SIST EN 62044-3:2002
(Main)Cores made of soft magnetic materials - Measuring methods -- Part 3: Magnetic properties at high excitation level
Cores made of soft magnetic materials - Measuring methods -- Part 3: Magnetic properties at high excitation level
Provides measuring methods for power loss and amplitude permeability of magnetic cores forming the closed magnetic circuits intended for use at high excitation levels in inductors, chokes, transformers and similar devices for power electronics applications.
Kerne aus weichmagnetischen Materialien - Messverfahren -- Teil 3: Messungen der magnetischen Eigenschaften im Leistungsapplikationsbereich
Noyaux en matériaux magnétiques doux - Méthodes de mesure -- Partie 3: Propriétés magnétiques à niveau élevé d'excitation
Donne les méthodes de mesure de la perte de puissance et de la perméabilité d'amplitude des noyaux magnétiques formant les circuits magnétiques fermés destinés à être utilisés à des niveaux élevés d'excitation dans les bobines d'inductance, les bobines d'arrêt, les transformateurs et les dispositifs similaires pour les applications d'électronique de puissance.
Cores made of soft magnetic materials - Measuring methods - Part 3: Magnetic properties at high excitation level (IEC 62044-3:2000)
V tem standardu so predstavljene merilne metode za izgubo moči in amplitudno prepustnost magnetnih jeder, ki tvorijo zaprta magnetna vezja, namenjena za uporabo pri močnem vzbujanju v induktorjih, dušilkah, transformatorjih in podobnih napravah za aplikacije močnostne elektronike Metode, podane v tem standardu, lahko zajemajo merjenje magnetnih lastnosti za frekvence v območju od enosmernega toka do 10 MHz in morda še celo več, za kalorimetrične in odbojne metode. Uporabnost posameznih metod za določena frekvenčna območja je odvisna od stopnje natančnosti, ki jo je treba doseči.
Metode v tem standardu so v osnovi najprimernejše za sinusno vzbujanje. Uporabiti je mogoče tudi druge periodične valovne oblike, vendar zadostno natančnost je mogoče doseči le, če so uporabljena merilna vezja in instrumenti zmožni obravnavati ter obdelati amplitude in faze signalov, vključene v frekvenčnem spektru, ki ustreza danim valovnim oblikam indukcije in jakosti polja z le nekoliko manjšo natančnostjo.
OPOMBA: Za nekatere magnetno mehke kovinske materiale bo morda treba upoštevati posebna splošna načela v zvezi s pripravo primerkov in predpisanimi izračuni, ki so za takšne materiale običajna. Ta načela so navedena v standardu IEC 60404-8-6.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2002
Cores made of soft magnetic materials - Measuring methods - Part 3: Magnetic
properties at high excitation level (IEC 62044-3:2000)
Cores made of soft magnetic materials - Measuring methods -- Part 3: Magnetic
properties at high excitation level
Kerne aus weichmagnetischen Materialien - Messverfahren -- Teil 3: Messungen der
magnetischen Eigenschaften im Leistungsapplikationsbereich
Noyaux en matériaux magnétiques doux - Méthodes de mesure -- Partie 3: Propriétés
magnétiques à niveau élevé d'excitation
Ta slovenski standard je istoveten z: EN 62044-3:2001
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
29.100.10 Magnetne komponente Magnetic components
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN 62044-3
NORME EUROPÉENNE
EUROPÄISCHE NORM May 2001
ICS 29.030; 29.100.10
English version
Cores made of soft magnetic materials - Measuring methods
Part 3: Magnetic properties at high excitation level
(IEC 62044-3:2000)
Noyaux en matériaux magnétiques doux - Kerne aus weichmagnetischen
Méthodes de mesure Materialien - Messverfahren
Partie 3: Propriétés magnétiques à niveau Teil 3: Messungen der magnetischen
élevé d'excitation Eigenschaften im
(CEI 62044-3:2000) Leistungsapplikationsbereich
(IEC 62044-3:2000)
This European Standard was approved by CENELEC on 2001-03-01. 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, Czech Republic,
Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway,
Portugal, 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
© 2001 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62044-3:2001 E
Foreword
The text of document 51/573/FDIS, future edition 1 of IEC 62044-3, 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 62044-3 on 2001-03-01.
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) 2001-12-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2004-03-01
Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, annex ZA is normative and annexes A to E are informative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 62044-3:2000 was approved by CENELEC as a European
Standard without any modification.
