IEC 63093-14:2019

Ferrite cores - Guidelines on dimensions and the limits of surface irregularities - Part 14: EFD-cores

IEC 63093-14:2019 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 EFD-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 national standards, or by broad-based use in industry.
This document is a specification useful in the negotiation between ferrite core manufacturers and users about surface irregularities.
This first edition cancels and replaces the first edition of IEC 62317-14 published in 2008. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to IEC 62317-14:2008:  
guidelines on the limits of surface irregularities of EFD-cores were added.

Noyaux ferrites - Lignes directrices relatives aux dimensions et aux limites des irrégularités de surface - Partie 14: Noyaux EFD

L’IEC 63093-14:2019 spécifie les dimensions qui présentent une importance pour l'interchangeabilité mécanique d'une plage préférentielle de noyaux EFD, les dimensions essentielles des supports de bobine à utiliser avec les noyaux EFD, ainsi que les valeurs des paramètres effectifs à utiliser dans les calculs qui impliquent ces noyaux. Elle donne également des recommandations relatives aux limites admissibles des irrégularités de surface applicables aux noyaux EFD conformément à la spécification générique correspondante.
Le choix des tailles des noyaux pour le présent document est fondé sur la philosophie consistant à introduire les tailles qui correspondent à des normes industrielles, soit par inclusion dans des normes nationales, soit par utilisation à grande échelle dans l’industrie.
Le présent document est une spécification utile à la négociation entre les fabricants et les utilisateurs de noyaux ferrites sur les irrégularités de surface.
Cette première édition annule et remplace la première édition de l’IEC 62317-14 parue en 2008. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l’IEC 62317-14:2008:
ajout de lignes directrices relatives aux limites des irrégularités de surface des noyaux EFD.

General Information

• Status: Published
• Publication Date: 03-Apr-2019
• ICS: 29.100.10 - Magnetic components
• Technical Committee: TC 51 - Magnetic components, ferrite and magnetic powder materials
• Drafting Committee: WG 1 - TC 51/WG 1
• Current Stage: PPUB - Publication issued
• Start Date: 04-Apr-2019
• Completion Date: 03-May-2019

Relations

• Replaces: IEC 62317-14:2008 - Ferrite cores - Dimensions - Part 14: EFD-cores for use in power supply applications
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 63093-14 ®
Edition 1.0 2019-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Ferrite cores – Guidelines on dimensions and the limits of surface irregularities –
Part 14: EFD-cores
Noyaux ferrites – Lignes directrices relatives aux dimensions et aux limites des
irrégularités de surface –
Partie 14: Noyaux EFD
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and
once a month by email. French extracted from the Terms and Definitions clause of
IEC publications issued since 2002. Some entries have been
IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and
If you wish to give us your feedback on this publication or CISPR.

need further assistance, please contact the Customer Service

Centre: [e-mail].
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Recherche de publications IEC - Electropedia - www.electropedia.org
webstore.iec.ch/advsearchform Le premier dictionnaire d'électrotechnologie en ligne au
La recherche avancée permet de trouver des publications IEC monde, avec plus de 22 000 articles terminologiques en
en utilisant différents critères (numéro de référence, texte, anglais et en français, ainsi que les termes équivalents dans
comité d’études,…). Elle donne aussi des informations sur les 16 langues additionnelles. Egalement appelé Vocabulaire
projets et les publications remplacées ou retirées. Electrotechnique International (IEV) en ligne.

IEC Just Published - webstore.iec.ch/justpublished Glossaire IEC - std.iec.ch/glossary
Restez informé sur les nouvelles publications IEC. Just 67 000 entrées terminologiques électrotechniques, en anglais
Published détaille les nouvelles publications parues. et en français, extraites des articles Termes et Définitions des
Disponible en ligne et une fois par mois par email. publications IEC parues depuis 2002. Plus certaines entrées
antérieures extraites des publications des CE 37, 77, 86 et
Service Clients - webstore.iec.ch/csc CISPR de l'IEC.

Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
[e-mail].
IEC 63093-14 ®
Edition 1.0 2019-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Ferrite cores – Guidelines on dimensions and the limits of surface irregularities –

Part 14: EFD-cores
Noyaux ferrites – Lignes directrices relatives aux dimensions et aux limites des

irrégularités de surface –
Partie 14: Noyaux EFD
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.100.10 ISBN 978-2-8322-6764-6

– 2 – IEC 63093-14:2019 © IEC 2019
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Primary dimensions . 7
4.1 General . 7
4.2 Dimensions of EFD-cores . 7
4.2.1 Principal dimensions . 7
4.2.2 Effective parameter and A values . 8
min
4.3 Dimensional limits for coil formers. 8
4.4 Locations of pins and base outlines . 9
4.5 Pin diameter . 12
5 Mounting . 12
6 Definitions and limits of surface irregularities . 12
6.1 General . 12
6.2 Examples of surface irregularities . 12
6.3 Chips and ragged edges . 12
6.3.1 General . 12
6.3.2 Chips and ragged edges located on the mating surface . 12
6.3.3 Chips and ragged edges located on other surfaces . 13
6.4 Cracks . 15
6.5 Pull-out . 16
6.6 Crystallites . 16
6.7 Flash . 16
6.8 Pores . 17
Annex A (informative) EFD-core design . 18
Annex B (informative) Limits for allowable chipping areas . 19

Figure 1 – Dimensions of EFD-cores . 7
Figure 2 – Main dimensions of coil formers for EFD-cores . 8
Figure 3 – Locations of pins (SMD type) viewed from the upper side of the board . 10
Figure 4 – Locations of pins (PTH type) viewed from the upper side of the board . 11
Figure 5 – Examples of surface irregularities . 12
Figure 6 – Locations of chips and ragged edges . 13
Figure 7 – Locations of cracks . 15
Figure 8 – Location of pull-out . 16
Figure 9 – Location of crystallite . 16
Figure 10 – Location of flash . 17
Figure 11 – Location of pore . 17

Table 1 – Dimensions of EFD-cores . 7
Table 2 – Effective parameter and A values for EFD-cores . 8
min
Table 3 – Dimensional limits of coil formers for EFD-cores . 9
Table 4 – Area and length reference of irregularities for visual inspection . 14
Table 5 – Limits for cracks . 15
Table B.1 – Limits for allowable chipping areas. 19

– 4 – IEC 63093-14:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FERRITE CORES –
GUIDELINES ON DIMENSIONS AND
THE LIMITS OF SURFACE IRREGULARITIES –

Part 14: EFD-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 concerning 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)”). Their 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 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 relevant 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 the 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 maximum 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 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 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
expenses 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) Attention 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 63093-14 has been prepared by IEC technical committee 51:
Magnetic components, ferrite and magnetic powder materials.
This first edition cancels and replaces the first edition of IEC 62317-14 published in 2008.
This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to
IEC 62317-
14:2008:
a) guidelines on the limits of surface irregularities of EFD-cores were added.

The text of this International Standard is based on the following documents:
FDIS Report on voting
51/1272A/FDIS 51/1286/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 63093 series, published under the general title Ferrite cores –
Guidelines on dimensions and the limits of surface irregularities, can be found on the IEC
website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 63093-14:2019 © IEC 2019
FERRITE CORES –
GUIDELINES ON DIMENSIONS AND
THE LIMITS OF SURFACE IRREGULARITIES –

Part 14: EFD-cores
1 Scope
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 EFD-
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 national standards, or by broad-
based 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.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60205, Calculation of the effective parameters of magnetic piece parts
IEC 60401-1, Terms and nomenclature for cores made of magnetically soft ferrites – Part 1:
Terms used for physical irregularities
IEC 60424-1, Ferrite cores – Guidelines on the limits of surface irregularities – Part 1:
General specification
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60401-1 and
IEC 60424-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp

4 Primary dimensions
4.1 General
Compliance with the following requirements ensures mechanical interchangeability of
complete assemblies and wound coil formers.
4.2 Dimensions of EFD-cores
4.2.1 Principal dimensions
The principal dimensions of EFD-cores shall be as given in Figure 1 and Table 1.

