SIST EN 61788-8:2011

Superconductivity - Part 8: AC loss measurements - Total AC loss measurement of round superconducting wires exposed to a transverse alternating magnetic field at liquid helium temperature by a pickup coil method (IEC 61788-8:2010)

This part of IEC 61788 specifies the measurement method of total AC losses by the pickup coil method in composite superconducting wires exposed to a transverse alternating magnetic field. The losses may contain hysteresis, coupling and eddy current losses. The standard method to measure only the hysteresis loss in DC or low-sweep-rate magnetic field is specified in IEC 61788-13 [2]. In metallic and oxide round superconducting wires expected to be mainly used for pulsed coil and AC coil applications, AC loss is generated by the application of time-varying magnetic field and/or current. The contribution of the magnetic field to the AC loss is predominant in usual electromagnetic configurations of the coil applications. For the superconducting wires exposed to a transverse alternating magnetic field, the present method can be generally used in measurements of the total AC loss in a wide range of frequency up to the commercial level, 50/60 Hz, at liquid helium temperature. For the superconducting wires with fine filaments, the AC loss measured with the present method can be divided into the hysteresis loss in the individual filaments, the coupling loss among the filaments and the eddy current loss in the normal conducting parts. In cases where the wires do not have a thick outer normal conducting sheath, the main components are the hysteresis loss and the coupling loss by estimating the former part as an extrapolated level of the AC loss per cycle to zero frequency in the region of lower frequency, where the coupling loss per cycle is proportional to the frequency.

Supraleitfähigkeit - Teil 8: Messung der Wechselstromverluste - Messung der Gesamtwechselstromverluste von runden Supraleiterdrähten in transversalen magnetischen Wechselfeldern mit Hilfe eines Pickupspulenverfahrens bei der Temperatur von flüssigem Helium (IEC 61788-8:2010)

Supraconductivité - Partie 8: Mesure des pertes en courant alternatif - Mesure de la perte totale en courant alternatif des fils supraconducteurs ronds exposés à un champ magnétique alternatif transverse par une méthode par bobines de détection (CEI 61788-8:2010)

L'IEC 61788-8:2010 spécifie la méthode de mesure par bobines de détection des pertes totales en courant alternatif des fils supraconducteurs composites exposés à un champ magnétique alternatif transverse. Les pertes peuvent contenir des pertes par hystérésis et des pertes par courants de Foucault. La méthode normalisée permettant de mesurer uniquement les pertes par hystérésis en courant continu ou en champ magnétique à faible vitesse de balayage est spécifiée dans la CEI 61788-13. Dans les fils supraconducteurs ronds métalliques et en oxyde dont la principale utilisation attendue concerne les applications avec bobines pulsées et bobines en courant alternatif, les pertes en courant alternatif sont générées par application d'un champ magnétique et/ou d'un courant variables dans le temps. La contribution du champ magnétique aux pertes en courant alternatif est prédominante dans les configurations électromagnétiques habituelles des applications avec bobines. Pour les fils supraconducteurs exposés à un champ magnétique alternatif transverse, la présente méthode peut généralement être utilisée dans les mesures des pertes totales en courant alternatif dans une large gamme de fréquences allant jusqu'aux fréquences de distribution à 50/60 Hz, à la température de l'hélium liquide. Pour les fils supraconducteurs avec des filaments fins, les pertes en courant alternatif mesurées avec la présente méthode peuvent être divisées en pertes par hystérésis dans chacun des filaments, pertes par couplage entre les filaments et pertes par courants de Foucault dans les parties conductrices normales. Lorsque les fils ne comportent pas de gaine conductrice normale externe épaisse, les principales composantes sont les pertes par hystérésis et les pertes par couplage en estimant la première partie comme un niveau extrapolé des pertes en courant alternatif par cycle jusqu'à la fréquence nulle dans la région des fréquences inférieures, les pertes par couplage par cycle étant proportionnelles à la fréquence. Cette deuxième édition annule et remplace la première édition parue en 2003, dont elle constitue une révision technique. Les principales modifications par rapport à l'édition précédente sont:
- l'extension des applications de la méthode par bobines de détection aux mesures des pertes en courant alternatif dans les fils supraconducteurs métalliques et en oxyde avec une section transversale ronde à la température de l'hélium liquide; et
- l'utilisation du mot "incertitude" pour les expressions statistique en lieu et place du mot "précision".
Mots clé: supraconductivité, TC90

