Cores made of soft magnetic materials - Measuring methods -- Part 2: Magnetic properties at low excitation level

Gives guidance for the drafting of those parts of specifications for magnetic cores that are concerned with measuring methods for magnetic and electric core properties. Applies to magnetic cores, mainly made of magnetic oxides or metallic powders, used at low excitation level in inductors and transformers for telecommunication equipment and electronic devices employing similar techniques.

Kerne aus weichmagnetischen Materialien - Messverfahren -- Teil 2: Messungen der magnetischen Eigenschaften im Signalapplikationsbereich

Noyaux en matériaux magnétiques doux - Méthodes de mesure -- Partie 2: Propriétés magnétiques à niveau d'excitation faible

Donne des lignes directrices pour la rédaction des parties des spécifications pour les noyaux magnétiques qui concernent les méthodes de mesure pour les propriétés magnétiques et électriques. S'applique aux noyaux magnétiques, principalement en oxydes magnétiques ou en poudres métalliques, utilisés à faible niveau d'excitation dans des inductances et transformateurs pour le matériel de télécommunications et les dispositifs électroniques utilisant des techniques analogues.

Jedra iz mehkomagnetnih materialov – Merilne metode – 2. del: Magnetne lastnosti pri šibkem vzbujanju (IEC 62044-2:2005)

General Information

Status
Published
Publication Date
30-Nov-2005
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Dec-2005
Due Date
01-Dec-2005
Completion Date
01-Dec-2005

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SLOVENSKI SIST EN 62044-2:2005
STANDARD
december 2005
Jedra iz mehkomagnetnih materialov – Merilne metode – 2. del: Magnetne
lastnosti pri šibkem vzbujanju (IEC 62044-2:2005)
Cores made of soft magnetic materials – Measuring methods – Part 2: Magnetic
properties at low excitation level (IEC 62044-2:2005)
ICS 29.100.10 Referenčna številka
SIST EN 62044-2:2005(en)

© Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

---------------------- Page: 1 ----------------------
EUROPEAN STANDARD EN 62044-2
NORME EUROPÉENNE
EUROPÄISCHE NORM April 2005
ICS 29.100.10
English version
Cores made of soft magnetic materials –
Measuring methods
Part 2: Magnetic properties at low excitation level
(IEC 62044-2:2005)

Noyaux en matériaux magnétiques doux - Kerne aus weichmagnetischen Materialien -

Méthodes de mesure Messverfahren
Partie 2: Propriétés magnétiques à niveau Teil 2: Messungen der magnetischen
d'excitation faible Eigenschaften im Signalapplikationsbereich
(CEI 62044-2:2005) (IEC 62044-2:2005)

This European Standard was approved by CENELEC on 2005-04-01. CENELEC members are bound to

comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European

Standard 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 Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, 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 Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech

Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,

Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2005 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 62044-2:2005 E
---------------------- Page: 2 ----------------------
EN 62044-2:2005 - 2 -
Foreword

The text of document 51/804/FDIS, future edition 1 of IEC 62044-2, prepared by IEC TC 51, Magnetic

components and ferrite materials, was submitted to the IEC-CENELEC parallel vote and was

approved by CENELEC as EN 62044-2 on 2005-04-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2006-01-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2008-04-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice

The text of the International Standard IEC 62044-2:2005 was approved by CENELEC as a European