a
The K dimension designates, with respect to the base level of the core, the difference in height between the
base level of the core and the underside of the centre leg. In the typical case, the underside of the centre leg is
above the base level of the core, and the value of K is positive. In the case where the underside of the centre
leg is below the base level of the core, then the value of K will be negative.
a) EFD 10/5/3, EFD 12/6/3,5 and EFD 15/8/5 b) EFD 20/10/7, EFD 25/13/9 and EFD 30/15/9
Figure 1 – Dimensions of EFD-cores
Table 1 – Dimensions of EFD-cores
A B C D E F F K q
1 2
Size
mm mm mm mm mm mm mm mm mm
Min. 10,20 5,10 2,60 3,60 7,40 4,40 1,40
EFD 10/5/3 Nom.    -0,20 0,20
Max. 10,80 5,30 2,80 3,90 7,90 4,70 1,50
Min. 12,20 6,10 3,40 4,40 8,75 5,25 1,90
EFD 12/6/3,5 Nom.    -0,20 0,20
Max. 12,80 6,30 3,60 4,70 9,25 5,55 2,10
Min. 14,60 7,35 4,50 5,25 10,65 5,15 2,30
EFD 15/8/5 Nom.    -0,20 0,45
Max. 15,40 7,65 4,80 5,75 11.35 5,45 2,50
Min. 19,45 9,85 6,50 7,45 14,90 8,70 3,45
EFD 20/10/7 Nom.    0,17 0,75
Max. 20,55 10,15 6,80 7,95 15,90 9,10 3,75
Min. 24,35 12,35 8,90 9,05 18,10 11,20 5,05
EFD25/13/9 Nom.    0,60 1,00
Max. 25,65 12,65 9,30 9,55 19,30 11,60 5,35
Min. 29,20 14,85 8.90 10,90 21,65 14,35 4,75
EFD 30/15/9 Nom.    0,75 1,00
Max. 30,80 15,15 9.30 11,50 23,15 14,85 5,05
NOTE The dimensions of the cores can be checked by means of gauges.

– 8 – IEC 63093-14:2019 © IEC 2019
4.2.2 Effective parameter and A values
min
The effective parameter values for cores having the dimensions given in 4.2.1 are as shown
in Table 2. The definitions of effective parameters and their calculations shall be as given
in IEC 60205.
Table 2 – Effective parameter and A values for EFD-cores
min
a
C C A L V A
1 2 e e e min
Size
–1 –3 2 3 2
mm mm mm mm mm mm
EFD 10/5/3 3,301 8 0,459 50 7,19 23,7 170 6,52
EFD 12/6/3,5 2,495 8 0,218 71 11,4 28,5 325 10,7
EFD 15/8/5 2,263 3 0,149 51 15,1 34,3 519 12,3
EFD 20/10/7 1,536 6 0,050 025 30,7 47,2 1 450 30,6
EFD 25/13/9 0,995 25 0,017 301 57,5 57,3 3 290 57,3
EFD 30/15/9 0,980 56 0,014 147 69,3 68,0 4 710 69,2
a
See IEC 60205.
4.3 Dimensional limits for coil formers
The main dimensions of coil formers suitable for use with a pair of EFD-cores shall be as
given in Figure 2 and Table 3.

Figure 2 – Main dimensions of coil formers for EFD-cores

Table 3 – Dimensional limits of coil formers for EFD-cores
a
e f f d S S C R
1 2 1 2
Size mm mm mm mm mm mm mm mm
Max. Min. Min. Max. Min. Min. Nom. Nom.
EFD 10/5/3 7,3 4,8 1,6 7,1 0,35 0,30 0,2 0,8
EFD 12/6/3,5 8,65 5,6 2,15 8,7 0,42 0,30 0,2 0,8
EFD 15/8/5 10,4 5,55 2,6 10.55 0.45 0,40 0,45 1,5
EFD 20/10/7 14,8 9,2 3,8 14.8 0,40 0,40 0,75 2,0
EFD 25/13/9 18,0 11,7 5,4 18,0 0,55 0,55 1,0 2,0
EFD 30/15/9 21,6 14,9 5,1 21,7 0,50 0,60 1,0 2,0
a
Chamfer.
4.4 Locations of pins and base outlines
These shall be as shown in Figure 3 and Figure 4, in which the base is viewed in the
mounting direction, i.e. from the upper side of the printed wiring board.

– 10 – IEC 63093-14:2019 © IEC 2019
Dimensions in millimetres
a) EFD 10/5/3* b) EFD 2/6/3,5* c) EFD 15/8/5* d) EFD 15/8/5* (ten pins)
(eight pins)
e) EFD 15/8/5* (ten pins) f) EFD 15/8/5** (twelve pins) g) EFD 20/10/7* (eight pins)

h) EFD 20/10/7* (ten pins) i) EFD 20/10/7** (twelve pins) j) EFD 25/13/9** (twelve pins)
NOTE * J terminals
** Gull wing terminals
Figure 3 – Locations of pins (SMD type) viewed from the upper side of the board

