IEC 60401-3:2015

Terms and nomenclature for cores made of magnetically soft ferrites - Part 3: Guidelines on the format of data appearing in manufacturers catalogues of transformer and inductor cores

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.

Termes et nomenclature pour noyaux en matériaux ferrites magnétiquement doux - Partie 3: Lignes directrices relatives aux formats des données figurant dans les catalogues des fabricants de noyaux pour transformateurs et inductances

L'IEC 60401-3:2015 sert de lignes directrices pour une méthode de présentation uniforme des propriétés des matériaux ferrites magnétiquement doux et des conditions de mesure à partir desquelles il convient de les déterminer. Elle est destinée à être utilisée pour les catalogues des fabricants de noyaux pour transformateurs et inductances afin de faciliter la comparaison de telles données. Un guide supplémentaire portant sur les essais et la spécification de la fiabilité pour les noyaux ferrites et pour les dispositifs utilisant des noyaux ferrites existe pour les utilisateurs et les fabricants. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- ajout de l'Article 6 sur la fiabilité.

General Information

• Status: Published
• Publication Date: 03-Dec-2015
• 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: PPUB - Publication issued
• Start Date: 04-Dec-2015
• Completion Date: 31-Dec-2015

Relations

• Revises: IEC 60401-3:2003 - Terms and nomenclature for cores made of magnetically soft ferrites - Part 3: Guidelines on the format of data appearing in manufacturers' catalogues of transformer and inductor cores
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60401-3 ®
Edition 2.0 2015-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Terms and nomenclature for cores made of magnetically soft ferrites –
Part 3: Guidelines on the format of data appearing in manufacturers catalogues
of transformer and inductor cores

Termes et nomenclature pour noyaux en matériaux ferrites magnétiquement
doux –
Partie 3: Lignes directrices relatives aux formats des données figurant dans les
catalogues des fabricants de noyaux pour transformateurs et inductances

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IEC 60401-3 ®
Edition 2.0 2015-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Terms and nomenclature for cores made of magnetically soft ferrites –

Part 3: Guidelines on the format of data appearing in manufacturers catalogues

of transformer and inductor cores

Termes et nomenclature pour noyaux en matériaux ferrites magnétiquement

doux –
Partie 3: Lignes directrices relatives aux formats des données figurant dans les

catalogues des fabricants de noyaux pour transformateurs et inductances

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.100.10 ISBN 978-2-8322-3029-9

– 2 – IEC 60401-3:2015 © IEC 2015
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Measuring methods . 6
4 Table of material properties and measuring conditions . 6
5 Integrity of value . 7
6 Reliability . 9
Annex A (informative) Breakdown voltage test for insulated ring cores – Measurement
techniques . 11
A.1 Method A . 11
A.2 Method B . 11
A.2.1 General. 11
A.2.2 Method B 1 . 11
A.2.3 Method B 2 . 12
A.2.4 Method B 3 . 12
A.3 Notes on voltage breakdown testing . 13
Bibliography . 14

Figure A.1 – Method A: measurement principle . 11
Figure A.2 – Method B 1: Measurement principle . 12
Figure A.3 – Method B 2: Measurement principle . 12
Figure A.4 – Method B 3: Measurement principle . 13

Table 1 – Rules for property values given in Table 2 . 7
Table 2 – Property values and measuring conditions (1 of 2) . 8

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TERMS AND NOMENCLATURE FOR CORES MADE
OF MAGNETICALLY SOFT FERRITES –

Part 3: Guidelines on the format of data appearing in manufacturers
catalogues of transformer and inductor 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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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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 60401-3 has been prepared IEC technical committee 51: Magnetic
components and ferrite materials.
This second edition cancels and replaces the first edition published in 2003. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) addition of reliability in Clause 6.