Superprevodnost - 8. del: Meritve izmeničnih izgub - Meritve skupnih izmeničnih izgub okroglih superprevodnih žic, ki so izpostavljene transverzalnemu izmeničnemu magnetnemu polju pri temperaturi tekočega helija z odjemno tuljavo (IEC 61788-8:2010)

Ta del IEC 61788 določa merilno metodo izmeničnih izgub kompozitnih superprevodnih žic, ki so izpostavljene transverzalnemu izmeničnemu magnetnemu polju, z odjemno tuljavo. Izgube lahko vsebujejo histerezne izgube, izgube spojk in izgube vrtičnega toka. Standardna metoda za merjenje samo histereznih izgub enosmernega toka ali magnetnega polja z nizko hitrostjo valovanja, določenih v IEC 61788-13 [2]. V kovinskih in oksidnih okroglih žicah, za katere se pričakuje uporaba v glavnem za pulzne naprave s tuljavo in naprave, ki delujejo v izmeničnem toku s tuljavo, se izmenične izgube ustvarjajo z uporabo časovno spremenljivega magnetnega polja in/ali toka. Prispevek magnetnega polja k izmeničnim izgubam je prevladujoč pri običajnih elektromagnetnih konfiguracijah naprav s tuljavami. Za superprevodne žice, ki so izpostavljene transverzalnemu izmeničnemu magnetnemu polju, se pričujoča metoda lahko na splošno uporabi pri merjenjih skupnih izmeničnih izgub v širokem frekvenčnem razponu do komercialne ravni 50/60 Hz pri temperaturi tekočega helija. Za superprevodne žice s finimi vlakni se izmenične izgube, merjenje s pričujočo metodo. lahko ločijo na histerezne izgube na posamičnih vlaknih, izgube v spojkah med vlakni in izgube vrtičnega toka v običajno delujočih delih. V primerih, kjer žice nimajo debelega zunanjega običajno delujočega ovoja, so glavne komponente histerezne izgube in izgube v spojkah, ki jih ugotovimo z ocenjevanjem prejšnjega dela kot ekstrapolirane ravni izmeničnih izgub na cikel do nične frekvence na področju nizke frekvence, kjer so izgube v spojkah na cikel sorazmerne s frekvenco.

General Information

• Status: Published
• Publication Date: 20-Dec-2010
• ICS: 17.220.20 - Measurement of electrical and magnetic quantities
• ICS: 29.050 - Superconductivity and conducting materials
• Technical Committee: I09 - Imaginarni 09
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 10-Dec-2010
• Due Date: 14-Feb-2011
• Completion Date: 21-Dec-2010
• Ref Project: EN 61788-8:2010 - Superconductivity - Part 8: AC loss measurements - Total AC loss measurement of round superconducting wires exposed to a transverse alternating magnetic field at liquid helium temperature by a pickup coil method