Standard without any modification.
__________
---------------------- Page: 3 ----------------------
- 3 - EN 62044-2:2005
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE Where an international publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.
Publication Year Title EN/HD Year
1) 2)
IEC 60205 - Calculation of the effective parameters of EN 60205 2001
magnetic piece parts
IEC 60401-3 2003 Terms and nomenclature for cores made EN 60401-3 2003
of magnetically soft ferrites
Part 3: Guidelines on the format of data
appearing in manufacturers' catalogues of
transformer and inductor cores
IEC 62044-1 2002 Cores made of soft magnetic materials - EN 62044-1 2002
Measuring methods
Part 1: Generic specification
Undated reference.
Valid edition at date of issue.
---------------------- Page: 4 ----------------------
NORME CEI
INTERNATIONALE IEC
62044-2
INTERNATIONAL
Première édition
STANDARD
First edition
2005-03
Noyaux en matériaux magnétiques doux –
Méthodes de mesure –
Partie 2:
Propriétés magnétiques à niveau
d'excitation faible
Cores made of soft magnetic materials –
Measuring methods –
Part 2:
Magnetic properties at low excitation level
 IEC 2005 Droits de reproduction réservés  Copyright - all rights reserved

Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any

utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including

électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from

microfilms, sans l'accord écrit de l'éditeur. the publisher.

International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland

Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch

CODE PRIX
Commission Electrotechnique Internationale PRICE CODE V
International Electrotechnical Commission
Международная Электротехническая Комиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue
---------------------- Page: 5 ----------------------
62044-2  IEC:2005 – 3 –
CONTENTS

FOREWORD.........................................................................................................................7

1 Scope and object..........................................................................................................11

2 Normative references ...................................................................................................11

3 Definitions ....................................................................................................................11

4 Symbols .......................................................................................................................13

5 Environmental conditions..............................................................................................17

6 General precautions for methods involving permeability measurements .........................17

6.1 Parameters involved ............................................................................................17

6.2 Mounting of cores consisting of more than one part ..............................................17

7 General precautions for loss measurement at low flux density .......................................17

7.1 Contributory losses..............................................................................................17

7.2 Mounting .............................................................................................................19

8 Magnetic conditioning ...................................................................................................19

9 Inductance measurement..............................................................................................21

9.1 General ...............................................................................................................21

9.2 Determination of the test signal............................................................................21

9.3 Determination of the test coil ...............................................................................23

9.4 Considerations for core alignment during test.......................................................27

9.5 Measurement of inductance under the influence of d.c. magnetic field ..................29

9.6 Parameters related to core geometry ...................................................................31

9.7 Magnetic material parameters ..............................................................................33

10 Disaccommodation .......................................................................................................37

11 Temperature coefficient of permeability.........................................................................37

11.1 Specimens ..........................................................................................................37

11.2 Measuring procedure ...........................................................................................39

12 Losses at low flux density .............................................................................................41

12.1 Object .................................................................................................................41

12.2 Measuring coil .....................................................................................................41

12.3 Measurement of residual and eddy current loss....................................................41

12.4 Measurement of the hysteresis loss .....................................................................43

13 Total harmonic distortion ..............................................................................................45

13.1 Specimen ............................................................................................................45

13.2 Measuring instrument and circuit..........................................................................45

13.3 Measuring procedure ...........................................................................................45

13.4 A value and winding conditions for THD measurement.......................................47

L F

13.5 Material characteristics – THD ............................................................................47

14 Curie temperature.........................................................................................................49

15 Normalized impedance, parallel conductivity, and insertion loss.....................................49

15.1 General ...............................................................................................................49

15.2 Measuring procedure ...........................................................................................49

15.3 Normalized impedance ........................................................................................51

15.4 Parallel conductivity.............................................................................................51

---------------------- Page: 6 ----------------------
62044-2  IEC:2005 – 5 –

Annex A (informative) Disaccommodation...........................................................................53

Annex B (informative) Measurement conditions for THD testing ..........................................57

Figure 1 – Pictorial representation of the effect of self-resonant frequency on the

value of measured inductance.............................................................................................23

Figure 2 – THD measuring circuit ......................................................................................45

Figure 3 – Curie temperature ..............................................................................................49

Figure B.1 – Flux density as a function of number of turns ...................................................57

Figure B.2 – Circuit correction factor (CCF) as a function of number of turns........................61

Table 1 – Relationship of test turns to magnetic structure, test frequency and

inductance factor A ...........................................................................................................25