– 4 – IEC 60401-3:2015 © IEC 2015
The text of this standard is based on the following documents:
FDIS Report on voting
51/1106/FDIS 51/1121/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.
A list of all parts in the IEC 60401 series, published under the general title Terms and
nomenclature for cores made of magnetically soft ferrites, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website 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.
INTRODUCTION
For various reasons, a manufacturer may wish to publish in its catalogue typical data for
material parameters as measured on test pieces. It is the object of this part of IEC 60401 to
promote the comparability of such information in the area of soft ferrite materials.
Except for several specific property limits that should be given separately for each particular
core, the properties described in this standard are material characteristics, intended to
facilitate meaningful evaluation of ferrite materials. It should be recognized, however, that
there is no direct relation between material characteristics as measured on test pieces and
the corresponding parameters measured on other cores, made of the same material, because
of differences in geometry and variation in production processes. Also, the extrapolation of
material characteristics to other flux densities and other frequencies will not permit valid
comparison of cores of different materials under these new conditions of operation.
It is therefore emphasized that it is impossible to design and specify a core on the basis of
material properties published by a manufacturer in its catalogue, without due contact with that
manufacturer. Also, the publication of material characteristics should not be considered as a
guarantee for core properties; for this purpose, only the specification of that core should be
used.
It is strongly recommended that, together with the material characteristics, manufacturers
publish a note covering the two statements above on the limitations of this kind of information.
This standard further addresses the comparability of various grades of ferrite from different
manufacturers by defining the baseline reliability and temperature performance that is
inherent for all MnZn ferrite materials, and the limitations that exist when specifying related
performance characteristics in ferrite cores.

– 6 – IEC 60401-3:2015 © IEC 2015
TERMS AND NOMENCLATURE FOR CORES MADE
OF MAGNETICALLY SOFT FERRITES –

Part 3: Guidelines on the format of data appearing in manufacturers
catalogues of transformer and inductor cores

1 Scope
This part of IEC 60401 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.
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 edition of the referenced document (including any
amendments) applies.
IEC 61332:2005, Soft ferrite material classification
IEC 62044-2, Cores made of soft magnetic materials – Measuring methods – Part 2: Magnetic
properties at low excitation level
IEC 62044-3, Cores made of soft magnetic materials – Measuring methods – Part 3: Magnetic
properties at high excitation level
3 Measuring methods
The measuring methods should conform to the general procedures and precautions given in
IEC 62044-1, IEC 62044-2 and IEC 62044-3. The test piece for the magnetic measurements
should be a ring-core, preferably one of the sizes R10 to R36 in accordance with
2 2
IEC TR 61604, and having corresponding A values within the range 8 mm to 100 mm .
e
Table 2 indicates recommended test conditions.
4 Table of material properties and measuring conditions
The conditions laid down in Table 2 have been chosen as representative of those that are in
common use. This means that in the majority of cases the values now published by
manufacturers will differ only slightly from the corresponding values at the measuring
conditions given in Table 2. It is therefore expected that only small adjustments to existing
catalogues will be required.
The following rules are recommended for the use of Table 2 by manufacturers:
a) properties not of importance for the application of the material in question should be
omitted;
b) where for one property several measuring conditions are stated with one or more
underlined, the conditions underlined shall be used and the rest are optional;

c) if none of the measuring conditions is underlined, the choice is free and at least one shall
be used;
d) values obtained under measuring conditions deviating from those specified in the table
may be added to those required according to items b) and c) above.
5 Integrity of value
The following rules shown in Table 1 shall be applied for the property values given in Table 2.
It is recommended to describe whether each value in a manufacturer’s document is a “typical
value” or a “limit value” for better understanding.
Table 1 – Rules for property values given in Table 2
Type of document Typical value Limit value
a
Table of material properties THD , Z , P µ , B , (tanδ)/µ ,η , T ,α , D

F N V i s i B c F F
Property graph All properties
Table of (shaped) core properties A , THD , Z , P

L F N V
a
Any other values in a table of material properties not specified here are to be given as “typical value”.