Relations

• Replaces: SIST EN 61788-8:2003 - Superconductivity -- Part 8: AC loss measurements - Total AC loss measurement of Cu/Nb-Ti composite superconducting wires exposed to a transverse alternating magnetic field by a pickup coil method
• Effective Date: 29-Jan-2023
• Replaces: SIST EN 61788-8:2003 - Superconductivity -- Part 8: AC loss measurements - Total AC loss measurement of Cu/Nb-Ti composite superconducting wires exposed to a transverse alternating magnetic field by a pickup coil method
• Effective Date: 01-Oct-2013
• Replaces: SIST EN 61788-8:2003 - Superconductivity -- Part 8: AC loss measurements - Total AC loss measurement of Cu/Nb-Ti composite superconducting wires exposed to a transverse alternating magnetic field by a pickup coil method
• Effective Date: 07-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 61788-8:2011
01-februar-2011
1DGRPHãþD
SIST EN 61788-8:2003
6XSHUSUHYRGQRVWGHO0HULWYHL]PHQLþQLKL]JXE0HULWYHVNXSQLKL]PHQLþQLK
L]JXERNURJOLKVXSHUSUHYRGQLKåLFNLVRL]SRVWDYOMHQHWUDQVYHU]DOQHPX
L]PHQLþQHPXPDJQHWQHPXSROMXSULWHPSHUDWXULWHNRþHJDKHOLMD]RGMHPQRWXOMDYR
,(&
Superconductivity - Part 8: AC loss measurements - Total AC loss measurement of
round superconducting wires exposed to a transverse alternating magnetic field at liquid
helium temperature by a pickup coil method (IEC 61788-8:2010)
Supraleitfähigkeit - Teil 8: Messung der Wechselstromverluste - Messung der
Gesamtwechselstromverluste von runden Supraleiterdrähten in transversalen
magnetischen Wechselfeldern mit Hilfe eines Pickupspulenverfahrens bei der
Temperatur von flüssigem Helium (IEC 61788-8:2010)
Supraconductivité - Partie 8: Mesure des pertes en courant alternatif - Mesure de la
perte totale en courant alternatif des fils supraconducteurs ronds exposés à un champ
magnétique alternatif transverse par une méthode par bobines de détection (CEI 61788-
8:2010)
Ta slovenski standard je istoveten z: EN 61788-8:2010
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
29.050 Superprevodnost in prevodni Superconductivity and
materiali conducting materials
SIST EN 61788-8:2011 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 61788-8:2011

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SIST EN 61788-8:2011

EUROPEAN STANDARD
EN 61788-8

NORME EUROPÉENNE
November 2010
EUROPÄISCHE NORM

ICS 17.220 Supersedes EN 61788-8:2003


English version


Superconductivity -
Part 8: AC loss measurements -
Total AC loss measurement of round superconducting wires exposed to a
transverse alternating magnetic field at liquid helium temperature by a
pickup coil method
(IEC 61788-8:2010)

Supraconductivité -  Supraleitfähigkeit -
Partie 8: Mesure des pertes en courant Teil 8: Messung der
alternatif - Wechselstromverluste -
Mesure de la perte totale en courant Messung der
alternatif des fils supraconducteurs ronds Gesamtwechselstromverluste von runden
exposés à un champ magnétique alternatif Supraleiterdrähten in transversalen
transverse par une méthode par bobines magnetischen Wechselfeldern mit Hilfe
de détection eines Pickupspulenverfahrens bei der
(CEI 61788-8:2010) Temperatur von flüssigem Helium
(IEC 61788-8:2010)


This European Standard was approved by CENELEC on 2010-10-01. 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, Bulgaria, Croatia, Cyprus,
the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2010 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61788-8:2010 E

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SIST EN 61788-8:2011
EN 61788-8:2010 - 2 -
Foreword
The text of document 90/243/FDIS, future edition 2 of IEC 61788-8, prepared by IEC TC 90,
Superconductivity, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
EN 61788-8 on 2010-10-01.
This European Standard supersedes EN 61788-8:2003.
The main changes with respect to the previous edition are listed below:
– extending the applications of the pickup coil method to the a.c. loss measurements in metallic and
oxide superconducting wires with a round cross section at liquid helium temperature;
– u1 in accordance with the decision at the June 2006 IEC/TC90 meeting in Kyoto.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
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) 2011-07-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2013-10-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61788-8:2010 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
[2] IEC 61788-13:2003 NOTE  Harmonized as EN 61788-13:2003 (not modified).
[3] IEC 61788-1:2006 NOTE  Harmonized as EN 61788-1:2007 (not modified).
[9] IEC 61788-2 NOTE  Harmonized as EN 61788-2.
__________

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SIST EN 61788-8:2011
- 3 - EN 61788-8:2010
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  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 60050-815 2000 International Electrotechnical Vocabulary - -
(IEV) -
Part 815: Superconductivity