Dimensions in millimetres
a) EFD 15/8/5
b) EFD 20/10/7 (eight pins) c) EFD 20/10/7 (ten pins)

d) EFD 25/13/9 e) EFD 30/15/9
Figure 4 – Locations of pins (PTH type) viewed from the upper side of the board

– 12 – IEC 63093-14:2019 © IEC 2019
4.5 Pin diameter
Coil former pins (terminations) of through-hole type (PTH type) shall be accepted by a gauge
having 1,3 mm holes on a true position.
5 Mounting
Concerning EFD-cores, no mounting assemblies are defined, although various mounting
assembly clamps are offered commercially. It is recommended that the two cores be fixed by
glue, by adhesive tape, or by mounting assembly clamps.
6 Definitions and limits of surface irregularities
6.1 General
Surface irregularities are defined in IEC 60424-1.
6.2 Examples of surface irregularities
Figure 5 shows examples of surface irregularities on an EFD-core.

Figure 5 – Examples of surface irregularities
6.3 Chips and ragged edges
6.3.1 General
The minimum chipping area is taken as 0,5 mm , to be distinguishable to the naked eye.
The maximum chipping area is taken as 15 mm , to be referenced to the design of the cores.
6.3.2 Chips and ragged edges located on the mating surface
The areas of the chips located on the mating surface (see C1 and C1’ irregularities in Figure 6)
shall not exceed the following limits:
– the cumulative area of the chips shall be less than 4 % of the relevant mating surface. The
mating surface of each outer leg and centre post is considered separately.

The total length of the ragged edges shall be less than 25 % of the perimeter of the relevant
mating surface.
6.3.3 Chips and ragged edges located on other surfaces
The areas of the chips located on other surfaces shall not exceed the following limits:
– the allowable chipping areas (see C2, C2’, C3 and C3’ irregularities in Figure 6) are
doubled as compared to the limits for the whole mating surfaces (see Table B.1);
– the rule for the ragged edges is the same as for the mating surfaces;
– chips and ragged edges are not acceptable on the inner edges of the wire slot area.

a) Front area b) Back area
Figure 6 – Locations of chips and ragged edges
The limits for allowable chipping areas of EFD-cores are given in Annex B.
Area and length reference of irregularities for visual inspection are given in Table 4.

– 14 – IEC 63093-14:2019 © IEC 2019
Table 4 – Area and length reference of irregularities for visual inspection

6.4 Cracks
The limits for cracks at various locations shall not exceed the following limits:
– a single crack which intersects the perimeter of the relevant surface at two points is not
acceptable (see S1 in Figure 7).
The limits of cracks at various locations shown in Figure 7 are given in Table 5.

a) Front area b) Back area
Figure 7 – Locations of cracks
Table 5 – Limits for cracks
a
Type Location Limits for single crack Limits for multiple cracks
S1 Mating surface of centre post 25 % × F 50 % × F
2 2
S1’ Corner of centre post Not acceptable Not acceptable
S2 Mating surface of outer leg 25 % × H 25 % × H
S2’ Mating surface of outer leg 20 % × W 40 % × W
S2” Side of outer leg 25 % × H 25 % × H
S3 Centre post 25 % × F 25 % × F
2 2
Bottom corner of centre post/back
S3’ 25 % × F 25 % × F
2 2
wall and outer leg/back wall
S3’’ Centre post 25 % × F 50 % × F
1 1
Bottom corner of outer leg/back
S4 25 % × T 25 % × T
wall
S4’ Back wall
50 % × W 100 % × T
S5 Outer leg 25 % × W 25 % × W
S6 Any place Not acceptable Not acceptable
S7 Corner of outer leg Not acceptable Not acceptable
S8 Bottom surface
25 % × T 50 % × T
S9 Back surface 50 % × W 100 % × W
S9’ Back surface
25 % × W 25 % × W
a
See Figure 7.
– 16 – IEC 63093-14:2019 © IEC 2019
6.5 Pull-out
The cumulative area of the pull-out located on the bottom surface shall be less than 25 % of
the total respective surface area (see Figure 8).

Figure 8 – Location of pull-out
6.6 Crystallites
The area of the crystallites shall not exceed the following limits (see Figure 9):
– 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.
Figure 9 – Location of crystallite
6.7 Flash
The flash height shall not exceed the following limits (see Figure 10):
– with chamfering around the back surface, the flash height shall not exceed the back
surface of the core.
Figure 10 – Location of flash
6.8 Pores
The number of pores and the area of the pores shall not
...