– 8 – IEC 60401-3:2015 © IEC 2015
Table 2 – Property values and measuring conditions (1 of 2)
Property -  Measuring conditions
valid for test ring
Peak
cores only sizes
Temperature Footn
Symbol Unit Frequency Field strength flux
R10 to R36
(see Clause 4) otes
density
(see Clause 3)
kHz kA/m mT °C
Initial permeability µ  25
≤ 10 < 0,50
i
Saturation 1,2 (µ > 1 000)
I
k
magnetic flux B mT 25; 100
≤ 10
s
3 (1 000 ≥ µ>500 )
density i
10 (500 ≥ µ >100 )
Remanent flux i
B
mT 25; 100 a
r ≤ 10
density
20 (100 ≥ µ )
i
Coercivity H A/m 25; 100 a
c ≤ 10
Losses at low flux
tanδ/µ  25 b
< 0,25
i
density
B B
1    2
1,5
(µ ≥ 500)
I
Hysteresis
−1
T 3,0 25 c
η
B
material constant
100 0,3
(µ < 500) 1,2
I
T
Curie temperature °C  d
c ≤ 10 < 0,25
−40
between −25
-
Relative 10
α 6 25 and +5 e
≤ 10 < 0,25
F
temperature factor /°C
+55
+85
kg/
(Mass) density d
b
m
Disaccommodation
−6
D 10 25; 40 d
≤ 10 < 0,25
F
factor
l
Resistivity DC 25 f
ρ Ωm
Total harmonic
THD dB 5 50 25 g
F
distortion factor
Normalized
Z
Ω/m 25 d
< 0,25
N
impedance
The following properties are only valid for materials used for power applications
25 200 100;
100 200 Minimum loss
temperature
100 100
200 100
P kW/ 300 100 h
v
Power loss
m
(volume) density
500 50
1 000 50
2 000 20
5 000 10
50 150 25; 100 i
Table 2 (2 of 2)
Property -  Measuring conditions
valid for test ring
Peak
cores only sizes
Temperature Footn
Symbol Unit Frequency Field strength flux
R10 to R36
(see Clause 4) otes
density
(see Clause 3)
kHz kA/m mT °C
400 25
Amplitude
µ ≤ 25 j
a
permeability
320 100
a Information should be given about the measuring method, especially the frequency.
b Measurement shall be made at a frequency chosen from Table 1 and Table 2 of IEC 61332:2005
µ .The losses at low flux density may be given in a graph as a function of frequency. Low-
corresponding to
i
Ievel losses comprise both the eddy current and the residual losses but the former can be made insignificant
as compared to the latter, see Clause 3.
c η shall be based on measurement at two flux densities B and B , such that B ≤ B /2.

B 1 2 1 2
d The measuring method shall be in accordance with IEC 62044-2.
µ −µ 1
e . The measuring method shall be in accordance with IEC 62044-2.
T ref
α = ×
F
T−T
µ
ref
ref
f The firing skin shall be removed from the test piece. The electric field strength shall not exceed 0,1 kV/m.
 V / V  1
g m 1 where
THD = 20lg  CCF=
F
 
µ / CCF
 ea 
1+(3ωL / R)
p s
The measuring method and core size shall be in accordance with IEC 62044-2. This property is applied only
for a specific application such as XDSL.
h The effective volume V according to IEC 62044-3 shall be used to determine the volume-related power loss
e
P . For determination of the volume related power loss P , the voltage for the required flux density shall be
v v
calculated in accordance with IEC 62044-3. The power losses may be shown in a series of graphs as
functions of flux density with the frequency as a parameter of individual graphs. Where specific values of
power loss are quoted, these shall correspond to the preferred combinations of frequency and flux density
shown in Table 2.
i This condition shall be applied for the core to be used for a back-light.
j For determination of the amplitude permeability, the measuring method shall be in accordance with
IEC 62044-3.
k Both temperatures are to be used for material for power applications: for other applications the higher
temperature is optional.
l
Formerly referred to as "specific resistance”.

6 Reliability
Reliability as it relates to ferrite cores is different from reliability for inductors or transformers,
because cores are necessarily incorporated mechanically into the structures of inductors or
transformers. It is those structures that see application conditions, and exhibit endurance or
lack of endurance in use. IEC 62211 is the IEC guide for magnetics reliability. It addresses
wound devices, not cores in isolation.
Guidelines for data to be shown in manufacturers’ catalogues for ferrite cores do not include
reliability testing or specification limits, and in practice reliability claims are not made in
manufacturers’ catalogues.
It is important for users of ferrites to be aware of some general facts about inherent ferrite
material properties:
– 10 – IEC 60401-3:2015 © IEC 2015
a) Ferrites are dense ceramics, not alloys, and not heterogeneous structures. They are
inherently very chemically stable.
b) Curie temperature and maximum rated temperature for ferrites are not the same. Ferrites
can be safely exposed to temperatures far higher than Curie temperature, so long as the
temperature change is not too rapid, and the ferrite is not required to perform magnetically
while above the Curie temperature.
c) Temperature effects in ferrites are reversible, which means that a core will return to the
same magnetic performance at the same temperature no matter what other temperatures
it is exposed to in the meantime. This is generally true up to the limit of a temperature far
above Curie, where the material becomes reactive. But it is not true if the change in
temperature is rapid enough to cause thermal shock cracks.
d) Reliability testing, such as is required for many automotive components, or such as for
inductive components in IEC 62211, is not relevant for ferrites alone. It is the performance
of assembled inductive devices – including ferrite, wire, terminations, potting, coil formers,
mounting fixtures, etc. – that is logical to assess for reliability.
e) Chips and small cracks are not special reliability hazards for ferrites. Chip and crack sizes
are controlled for cosmetic and workmanship reasons, and are subject to standard limits
in the IEC 60424 series.
f) Mechanical strength generally is considered to be adequate and repeatable by handling
during manufacture. It is also documented in some case by break strength testing. See
IEC 61631.
g) Manufacturers generally qualify ring core coatings for adequate adhesion, temperature
stability, and solvent resistance. For each different coating, a maximum continuous
operating temperature limit applies. Standard practice is to conduct voltage breakdown
testing for each batch of coated parts. See Annex A.
h) Different winding wires and different winding techniques result in varying degrees of
mechanical impact or stress delivered to the coating. Manufacturers are unable to
guarantee that coatings will remain undamaged regardless of the impact or stress applied
from winding. It is not uncommon for winding impact to cause coating chips on normally
coated ring cores.
i) Mechanical stresses from winding, potting, or encapsulation can degrade electrical
performance. Such stress effects are reversible, as long as cracks are not created. It is
generally not possible for the manufacturer to significantly alter or control the
susceptibility of ferrite cores to shifts due to mechanical stress. It is an inherent property
of ferrites. Higher permeability materials tend to be more sensitive. Different grades of
material exhibit different characteristic sensitivity.