__________
- 3 - EN 62044-3:2001
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
IEC 60050-221 1990 International electrotechnical vocabulary--
Chapter 221: Magnetic materials and
components
A1 1993 - -
A2 1999 - -
IEC 60205 1966 Calculation of the effective parameters--
of magnetic piece parts
IEC 60367-1 1982 Cores for inductors and transformers for--
telecommunications
Part 1: Measuring methods
IEC 60401 1993 Ferrite materials - Guide on the format--
of data appearing in manufacturers'
catalogues of transformer and inductor
cores
IEC 60404-8-6 1999 Magnetic materials --
Part 8-6: Specifications for individual
materials - Soft magnetic metallic
materials
IEC 61332 1995 Soft ferrite material classification EN 61332 1997
NORME
CEI
INTERNATIONALE IEC
62044-3
INTERNATIONAL
Première édition
STANDARD
First edition
2000-12
Noyaux en matériaux magnétiques doux –
Méthodes de mesure –
Partie 3:
Propriétés magnétiques à niveau élevé d'excitation
Cores made of soft magnetic materials –
Measuring methods –
Part 3:
Magnetic properties at high excitation level
© IEC 2000 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
utilisée sous quelque forme que ce soit et par aucun procédé, any form or by any means, electronic or mechanical,
électronique ou mécanique, y compris la photocopie et les including photocopying and microfilm, without permission in
microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: +41 22 919 0300 e-mail: inmail@iec.ch IEC web site http://www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale
V
PRICE CODE
International Electrotechnical Commission
Pour prix, voir catalogue en vigueur
For price, see current catalogue
62044-3 © IEC:2000 – 3 –
CONTENTS
Page
FOREWORD . 5
Clause
1 Scope . 9
2 Normative references. 9
3 Terms, definitions and symbols . 11
3.1 Definitions . 11
3.2 Symbols. 13
4 General precautions for measurements at high excitation level . 15
4.1 General statements. 15
4.2 Measuring coil . 15
4.3 Mounting of cores consisting of more than one part . 17
4.4 Measuring equipment. 19
5 Specimens . 23
6 Measuring procedures . 23
6.1 General procedure. 23
6.2 Measuring method for the (effective) amplitude permeability. 25
6.3 Measuring methods for the power loss. 29
7 Information to be stated . 33
8 Test report . 35
Annex A (informative) Basic circuits and related equipment for the measurement
of amplitude permeability . 37
Annex B (informative) Root-mean-square method for the measurement of power loss –
Example of a circuit and related procedure. 41
Annex C (informative) Multiplying methods for the measurement of power loss –
Basic circuits and related measurement procedures . 47
Annex D (informative) Reflection method for the measurement of power loss –
Basic circuit and related measurement procedures. 55
Annex E (informative) Calorimetric measurement methods for the measurement
of power loss. 59
62044-3 © IEC:2000 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CORES MADE OF SOFT MAGNETIC MATERIALS –
MEASURING METHODS –
Part 3: Magnetic properties at high excitation level
FOREWORD
1) The IEC (International Electrotechnical Commission) 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62044-3 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
51/573/FDIS 51/583/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 3.
Annexes A, B, C, D, and E are for information only.
IEC 62044, presented under the general title Cores made of soft magnetic materials –
Measuring methods, will include the following parts:
Part 1: Generic specification (under consideration)
Part 2: Magnetic properties at low excitation level (under consideration)
Part 3: Magnetic properties at high excitation level
Part 4: Non-magnetic properties (under consideration)
62044-3 © IEC:2000 – 7 –
Part 3 is the first to be published. IEC 60367-1 and IEC 60367-2 will be cancelled after parts
1, 2 and 3 of IEC 62044 are published.
This standard cancels and replaces 11.2 and annex J of IEC 60367-1. The remaining clauses
of IEC 60367-1 will be replaced by IEC 62044-1 and IEC 62044-2.
The committee has decided that the contents of this publication will remain unchanged
until 2006. At this date, the publication will be
reconfirmed;
withdrawn;
replaced by a revised edition, or
amended.
62044-3 © IEC:2000 – 9 –
CORES MADE OF SOFT MAGNETIC MATERIALS –
MEASURING METHODS –
Part 3: Magnetic properties at high excitation level
1 Scope
This standard provides measuring methods for power loss and amplitude permeability of
magnetic cores forming the closed magnetic circuits intended for use at high excitation levels
in inductors, chokes, transformers and similar devices for power electronics applications.
