IEC 62317-4:2005

Ferrite cores - Dimensions - Part 4: RM-cores and associated parts

IEC 62317-4:2005 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 specifies the test conditions and clamping forces to be used for inductance measurement. This international standard cancels and replaces the second edition of IEC 60431 published in 1983, its amendment 1 (1995), and its amendment 2 (1996). This international standard constitutes a technical revision of IEC 60431. The contents of the corrigendum of July 2016 have been included in this copy.

Noyaux ferrites - Dimensions - Partie 4: Noyaux RM et pièces associées

La CEI 62317-4:2005 spécifie les dimensions qui présentent une importance pour l'interchangeabilité mécanique d'une gamme préférentielle de noyaux RM et de noyaux RM faible hauteur en ferrite, et l'emplacement de leurs broches de raccordement sur une grille à pas de 2,54 mm en rapport avec le périmètre d'embase des noyaux. Elle spécifie également les conditions d'essai et les forces d'assemblage à utiliser pour mesurer l'inductance. La présente Norme internationale annule et remplace la deuxième édition de la CEI 60431 publiée en 1983, ainsi que son amendement 1 (1995) et son amendement 2 (1996). La présente Norme internationale constitue une révision technique de la CEI 60431. Le contenu du corrigendum de juillet 2016 a été pris en considération dans cet exemplaire.

General Information

• Status: Replaced
• Publication Date: 22-Sep-2005
• ICS: 29.100.10 - Magnetic components
• Technical Committee: TC 51 - Magnetic components, ferrite and magnetic powder materials
• Drafting Committee: MT 1 - TC 51/MT 1
• Current Stage: DELPUB - Deleted Publication
• Start Date: 31-Mar-2017
• Completion Date: 08-Mar-2019

Relations

• Replaced By: IEC 63093-4:2019 - Ferrite cores - Guidelines on dimensions and the limits of surface irregularities - Part 4: RM-cores
• Effective Date: 05-Sep-2023
• Corrected By: IEC 62317-4:2005/COR1:2016 - Corrigendum 1 - Ferrite cores - Dimensions - Part 4: RM-cores and associated parts
• Effective Date: 05-Sep-2023

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD 62317-4
First edition
2005-09
Ferrite cores – Dimensions –
Part 4:
RM-cores and associated parts
Reference number
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the

60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.

Consolidated editions
The IEC is now publishing consolidated versions of its publications. For example,

edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the

base publication incorporating amendment 1 and the base publication incorporating

amendments 1 and 2.
Further information on IEC publications
The technical content of IEC publications is kept under constant review by the IEC,
thus ensuring that the content reflects current technology. Information relating to
this publication, including its validity, is available in the IEC Catalogue of
publications (see below) in addition to new editions, amendments and corrigenda.
Information on the subjects under consideration and work in progress undertaken
by the technical committee which has prepared this publication, as well as the list
of publications issued, is also available from the following:
• IEC Web Site (www.iec.ch)
• Catalogue of IEC publications
The on-line catalogue on the IEC web site (www.iec.ch/searchpub) enables you to
search by a variety of criteria including text searches, technical committees
and date of publication. On-line information is also available on recently issued
publications, withdrawn and replaced publications, as well as corrigenda.
• IEC Just Published
This summary of recently issued publications (www.iec.ch/online_news/ justpub)
is also available by email. Please contact the Customer Service Centre (see
below) for further information.
• Customer Service Centre
If you have any questions regarding this publication or need further assistance,
please contact the Customer Service Centre:

Email: [e-mail]
Tel: [phone]
Fax: [phone]
INTERNATIONAL IEC
STANDARD 62317-4
First edition
2005-09
Ferrite cores – Dimensions –
Part 4:
RM-cores and associated parts
 IEC 2005  Copyright - all rights reserved
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 the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale S
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue

– 2 – 62317-4  IEC:2005(E)
CONTENTS
FOREWORD.3

1 Scope.5

2 Normative references.5

3 Primary standards.5

3.1 Pin locations and base outlines.5
3.2 Dimensions of RM-cores.5
3.3 Shape of coil former and pin numbering .6
3.4 Effective parameter values .6
3.5 Spring recess .6
3.6 Stud recess .6
4 Derived standards.10
5 Main dimensions for coil formers.13
5.1 RM-cores for primary standard.13
5.2 RM-cores intended particularly for power applications .15

Annex A (informative) RM-core design .18
Annex B (normative) Guidance for measuring clamping forces relevant to RM-core tests .20

Bibliography .22

62317-4  IEC:2005(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

___________
FERRITE CORES – DIMENSIONS –
Part 4: RM-cores and associated parts

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all
national electrotechnical committees (IEC National Committees). The object of the 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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment
declared to be in conformity with an IEC Publication.
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 62317-4 has been prepared IEC technical committee 51: Magnetic
components and ferrite materials.