Table 2 – Specimen of A value and winding conditions for THD measurement ..................47

L F
---------------------- Page: 7 ----------------------
62044-2  IEC:2005 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CORES MADE OF SOFT MAGNETIC MATERIALS –
MEASURING METHODS –
Part 2: Magnetic properties at low excitation level
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 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 62044-2 has been prepared by IEC technical committee 51:

Magnetic components and ferrite materials.
The text of this standard is based on the following documents:
FDIS Report on voting
51/804/FDIS 51/816/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.
---------------------- Page: 8 ----------------------
62044-2  IEC:2005 – 9 –

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

IEC 62044 consists of the following parts, under the general title Cores made of soft magnetic

materials – Measuring methods:
Part 1: Generic specification
Part 2: Magnetic properties at low excitation level
Part 3: Magnetic properties at high excitation level

This standard, together with IEC 62044-1 (2002) and IEC 62044-3 (2000), cancels and

replaces IEC 60367-1 (1982), its amendment 1 (1984), its amendment 2 (1992), IEC 60367-2

(1974), its amendment 1 (1983) and IEC 60367-2A (1976).

The committee has decided that the contents of this publication will remain unchanged until

the maintenance result 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.
---------------------- Page: 9 ----------------------
62044-2  IEC:2005 – 11 –
CORES MADE OF SOFT MAGNETIC MATERIALS –
MEASURING METHODS –
Part 2: Magnetic properties at low excitation level
1 Scope and object

This part of IEC 62044 applies to magnetic cores, mainly made of magnetic oxides or metallic

powders, used at low excitation level in inductors and transformers for telecommunication

equipment and electronic devices employing similar techniques.

Some of the methods described in this part of IEC 62044 may also be suitable for magnetic

cores used in other components.

This part of IEC 62044 gives guidance for the drafting of those parts of specifications for

magnetic cores that are concerned with measuring methods for magnetic and electric core

properties. This part of IEC 62044 is limited to the general principles to be followed for

various possible test methods and sets out the factors to be taken into account when deciding

on the description of the test method to be included in the specification.

NOTE All the formulae in this part of IEC 62044 use basic SI units. When multiples or submultiples are used, the

appropriate power of 10 should be introduced. The conversion factor for inductances and inductance factors is as

follows: 1 H = 10 nH.
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 60205, Calculation of the effective parameters of magnetic piece parts

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

IEC 62044-1:2002, Cores made of soft magnetic materials – Measuring methods – Part 1:

Generic specification
3 Terms and definitions

For the purposes of this part of IEC 62044, the following terms and definitions apply.

---------------------- Page: 10 ----------------------
62044-2  IEC:2005 – 13 –
3.1
(magnetic) Total Harmonic Distortion
THD

distortion of voltage waveform caused by non-linear relation between the magnetic flux

density and the magnetic field strength in a ferrite core and expressed by:
THD = 20lg(V /V) (1)
m f
where
V = V (2)
m ∑ n
n=1

V is the amplitude of the n harmonic component of the quantity and V is the amplitude of

n f
the fundamental component of the quantity
3.2
(magnetic) Total Harmonic Distortion Factor
THD

mathematical expression used for the evaluation of characteristics of magnetic materials and

given by:
 
V /V
m f
 
THD = 20lg (3)
 
µ / CCF
 ea 
where
V = V (4)
m ∑ n
n=1

V is the amplitude of the n harmonic component of the quantity and V is the amplitude of

n f
the fundamental component of the quantity
CCF = 1/ 1+()3ωL / R (5)
1 s

NOTE 1 CCF stands for the Circuit Correction Factor and is given in the approximation for the third harmonic,

which is valid for measurements without applied d.c. bias. L is primary inductance. R is total source resistance