The methods given in this standard can cover the measurement of magnetic properties for
frequencies ranging practically from d.c. to 10 MHz, and even possibly higher, for the
calorimetric and reflection methods. The applicability of the individual methods to specific
frequency ranges is dependent on the level of accuracy that is to be obtained.
The methods in this standard are basically the most suitable for sine-wave excitations. Other
periodic waveforms can also be used; however, adequate accuracy can only be obtained if
the measuring circuitry and instruments used are able to handle and process the amplitudes
and phases of the signals involved within the frequency spectrum corresponding to the given
induction and field strength waveforms with only slightly degraded accuracy.
NOTE It may be necessary for some magnetically soft metallic materials to follow specific general principles,
customary for these materials, related to the preparation of specimens and prescribed calculations. These
principles are formulated in IEC 60404-8-6.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 62044. For dated references, subsequent
amendments to, or revisions of, any of these publications do not apply. However, parties to
agreements based on this part of IEC 62044 are encouraged to investigate the possibility of
applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of IEC
and ISO maintain registers of currently valid International Standards.
IEC 60050(221):1990, International Electrotechnical Vocabulary (IEV) – Chapter 221:
Magnetic materials and components
Amendment 1 (1993)
Amendment 2 (1999)
IEC 60205:1966, Calculation of the effective parameters of magnetic piece parts
IEC 60367-1:1982, Cores for inductors and transformers for telecommunications – Part 1:
Measuring methods
IEC 60401:1993, Ferrite materials – Guide on the format of data appearing in manufacturers’
catalogues of transformer and inductor cores
IEC 60404-8-6:1999, Magnetic materials – Part 8-6: Specifications for individual materials –
Soft magnetic metallic materials
IEC 61332:1995, Soft ferrite material classification
62044-3 © IEC:2000 – 11 –
3 Terms, definitions and symbols
3.1 Definitions
For the purposes of this International Standard, the following definitions apply in addition to
those of IEC 60050(221).
3.1.1
µ ,
(effective) amplitude permeability (symbols: amplitude permeability:
a
effective amplitude permeability: µ )
ea
ˆ
magnetic permeability obtained from the peak value of the effective magnetic induction, B ,
e
ˆ
H
and the peak value of the magnetic field strength, , at the stated value of either, when the
e
magnetic induction and magnetic field vary periodically with time and with an average of zero,
and the material is initially in a specified neutralized state
NOTE 1 This definition differs from that of IEC 60050 [221-03-07].
NOTE 2 Two amplitude permeabilities are in common use, namely:
– that in which the peak values apply to the actual waveforms of the induction and field strength,
– that in which the peak values apply to the fundamental components of waveforms of the induction
and the field strength.
NOTE 3 The induction and the field strength and, consequently, the amplitude permeability may even be quasi-
static quantities, provided the core is cyclically magnetized and no excursion of the B-H curve appears.
3.1.2
maximum (effective) amplitude permeability (symbol µ )
ea max
maximum value of the (effective) amplitude permeability when the amplitude of excitation
ˆ
ˆ
( B or H ) is varied
e e
NOTE This definition differs from that of IEC 60050 [221-03-10].
3.1.3
excitation
either induction or field strength for which the waveform and amplitude both remain within the
specified tolerance
NOTE When the induction (field strength) mode of excitation is chosen, the resultant waveform of field strength
(induction) may be distorted with respect to the excitation waveform due to the non-linear behaviour of the
magnetic material.
3.1.4
high excitation level
excitation at which the permeability depends on excitation amplitude (particularly at low
frequencies) and/or at which the power loss results in a noticeable temperature rise
(particularly at high frequencies)
3.1.5
sinusoidal excitation
excitation of harmonic content of less than 1 %
3.1.6
exciting winding
winding of measuring coil to which the exciting voltage is applied or through which the
exciting current is flowing
62044-3 © IEC:2000 – 13 –
3.1.7
voltage sensing winding
unloaded winding of a measuring coil across which the electromotive force induced by the
excitation may be determined
3.1.8
measuring winding
winding, usually secondary, loaded or unloaded, which can be used for measurement apart
from the exciting and/or voltage sensing winding
3.1.9
power loss
power absorbed by the core
3.2 Symbols
All the formulae in this standard use basic SI units. When multiples or sub-multiples are used,
the appropriate power of 10 shall be introduced.