This international standard cancels and replaces the second edition of IEC 60431 published in
1983, its amendment 1 (1995), and its amendment 2 (1996). This international standard
constitutes a technical revision of IEC 60431.
The main changes with respect to the previous edition of IEC 60431 are listed below:
－ low-profile RM-cores at present defined in IEC 61860 are added to this standard.
IEC 61860 will eventually be replaced by IEC 62317-9 which is under consideration. IEC 62317-9
will not include the low-profile RM-cores.

– 4 – 62317-4  IEC:2005(E)
The text of this standard is based on the following documents:

FDIS Report on voting
51/833/FDIS 51/839/RVD
Full information on the voting for the approval of this standard can be found in the report on voting

indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

IEC 62317 consists of the following parts, under the general title Ferrite cores – Dimensions:
Part 1: General (under consideration)
Part 2: Pot cores (under consideration, currently available as IEC 60133)
Part 3: Half pot cores (under consideration, currently available as IEC 62323)
Part 4: RM-cores and associated parts
Part 5: EP-cores (under consideration, currently available as IEC 61596)
Part 6: ETD-cores (under consideration, currently available as IEC 61185)
Part 7: EER-cores
Part 8: E-cores
Part 9: Planar cores
Part 10: PM-cores (under consideration, currently available as IEC 61247)
Part 11: EC-cores (under consideration, currently available as IEC 60647)
Part 12: Uncoated ring cores (under consideration, currently available as IEC 61604)

The committee has decided that the contents of this publication will remain unchanged until the
stability date indicated on the IEC web site under "http://webstore.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.
A bilingual version of this publication may be issued at a later date.

The contents of the corrigendum of July 2016 have been included in this copy.

62317-4  IEC:2005(E) – 5 –
FERRITE CORES – DIMENSIONS –
Part 4: RM-cores and associated parts

1 Scope
This part of IEC 62317 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 specifies the test conditions and clamping forces to be used for
inductance measurement.
The general considerations that the design of this range of cores is based upon are given in
Annex A.
2 Normative references
The following referenced documents are indispensable for the application 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 60097:1991, Grid system for printed circuits
IEC 60205:2001, Calculation of the effective parameters of magnetic piece parts
3 Primary standards
Compliance with the following requirements ensures mechanical interchangeability of complete
assemblies and wound coil formers.
3.1 Pin locations and base outlines
These shall be as shown in Figure 6 and Figure 8 (for power applications), in which the base is
viewed from the pin side, i.e. from the underside of the printed wiring boards.
The pins shall fit into holes according to IEC 60097, the nominal hole diameter being:

– 1 mm when the shortest distance between pins is 2,54 mm;
– 1,3 mm when the shortest distance between pins is 2,54 2 mm or more.
3.2 Dimensions of RM-cores
The dimensions of RM-cores shall be as given in Table 1 and the low-profile RM-cores shall be as
given in Table 2.
– 6 – 62317-4  IEC:2005(E)
3.3 Shape of coil former and pin numbering

When the coil former is viewed from the pin side, the pins shall be numbered in a clockwise

direction. Pin 1 shall be a corner pin, or the pin immediately to the right of a corner, and closest to

the base outline.
For asymmetrical arrangements, pin 1 shall be at the side with the largest number of pins. The

coil former shall show an asymmetry which shall preferably be visible (or detectable) when the

assembled inductor is held with the pins downwards. This asymmetry shall clearly indicate pin 1.

For pin numbering of recommended core patterns and for recommended asymmetrical pin

arrangements, see 3.1.
NOTE It is not required that the pin numbers be marked on the coil former.
3.4 Effective parameter values
The effective parameter values for cores having the dimensions given in 3.2 and 3.5 are as shown
in Table 3 and Table 4.
3.5 Spring recess
RM-cores shall have recesses which allow the core halves to be held together by two spring
clamps snapping into these recesses. The recesses consist of a flat spring rest and a locking
ridge. The dimensions are given in Table 5; the profile of this spring recess is not defined but the
limit dimensions shall be complied with.
3.6 Stud recess
Those RM-cores with centerpost holes may have recesses for the fixed part of the adjusting
device with dimensions in accordance with Table 6. These dimensions are not mandatory for
manufacturers who supply cores with the fixed part of the adjusting device attached.

62317-4  IEC:2005(E)                    – 7 –

The dimensions specified in Table 1 are illustrated in Figure 1.
2B
2D
A
A
A
A
M
G
G
G
G
C
C
C
R
C
Type 4
Type 2
Type 3
Type 1
Section X-X
IEC  1475/05
Figure 1 – Dimensions of RM-cores
Table 1 – Dimensions of RM-cores
a)
A B C D E F G H J R
mm mm mm mm mm mm mm mm mm mm
Size Type
Min. Max. Min. Max. Min. Max. Min. Max. Min.
...

IEC 62317-4 ®
Edition 1.0 2005-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Ferrite cores – Dimensions –
Part 4: RM-cores and associated parts

Noyaux ferrites – Dimensions –
Partie 4: Noyaux RM et pièces associées

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 la CEI ou du Comité national de la CEI du pays du demandeur.

Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette

publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: [e-mail]
Web: www.iec.ch
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 corrigenda or an amendment might have been published.
 Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
 IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
 Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
 Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: [e-mail]
Tel.: [phone]
Fax: [phone]
A propos de la CEI
La Commission Electrotechnique Internationale (CEI) 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 CEI
Le contenu technique des publications de la CEI est constamment revu. Veuillez vous assurer que vous possédez
l’édition la plus récente, un corrigendum ou amendement peut avoir été publié.
 Catalogue des publications de la CEI: www.iec.ch/searchpub/cur_fut-f.htm
Le Catalogue en-ligne de la CEI vous permet d’effectuer des recherches en utilisant différents critères (numéro de référence,
texte, comité d’études,…). Il donne aussi des informations sur les projets et les publications retirées ou remplacées.
 Just Published CEI: www.iec.ch/online_news/justpub
Restez informé sur les nouvelles publications de la CEI. Just Published détaille deux fois par mois les nouvelles
publications parues. Disponible en-ligne et aussi par email.
 Electropedia: www.electropedia.org
Le premier dictionnaire en ligne au monde de termes électroniques et électriques. Il contient plus de 20 000 termes et
définitions en anglais et en français, ainsi que les termes équivalents dans les langues additionnelles. Egalement appelé
Vocabulaire Electrotechnique International en ligne.
 Service Clients: www.iec.ch/webstore/custserv/custserv_entry-f.htm
Si vous désirez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du
Service clients ou contactez-nous:
Email: [e-mail]
Tél.: [phone]
Fax: [phone]
IEC 62317-4 ®
Edition 1.0 2005-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Ferrite cores – Dimensions –
Part 4: RM-cores and associated parts

Noyaux ferrites – Dimensions –
Partie 4: Noyaux RM et pièces associées

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX S
ICS 29.100.10 ISBN 978-2-88912-594-4

– 2 – 62317-4  IEC:2005
CONTENTS
FOREWORD . 3

1 Scope . 5

2 Normative references. 5

3 Primary standards . 5

3.1 Pin locations and base outlines . 5

3.2 Dimensions of RM-cores . 5

3.3 Shape of coil former and pin numbering . 6

3.4 Effective parameter values . 6
3.5 Spring recess . 6
3.6 Stud recess . 6
4 Derived standards . 10
5 Main dimensions for coil formers . 13
5.1 RM-cores for primary standard . 13
5.2 RM-cores intended particularly for power applications . 15
Annex A (informative) RM-core design . 18
Annex B (normative) Guidance for measuring clamping forces relevant to RM-core tests . 20
Bibliography . 22

Figure 1 – Dimensions of RM-cores . 7
Figure 2 – Dimensions of low-profile RM-cores . 8
Figure 3 – Dimensions of spring recess . 11
Figure 4 – Dimensions of stud recess . 12
Figure 5 – Main dimensions of coil formers for RM-cores . 13
Figure 6 – Pin locations and base outlines viewed from the underside of the board . 14
Figure 7 – Dimensions of specific features . 16
Figure 8 – Pin locations and base outlines viewed from the underside of the board . 17
Figure B.1 – Mounting device . 20

Table 1 – Dimensions of RM-cores . 7
Table 2 – Dimensions of low-profile RM-cores . 8

Table 3 – Effective parameter and A values for RM-cores . 9
min
Table 4 – Effective parameter and A values for low-profile RM-cores . 9
min
Table 5 – Spring recess . 11
Table 6 – Stud recess . 12
Table 7 – Main dimensions of coil formers for RM-cores . 13
Table 8 – Main dimensions of coil formers for low-profile RM-cores . 13
Table 9 – Dimensions of specific features. 16
Table B.1 – Inner diameters and recommended clamping forces . 21

62317-4  IEC:2005 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

___________
FERRITE CORES – DIMENSIONS –
Part 4: RM-cores and associated parts

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 62317-4 has been prepared IEC technical committee 51: Magnetic
components and ferrite materials.

This international standard cancels and replaces the second edition of IEC 60431 published in
1983, its amendment 1 (1995), and its amendment 2 (1996). This international standard
constitutes a technical revision of IEC 60431.
This bilingual version (2011-07) replaces the English version.
The main changes with respect to the previous edition of IEC 60431 are listed below:
– low-profile RM-cores at present defined in IEC 61860 are added to this standard.
IEC 61860 will eventually be replaced by IEC 62317-9 which is under consideration. IEC 62317-9
will not include the low-profile RM-cores.

– 4 – 62317-4  IEC:2005
The text of this standard is based on the following documents:

FDIS Report on voting
51/833/FDIS 51/839/RVD
Full information on the voting for the approval of this standard can be found in the report on voting

indicated in the above table.
The French version of this standard has not been voted upon.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
IEC 62317 consists of the following parts, under the general title Ferrite cores – Dimensions:
Part 1: General (under consideration)
Part 2: Pot cores (under consideration, currently available as IEC 60133)
Part 3: Half pot cores (under consideration, currently available as IEC 62323)
Part 4: RM-cores and associated parts
Part 5: EP-cores (under c
...