. Cracks (C1) perpendicular to the magnetic flux path are allowed but shall not exceed 20 % of the wall thickness. Cracks (C2) parallel to the magnetic flux are allowed but shall not exceed
41、 12,5 % (1/8) of the relevant core circumference. Crazing (C3) which is a grid-like pattern of superficial cracks (e.g. depth less than 0,5 mm) is allowed. Pull-out (C4) is allowed but the relevant cumulative area on each affected core surface shall not exceed 25 % of its area. Excess dirt or ferrit
42、e debris on the surface or in the window of uncoated ring-cores is not acceptable. NOTE In any case, cores with surface irregularities will meet relevant electrical specifications. Figure 2 Cracks and pull-out location on ring-cores 3.1.4 Crystallites Figure 3 shows examples of crystallites location
43、 on ring-cores. A single area of the crystallites located on any surface shall be less than 2 % of the respective surface area. The cumulative area of the crystallites located on any surface shall be less than 4 % of the respective surface area. IEC Pull-out (C4) Cracks (C1) Crazing (C3) Cracks (C2)
44、 IEC Chips Wall-thickness Ragged edges BS EN 60424-4:2016IEC 60424-4:2015 IEC 2015 7 Figure 3 Crystallites location for ring-cores 3.1.5 Pores Figure 4 shows examples of pores location on ring-cores The number of pores located on the same surface shall not exceed 2. The total number of pores located
45、 on all surfaces shall not exceed 5. A hole with area larger than 1 mm2on any surface is not acceptable. Figure 4 Pores location for ring-cores 3.2 Coated ring-cores 3.2.1 General Coated ring-cores are generally smoothed (e.g. by tumbling) before the coating process. A variety of materials are used
46、to provide dielectric protection by coating the surfaces of the ring cores to form a barrier. These include epoxies, polyurethanes, nylons, and paraxylylenes. 3.2.2 Coating features A rough coating surface is acceptable provided that 1) dimensional specifications are met, and 2) the coating does not
47、 exhibit sharp features that would damage insulated wire that is applied using typical winding processes. Excess dirt or ferrite debris on the surface or in the window of coated ring-cores is not acceptable. Partial coating exposing bare core is unacceptable. Chips in a layer or layers of coating, e
48、xposing other coating, but not the bare core, are acceptable if they do not create sharp edges, and if the voltage breakdown limit is met. IEC Pore IEC Crystallites BS EN 60424-4:2016 8 IEC 60424-4:2015 IEC 2015 Pin holes in the surface of coated ring cores are acceptable, provided that they meet th
49、e relevant voltage breakdown specification. Air bubbles under the coating are not acceptable. Sharp flashing arising from the method of applying coating is not acceptable. Paraxylylene coatings may show varying appearance, ranging from transparent to milky white, within individual production batches, and from batch to batch. This is acceptable, provided that the relevant voltage breakdown specification is met. 3.2.3 Coating performance Coated ring-cores shall wit