A effective cross-sectional area of the core
e
ˆ
B peak value of the effective induction in the core
e
f frequency
ˆ
H peak value of the effective magnetic field strength in the core
e
l effective magnetic path length of the core
e
L inductance
i instantaneous value of the current
I current
N number of turns of winding of the measuring coil
P power loss in the core
Q quality factor of the core for a given frequency
c
R resistance
t time
T temperature
u instantaneous value of the voltage
U voltage
V effective volume of the core
e
δ relative error, deviation, etc.
∆ absolute error, deviation, etc.
µ (effective) amplitude permeability
ea
−7
µ magnetic constant = 4π ×10 H/m
π the number 3,14159.
ϕ phase shift
ω angular frequency = 2πf
NOTE 1 Additional subscript, upper script, etc. gives a more specific meaning to the given symbol.
NOTE 2 Symbols which are used sporadically are defined in the place where they appear in the text.
NOTE 3 Effective parameters, such as effective magnetic path length, l , effective cross-sectional area, A , and
e e
effective volume of the core, V , are calculated in accordance with IEC 60205.
e
NOTE 4 In the further text of this standard, the terms induction and field strength stand for the shortened terms
magnetic induction and magnetic field strength.
62044-3 © IEC:2000 – 15 –
4 General precautions for measurements at high excitation level
4.1 General statements
4.1.1 Relation to practice
The measuring conditions, methods and procedures shall be chosen in such a way that the
measured results are suitable for predicting the performance of the core under practical
circumstances. This does not imply that all these stipulations, especially those related to the
excitation waveforms, have to correspond to terms encountered in practice.
4.1.2 Core effective parameters and material properties
Since the core is in general of non-uniform cross-section and generally has non-uniformly
distributed windings along the core path, the measurement does not yield the amplitude
permeability and the power loss of the material, but the effective values of these parameters
ˆ
ˆ
appropriate to the effective induction B and the effective field strength H in the core.
e e
For the measurement of the amplitude permeability and the power loss of the material, the
core shall have a ring or toroidal shape in which the ratio of outer to inner diameter should not
be greater than 1,4 and should have windings distributed uniformly, close to the core, of
inductive coupling coefficient practically equal to unity.
4.1.3 Reproducibility of the magnetic state
To obliterate various remanence and time effects in the core material, the measurement shall
be made at a well-defined and reproducible magnetic state.
Any measurement under specified excitation, unless otherwise stated, is to be made at the
time t = t + ∆t after the magnetic conditioning start; t is the time period within which the
m c c
magnetic conditioning is completed and, whereupon, the specified excitation is set; ∆t is the
time period during which the core is kept stable under the excitation being set.
4.2 Measuring coil
4.2.1 The number of turns shall be specified for each winding in relation to the measuring
conditions, the equipment used and the accuracy to be obtained. The windings shall be
wound as close to the core as possible, to make the coupling (magnetic flux linkage)
coefficients between the measuring coil windings and the core and between the windings of
measuring coil, as close to 100 % as possible.
The resistance, self-capacitance and inter-winding capacitance of windings should be as low
as possible to make the related errors negligible.
In the case of ring or toroidal cores, the turns shall be distributed evenly around the core
circumference.
The connectors, primarily of exciting winding, should consist of insulated strands, if this is
necessary for measurements at high frequencies.
NOTE When winding a sharp-edge core, care should be taken to ensure that the wire insulation is not ruptured
and, in the case of stranded wire, strands are not broken.
62044-3 © IEC:2000 – 17 –
4.2.2 The use of a single winding both for excitation and voltage sensing is recommended if
– the coupling between the exciting winding and the voltage sensing winding is so reduced
that it results in a non-negligible error in the determination of the measuring induction B in
the core;
– the inter-winding capacitance is too high;
– there is no measuring circuitry contra-indication against the direct connection of the
exciting winding to input(s) of measuring instruments.
NOTE When single winding is used, it is recommended that its resistance be made as low as possible to make the
winding ohmic power loss negligible compared to the power loss in the core.
The use of separate exciting and voltage sensing windings (double winding) is recommended
if, for whatever reason, the exciting winding should be galvanically separated from the voltage
and the current measuring instruments, for example, to avoid a floating or d.c. connection to
their inputs.