1 s
(50 Ω).
NOTE 2 µ is the effective amplitude permeability.
4 Symbols
The following standard symbols are used in this standard.
t time
T temperature in °C
T curie temperature
L self-inductance
L self-inductance at temperature
L inductance seen at low a.c. excitation
measured
Z impedance seen at low a.c. excitation
measured
---------------------- Page: 11 ----------------------
62044-2  IEC:2005 – 15 –
R imaginary part of impedance seen at low a.c. excitation
measured
µ magnetic constant: 0,4 π × 10 H/m
µ complex relative permeability (measured in series inductance mode)
µ initial permeability
µ effective permeability
µ same as µ
r,s r
µ complex relative permeability (measured in parallel inductance mode)
r,p

µ′ real part of complex relative permeability (measured in series inductance mode)

µ′ same as µ′
r,s r
µ′ real part of complex relative permeability (measured in parallel inductance
r,p
mode)

µ″ imaginary part of complex relative permeability (measured in series inductance

mode)
µ″ same as µ″
r,s r
µ″ imaginary part of complex relative permeability (measured in parallel
r,p
inductance mode)
µ initial permeability at temperature
µ effective amplitude permeability
N number of turns of measuring coil
C core constant defined in IEC 60205
A effective cross-sectional area
l effective magnetic path length
ω angular frequency
f frequency
f lower end of frequency band
U r.m.s. value of sinusoidal voltage
V voltage amplitude of the square root of the quadratic sum of the amplitudes
over all harmonics
V voltage amplitude at the fundamental frequency
THD (magnetic) total harmonic distortion
THD (magnetic) total harmonic distortion factor
CCF circuit correction factor (for THD calculation)
B peak flux density: same as a.c. flux density
A inductance factor
l effective air-gap length
A effective gap area
α temperature coefficient of permeability
α temperature factor
---------------------- Page: 12 ----------------------
62044-2  IEC:2005 – 17 –
tan δ tangent loss angle
tan δ tangent loss angle for gapped core
(tan δ/µ) hysteresis loss factor
η hysteresis material constant
Z (f) normalized impedance
g (f) parallel conductivity
R (f) parallel resistance
a (f) insertion loss due to core contribution
D disaccommodation
D disaccommodation factor
5 Environmental conditions
The environmental conditions shall comply with Clause 3 of IEC 62044-1.
6 General precautions for methods involving permeability measurements
6.1 Parameters involved

The effective permeability of a core depends upon many factors, among which are the

magnetic history, time, temperature, field strength, mechanical pressure, frequency of

measuring current, core geometry and position of the measuring coil. Various methods

described in this standard single out one of these factors at a time, for example, time or

temperature, and precautions during these measurements should be directed towards

eliminating the influence of all other factors. For example, a clamping device should be such

that the pressure remains constant in time and with temperature, so that the measuring result

is not influenced by changing pressure.
6.2 Mounting of cores consisting of more than one part
The mounting of cores shall be in accordance with IEC 62044-1.
7 General precautions for loss measurement at low flux density
7.1 Contributory losses

At low flux density (i.e. within the Rayleigh region), the loss measured on a core by means of

a coil or other coupling device is due to a number of causes; some may be inherent in the

core itself, some in the coupling device and some in the connection between the coupling

device and the measuring instrument. For measurements with coils, the following contributory

losses can be distinguished: core loss; d.c. coil loss; Iosses due to skin effect and proximity

effect; dielectric loss in the coil; Ioss in connecting wires and loss in any associated

component (for example, resonating capacitor).

An attempt should be made to isolate the core loss from the total loss measured, either by

correction or by choosing the conditions so as to make the other contributory losses negligible.

The d.c. coil loss and the loss in any associated component can be measured separately; the

other contributory losses may be either calculated or determined experimentally.
---------------------- Page: 13 ----------------------
62044-2  IEC:2005 – 19 –

The determination of the core loss does not present undue difficulties for ferrite cores without

an air-gap or with a very small air-gap (for example, toroids and shaped cores without

intentional air-gap) because, with a suitably designed coil, the core loss is then appreciably

higher than any other of the contributory losses.