Annex A
(informative)
Breakdown voltage test for insulated ring cores –
Measurement techniques
A.1 Method A
This procedure may be used for testing ring cores having inner diameters larger than 6 mm.
Figure A.1 shows the principle of a typical measurement. The ring core to be tested is wound
by at least two single turns whose leads are short-circuited and are positioned 180° apart.
Both windings should be wound tight around the core cross section in order to ensure a
maximum mechanical contact. The wires consist of bare copper, for example 100 wires of
0,06 mm. The two ends of the windings are connected to the output of a generator providing
the necessary test voltage (DC or AC).
This test method only ensures that the specified voltage is reached at the winding positions. It
is recommended for the cases where the uniformity of insulation coating has been verified, or
is assumed.
Ring core
Copper braid
U
IEC
Key
U Test voltage (U : in case of DC and U : in case of AC).
DC eff
Figure A.1 – Method A: measurement principle
NOTE Figures A.1, A.2, A.3 and A.4 are schematic only, and the dimensions drawn are not to scale.
A.2 Method B
A.2.1 General
Three variations of method B are defined.
A.2.2 Method B 1
The measuring device consists of two outer ring-shaped shells (1) and two cylinders (2),
located in the centre of the specimen (3). It touches the ring core to be tested along the most
critical edges.
By this arrangement, the breakdown voltage test can be carried out either in the axial or in the
radial direction. Therefore, the voltage polarity of the generator has to be switched as
indicated on the drawing of Figure A.2.

– 12 – IEC 60401-3:2015 © IEC 2015
Sharp edges
should be
avoided
Ring core
IEC
Figure A.2 – Method B 1: Measurement principle
A.2.3 Method B 2
This version of method B is a simplified one. The device consists of two shells which contact
the specimen as indicated on the drawing of Figure A.3. This method is only usable in the
axial direction.
U
Ring core
IEC
Figure A.3 – Method B 2: Measurement principle
A.2.4 Method B 3
The test device consists of two metal disks covered with conductive rubber plates or copper
wire-mesh with rubber backing as indicated in Figure A.4. The specimen is placed between
the conductive rubber plates and a specified pressure is applied to the plates to ensure
contact with the edges of the specimen.
This method is applicable to test the breakdown voltage of medium and large ring cores in the
axial direction only.
Toroid
P
Conductive
rubber plates
P
IEC
Figure A.4 – Method B 3: Measurement principle
A.3 Notes on voltage breakdown testing
The methods shown above are effective for making repeatable measurements of the voltage
breakdown performance of ring core toroid coatings. The conductor arrangements are not the
same as application conductors, and therefore there is necessarily a correlation offset
between the voltage breakdown measured in the core test and the voltage breakdown
measured in finished wound inductive components.
Most prominently, ring cores are generally wound with insulated magnet wire, and the
insulation of the magnet wire significantly increases the potential isolation. The voltage
breakdown measured for a wound inductive device is not only a function of the ring core
coating, but of the magnet wire, windings, tapes and epoxies used.
Voltage breakdown can be a destructive test, in which case the sample size should be small,
but the resulting voltage values are specific
...