NOTE 1 When the exciting and voltage sensing windings are used, it is critical to make their magnetic coupling
coefficient as close to 100 % as possible.
NOTE 2 When the voltage needed for calculation of the induction in the core is measured across the voltage
sensing winding then only the power loss in the core is determined with the exclusion of the ohmic power loss in
the current-carrying (exciting) winding.
NOTE 3 The use of two windings is recommended at more than 200 kHz.
4.3 Mounting of cores consisting of more than one part
The core, which consists of more than one part and which is to be assembled around the
measuring coil, shall be held together with glue, tape or a clamping device throughout the
measurement.
Whichever method is used to join the core parts together, it shall have the following
characteristics:
– distribution of the joining force uniformly over the mating surfaces, without the introduction
of bending stresses in the core;
– holding of all the core parts rigidly and without changing the position to each other;
– when a specified clamping method is used, an initial over-force of about 10 % shall be
applied when the core is closed, in order to break down fine irregularities between the
cleaned mating surfaces. Next, the specified clamping force ±5 % shall be applied;
− keeping the joining force constant within ±1 % during all measuring operations within all
measuring conditions, including the full specified temperature range.
The mounting of such cores shall be carried out in accordance with the following instructions.
The mating surface shall be inspected for damage and cleanness. Damaged cores shall
not be used. The mating surface shall be cleaned by non-abrasive means, for example,
by rubbing gently on a dry washing-leather. Next, the mating surfaces shall be degreased
if they have to be glued. Dust particles shall be blown off with clean dry compressed air.
The mating surfaces shall never be touched with bare fingers. The core parts shall then
be assembled around the measuring coil, the latter being locked in position with respect
to the core by suitable means, for example, a foam-washer. The core parts are centered
and glued or placed in clamping device. The glue, if used, shall be spread evenly on
the mating surface to form a film as thin as possible and then properly hardened.
62044-3 © IEC:2000 – 19 –
In the case where the clamping device is used, the clamping force specified in the relevant
specification shall be applied. The glued, taped or clamped cores shall relax under the
specified conditions (see clause 3 of IEC 60367-1) for a time sufficient to allow any variation
of stress effects, due to clamping, gluing or taping, to become negligible.
4.4 Measuring equipment
Any suitable measuring equipment may be used. Examples of appropriate circuits are given in
annexes A to E.
In addition to any requirement specified for the particular method and/or measuring circuit
used, the following general requirements shall be met.
4.4.1 To ensure the induction (field strength) mode of excitation, the output impedance of
the exciting source shall be low (high) compared with the series impedance of the exciting
winding of the measuring coil assembled with the core under test and the current sensing
resistor.
4.4.2 When the sinusoidal waveform of excitation is specified, the total harmonic content of
the excitation source shall be less than 1 %. When square pulses are specified, the relevant
requirements of clause 16 of IEC 60367-1 shall be met.
4.4.3 During the period of measurement, the excitation amplitude variations shall not exceed
±0,05 % and the frequency stability shall be adequate for the measuring method and the
equipment used.
4.4.4 The frequency range of voltmeters and other voltage sensing instruments shall include
all harmonics of the measured voltage having amplitudes of 1 % or more of their
fundamentals. This frequency range shall be specified in the relevant instrument specification.
4.4.5 The voltmeters and other voltage sensing instruments used shall be high-impedance
instruments, the connection of which will have only a negligible effect on the measuring
circuit, especially at high frequencies. The probes of a high-input resistance and a low-input
capacitance can reduce the load effects.
4.4.6 The accuracy of the voltmeters and/or voltage sensing instruments, determined for
the calibrating sinusoidal waveform, shall be within ±0,5 % for r.m.s. and average values and
±1 % for peak values, provided that the peak factor of waveforms to be measured is within
limits imposed by the instrument.
If inaccuracies exceed the above limits, only a sine-wave excitation of total harmonic content
less than 1 % is recommended and
− to determine the r.m.s., average and peak values of sinusoidal waveforms, a true r.m.s.
sensing voltmeter of accuracy within ±1 % is recommended. The average and peak values
are obtained by multiplying the indicated r.m.s. values by the following factors: average
value = 0,9 × r.m.s. value, peak value = 1,414 × r.m.s. value;
− to determine the r.m.s., average and peak values of non-sinusoidal waveforms, a digital
storage and processing oscilloscope or appropriate acquisition and processing instrument
shall be used. It shall be capable of capturing and processing the waveform with the
sampling rate not less than 150 samples per waveform period and the resolution not less
than 8 bits.