This may not be the case for loss measurement on gapped cores for which it may be difficult

to obtain a sufficiently accurate result for the core loss alone.
Two methods may then be followed.

a) Measure the loss factor with gapless core and calculate the loss in the gapped core.

NOTE It is not permissible to measure the loss factor on an ungapped core having a geometry different from

that of the gapped core, for example, on a toroid of the same material, since the eddy-current core loss

strongly depends upon the core geometry. However, the measurement on cores with a centre-hole wound as a

toroid is acceptable.

b) Make no attempt to separate core and coil losses but compare the combined loss of the

core and the measuring coil with the results obtained from similar measurements on other

cores using a coil of identical construction and having the same d.c. resistance.

The best policy is to obtain these measuring coils from the same source or at least according

to the same specification, which should include the d.c. resistance value of the (empty) coil.

7.2 Mounting

Coupling between the stray field of the core and extraneous objects shall be avoided.

Connections between the measuring coil or other coupling device and the measuring

instrument shall be short, direct and so fixed that movement of the specimen cannot cause

additional error. It is also advisable to twist the connection leads to make electromagnetic

fields induced in adjacent parts partly counteract each other.

Cores of more than one part that assemble around the measuring coil shall in general be

clamped as specified in Clause 4 of IEC 62044-1.

NOTE 1 Regarding the clamping force for tan δ, η and THD measurement, it is recommended that the clamping

B F

force be kept equal to 0,2 N/mm , with a relative tolerance of ± 10 % and to apply the force only in a direction

perpendicular to the mating surface.

NOTE 2 Regarding the clamping force for A , α , D and Z measurement, it is recommended that the clamping

L F F N
2 2

force be maintained in the range 0,6 N/mm through 1,0 N/mm for cores for which the effective cross-sectional

area (A ) is less than 50 mm and at 50 N, with a relative tolerance of ±10 %, for cores with an effective cross-

sectional area (A ) greater than 50 mm .
The positioning of the measuring coil on the core shall be as described in 9.3.
8 Magnetic conditioning

To arrive at a well-defined and reproducible magnetic state of a core before the measure-

ments, magnetic conditioning shall be carried out in accordance with Clause 5 of IEC 62044-1.

---------------------- Page: 14 ----------------------
62044-2  IEC:2005 – 21 –
9 Inductance measurement
9.1 General

Clause 9 provides general instructions for the measurement of inductance of inductor and

transformer windings, without going into details of the method, which depends upon the

electrical instrument used for the measurement.
Three measurement purposes should be distinguished:
a) to obtain the absolute value of the inductance parameter of the core;
b) to obtain the dependence of the inductance value under certain conditions;

c) to apply results of measurements in equations determining the magnetic permeability of

the core material for specific conditions.
9.2 Determination of the test signal

AC magnetic property analysers are used to make inductance measurements. The capability

of the equipment shall be such that it can provide a sinusoidal a.c. signal with a selectable

frequency and either a selectable voltage or selectable current. The test signal provided by

this equipment has limitations for the magnitude of the voltage and the current. The upper

limit for a.c. voltage for this type of equipment is typically between 1 V and 20 V .

r.m.s. r.m.s.

The a.c. current limit for this type of equipment is typically 0,010 A and 0,020 A .

r.m.s. r.m.s.

Measurements are made using the series mode unless the parallel mode is specified.

The accuracy of the recommended measurement equipment varies as a function of

impedance or inductance level at different frequencies. An impedance level in the range 50 Ω

to 1 000 Ω is typically required to obtain the required levels of voltage and current. The

desired accuracy of the test equipment shall be verified for specific impedance levels at

different frequencies.

The frequency of the measuring current and the peak flux density shall be stated.

NOTE The peak flux density in a core, B, also called the a.c. flux density, is calculated from:

B = (6)
2π × f × N × A
where
B is expressed in Tesla (T);
U is the r.m
...

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