NOTE The peak factor is the ratio of the peak value to the r.m.s. value of measured waveform.
62044-3 © IEC:2000 – 21 –
4.4.7 The resistance of the in-series current sensing resistor shall be known with an
inaccuracy not exceeding ±1 digit on the third significant place, including possible thermal
variations of the resistance. A heat-sinking or cooled base of the resistor may moderate the
above thermal variations.
The inductance L of the resistor R over the frequency range specified in 4.4.4 shall not
exceed a value
R
ˆ
L ≤ 2δU
R
ω
m
where
R is the value of the resistor;
ω = 2πf f being equal to the highest frequency within the frequency range specified
m m
m
in 4.4.4;
ˆ ˆ
δU is the allowable relative increase in the voltage drop U across the resistor R,
R R
due to the inductance L, at frequency f .
m
Example
ˆ
For δU = 0,1 %, R = 1 Ω and the highest frequency f = 500 kHz, the inductance L shall be
R
m
3 –1 0,5
less than (2π× 500 × 10 ) × 1 × (2 × 0,001) = 14,2 nH.
The current sensing resistor can be replaced by an appropriately adapted current probe
provided that this does not reduce the amplitude and phase accuracy over the frequency
range as required in 4.4.4. In addition, the current probe shall be a linear device i.e. not
generating harmonics.
NOTE For the amplitude permeability measurement, it is the amplitude accuracy of the current probe which is
mainly concerned.
4.4.8 All the connections between the circuit components shall be as short as possible. In
addition, connections, if more than one, giving an additional non-equal phase shift shall be of
equal length and of the same type. Any phase shift ∆ϕ between the channels designed as
equiphase to lead the signals corresponding to the induction and field strength over the
frequency range defined in 4.4.4 shall not exceed a value
δP ( ∆ϕ )
∆ϕ = ± radian
Q
c
where
δP(∆ϕ) is that portion of the total inaccuracy of the power loss measurement which is
related to the phase shift ∆ϕ;
ˆ ˆ
ωB H
e e
Q = is the quality factor of the core under test;
c
2P
v
ω = 2πf is the angular frequency;
ˆ ˆ
B and H are the peak values of the effective induction and the effective field strength in
e e
the core, respectively;
P = P/V is the power-loss density; V is the effective volume of the core.
v e e
62044-3 © IEC:2000 – 23 –
If a non-sinusoidal excitation is applied, the phase shifts for the harmonics involved shall be
determined. Corresponding to each harmonic frequency, the values of the parameters listed
above have to be used in the calculation of each harmonic frequency.
Example
δP(∆ϕ) shall be within ±1 % and Q = 5 for a given core and measuring conditions. There-
fore, ∆ϕ shall be within ±0,01/5 = ±0,002 radian.
4.4.9 Any contact of any intermediary connectors, joints, switches, multiplexers, etc., which
is associated with the voltage or current measuring circuit, shall be able to transmit the
voltages involved and the conditioning and measuring currents of values specified in the
relevant specification. The contact resistance, phase shift, inductive and capacitive couplings,
series impedance and parallel admittance resulting from insertion of the contact shall have
only a negligible effect on the results measured over all the measuring conditions involved,
including the frequency range as specified in 4.4.4.
4.4.10 Measures and/or calibration should be taken to ensure that the resultant inaccuracy of
measurement for the amplitude permeability and the power loss over all the measuring
conditions does not exceed the inaccuracy specified for the given measuring method and
circuit specified in the appropriate annex.
4.4.11 A temperature-controlled environment shall be provided, capable of maintaining the
thermal equilibrium between the core and that environment within specified temperature limits
during the conditioning, setting, measurement and reading operations.
5 Specimens
Cores taken from normal production and forming closed magnetic circuits shall be used for
the measurement.
6 Measuring procedures
6.1 General procedure
6.1.1 The core to be measured is assembled with the measuring coil in accordance with 4.3.
In the case of ring and toroidal cores, apply winding(s) in accordance with 4.2.1.
6.1.2 The core shall be placed in a temperature-controlled environment in accordance
with 4.4.11. All measuring operations like magnetic conditioning, settings and measurement
shall be made after the temperature of the core is attained and maintained within allowed
tolerance limits.
ˆ
6.1.3 The voltages corresponding to the peak value of induction B and to the peak value of
e
ˆ
the field strength H at which the measurement has to be performed are calculated according
e
to the following formulae:
ˆ ˆ
–for B excitation: U = 4 ⋅ f ⋅ N ⋅ A ⋅ B
e av e e
where N is equal to N when a single winding (both for exciting and voltage sensing
functions) is used and N is equal to N when a secondary winding is used for the voltage
sensing;
62044-3 © IEC:2000 – 25 –
ˆ ˆ ˆ
–for H excitation: U = R ⋅ l ⋅ H / N
e R e e 1
The symbols are defined in 3.2, and N is the number of turns of the exciting winding.
ˆ ˆ
NOTE 1 For the practically pure sinusoidal waveform of induction B , the voltage, corresponding to B , can be
e e
ˆ
measured using also r.m.s. or peak reading voltmeters or instruments. The respective r.m.s., U , and peak, U ,
rms
values of this voltage are calculated as
ˆ
U = π ⋅ 2 ⋅ f ⋅ N ⋅ A ⋅ B
rms e e
ˆ ˆ
U = 2π ⋅ f ⋅ N ⋅ A ⋅ B
e e
ˆ
NOTE 2 If the current probe is used instead of the resistor R, the peak value of the current I corresponding
ˆ ˆ ˆ
to H is calculated as I = H ⋅ l / N .
e e e 1
NOTE 3 If a cross-section area other than A is used, for example A , for the calculation of U , this shall be
e min av
clearly stated in the relevant specification.
6.1.4 The core is conditioned by the electrical method in accordance with item 1) of 6.2 of
IEC 60367-1, unless otherwise stated.
6.1.5 At the specified time t after the start of the conditioning, the exciting source is set, as
c
quickly as possible, preferably within t = (2 ± 0,5) s for the time-dependent parameters, to
c
the required frequency, waveform and amplitude of excitation.
NOTE To keep the correct excitation waveform within all the measuring conditions, it should be under control. In
the case of the induction mode of excitation, the input of the control device should preferably be connected to a
separate voltage sensing winding.
6.1.6 At the time t , the measurement readings shall be taken and then the excitation
m
promptly turned off. The time period when the core is under specified excitation shall be as
short as possible but no longer than 10 s, to prevent the core from excessive self-heating.
6.1.7 When a core is excited under pulse conditions with or without a biasing component,
respective complementary stipulations of clause 16 of IEC 60367-1 shall be taken into
account.
6.2 Measuring method for the (effective) amplitude permeability
6.2.1 Purpose
To provide a method for the measurement of the (effective) amplitude permeability at high
excitation levels and symmetrical periodic waveforms of magnetic cores forming closed
magnetic circuits.
NOTE As an alternative, the peak value of the induction obtained at the specified peak value of the field strength
or, otherwise, the peak value of the field strength at the specified peak value of the induction may be determined.
6.2.2 Principle of the measurement
The induction and the field strength in a core are determined by measuring the average value
of voltage per half-period across the voltage sensing winding of the measuring coil wound on
the core and the peak value of the voltage across the resistor in series with the exciting
winding of that coil. The measurements are carried out at specified peak values either of
induction or field strength, frequency and temperature.
62044-3 © IEC:2000 – 27 –
6.2.3 Circuit and equipment
Any suitable equipment may be used provided that it is able to fulfil the function of the circuits
shown in annex A.
The requirements of 4.4 shall be met. Since the induction and field strength waveforms
are not critical in the case of measurement of the amplitude permeability, the requirements
of 4.4.1 and 4.4.2 need not be rigorously met.
NOTE If the amplitude permeability has to be determined for the peak values of fundamental components of the
waveforms of the induction and field strength, these peak values should be measured by frequency selective
instrument(s) observing the requirements of 4.4.
6.2.4 Measuring procedure
The general procedure of 6.1 shall be observed.
For the specified average value U of the voltage across the voltage sensing winding, either
av
ˆ
ˆ
the peak value U of the voltage across the resistor R or the peak value I of the current flowing
R
through the exciting winding is read.
ˆ ˆ
For the field strength excitation, the value of U is read at the specified value of either U or I .
av R
NOTE When the specification requires the induction to be measured at the specified field strength or, inversely,
the field strength at the specified induction, the specified peak value of the excitation is set, and either the
ˆ ˆ
resultant B or the resultant H is determined, respectively.
e e
6.2.5 Calculation
The (effective) amplitude permeability is derived from
ˆ
B l R U
e e av
µ = = ⋅
ea
ˆ ˆ
4µ fN N A
µ H 0 1 2 e U
0 e R
or if the current probe is used instead of resistor R
l U
e av
µ = ⋅
ea
ˆ
4µ fN N A
I
0 1 2 e
where
U is the average value of voltage across voltage sensing winding N ;
av
ˆ
U is the peak value of the voltage across the series resistor R;
R
ˆ
I is the peak value of the current flowing by the excitation winding N ;
N is the number of turns of the excitation winding N ;
1 1
N is the number of turns of the sensing winding N ;
2 2
the remaining symbols being defined in 3.2.
NOTE If the exciting and voltage sensing functions are performed only by the primary winding N , N is replaced
1 2
by N and the product N N is replaced by N .
1 1 2 1
62044-3 © IEC:2000 – 29 –
6.3 Measuring methods for the power loss
6.3.1 Purpose
To provide methods for the measurement of power loss at high excitation levels and periodic
waveforms in magnetic cores forming closed magnetic circuits.
6.3.2 Methods and principles of the measurements
The following methods are suitable according to the principle and application.
6.3.2.1 Root-mean-square method (r.m.s. method)
This method is
– generally applicable provided the circuit components, mounting and equipment used meet
the requirements of 4.4;
– less sensitive to distorted waveforms.
The r.m.s. value of the sum and the difference of the two voltages, the first across the
unloaded measuring winding of the measuring coil assembled with the core, and the second
across the resistor in series with the exciting winding of that coil, are measured by means of
the true r.m.s. voltmeter. The difference of the squares of these r.m.s. voltages is proportional
to the power loss in the core.
The related measuring procedure is given in annex B.
6.3.2.2 Multiplying methods
These methods, based on the identical voltage-current multiplying principle, are sensitive to
phase-shift errors.
The voltage related to the induction and the voltage related to the field strength in the core
are acquired, processed and multiplied by either analogue, digital or mixed way in the time or
frequency domain techniques. Some of these methods are shown in table 1.
Table 1 – Some multiplying methods and related domains of excitation waveforms,
acquisition, processing
Domain of
Subclause of
Measuring method
useable excitation
annex C
acquisition processing
waveform
V-A-W meter Sinusoidal Time Time C.1.1
Impedance analyser Sinusoidal Not applicable Not applicable C.1.2
Digitizing Arbitrary Time Time C.1.3
Vector spectrum Arbitrary Frequency Frequency C.1.4
Cross-power Arbitrary Time Frequency C.1.5
The related measuring procedures are given in annex C.
62044-3 © IEC:2000 – 31 –
6.3.2.2.1 V-A-W (volt – ampere – watt) meter method
This method is restricted to sinusoidal excitation as defined in 4.4.2.
A V-A-W meter multiplies internally the measured voltages and gives a time average of the
product of the instantaneous values of these voltages which is proportional to the power loss
of the core.
6.3.2.2.2 Impedance analyser method
This method is restricted to sinusoidal excitation as defined in 4.4.2.
The impedance analyser determines at the fundamental frequency the vector components of
the voltages related respectively to the induction and to the field strength in the core and
calculates a parallel resistance related to the power loss in the core. The square of the voltage
related to the induction divided by the parallel resistance gives the power loss in the core.
6.3.2.2.3 Digitizing method
This method is suitable for arbitrary excitation waveforms.
The measured voltages are sampled and converted into digital data by a digitizer. At each
sample point the product of the voltages involved is calculated. The power loss is proportional
to the average of the multiplied voltages over one cycle.
6.3.2.2.4 Vector spectrum method
This method is suitable for arbitrary excitation waveforms.
The amplitudes and the phase difference of the voltage signals are measured by a network
analyser. The measurements are made at the fundamental and harmonic frequencies of the
applied voltages.
The power loss in the core is obtained by adding up the power-loss components corres-
ponding to the fundamental and harmonic frequencies.
6.3.2.2.5 Cross-power method
This method is suitable for arbitrary excitation waveforms.
At the specified value of excitation, one or more cycles of the measured voltages are sampled
and converted into digital data.
The complex s
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...