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SIST EN 61788-8:2011

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SIST EN 61788-8:2011
IEC 61788-8
®
Edition 2.0 2010-06
INTERNATIONAL
STANDARD


Superconductivity –
Part 8: AC loss measurements – Total AC loss measurement of round
superconducting wires exposed to a transverse alternating magnetic field
at liquid helium temperature by a pickup coil method


INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
V
ICS 17.220 ISBN 978-2-88912-007-9
® Registered trademark of the International Electrotechnical Commission

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SIST EN 61788-8:2011
– 2 – 61788-8 © IEC:2010(E)
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references .7
3 Terms and definitions .7
4 Principle .9
5 Apparatus.10
5.1 Testing apparatus .10
5.2 Pickup coils .10
5.3 Compensation circuit.10
6 Specimen preparation.11
6.1 Coiled specimen.11
6.1.1 Winding of specimen .11
6.1.2 Configuration of coiled specimen .11
6.1.3 Maximum bending strain.11
6.1.4 Treatment of terminal cross section of specimen .11
6.2 Specimen coil form.11
7 Testing conditions .11
7.1 External applied magnetic field.11
7.1.1 Amplitude of applied field .11
7.1.2 Direction of applied field .11
7.1.3 Waveform of applied field .12
7.1.4 Frequency of applied field .12
7.1.5 Uniformity of applied field .12
7.2 Setting of the specimen.12
7.3 Measurement temperature.12
7.4 Test procedure .12
7.4.1 Compensation .12
7.4.2 Measurement of background loss .12
7.4.3 Loss measurement .13
7.4.4 Calibration.13
8 Calculation of results .13
8.1 Amplitude of applied magnetic field .13
8.2 Magnetization.13
8.3 Magnetization curve .14
8.4 AC loss .14
8.5 Hysteresis loss.14
8.6 Coupling loss and coupling time constant [5,6] .14
9 Uncertainty.14
9.1 General .14
9.2 Uncertainty of measurement apparatus .15
9.3 Uncertainty of applied field .15
9.4 Uncertainty of measurement temperature .15
10 Test report.15
10.1 Identification of specimen.15

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SIST EN 61788-8:2011
61788-8 © IEC:2010(E) – 3 –
10.2 Configuration of coiled specimen.15
10.3 Testing conditions .16
10.4 Results.16
10.5 Measurement apparatus .16
10.5.1 Pickup coils .16
10.5.2 Measurement system.17
Annex A (informative) Additional information relating to Clauses 1 to 10 .19
Annex B (informative) Explanation of AC loss measurement with Poynting’s vector [10] .21
Annex C (informative) Estimation of geometrical error in the pickup coil method .22
Annex D (informative) Recommended method for calibration of magnetization and AC
loss.23
Annex E (informative)  Coupling loss for various types of applied magnetic field.25
Annex F (informative) Uncertainty considerations .26
Annex G (informative) Evaluation of uncertainty in AC loss measurement by pickup coil
method [13] .31
Bibliography.34

Figure 1 – Standard arrangement of the specimen and pickup coils .17
Figure 2 – A typical electrical circuit for AC loss measurement by pickup coils.18
Figure C.1 − Examples of calculated contour line map of the coefficient G.22
Figure D.1 – Evaluation of critical field from magnetization curves .24
Figure E.1 – Waveforms of applied magnetic field with a period T = 1/f.25

Table F.1 – Output signals from two nominally identical extensometers .27
Table F.2 – Mean values of two output signals.27
Table F.3 – Experimental standard deviations of two output signals.27
Table F.4 – Standard uncertainties of two output signals .28
Table F.5 – Coefficient of variations of two output signals.28
Table G.1 – Propagation of relative uncertainty in the pickup coil method (α = 0,5).33

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SIST EN 61788-8:2011
– 4 – 61788-8 © IEC:2010(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
__________

SUPERCONDUCTIVITY –

Part 8: AC loss measurements –
Total AC loss measurement of round
superconducting wires exposed to a transverse alternating
magnetic field at liquid helium temperature by a pickup coil method


FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in
addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses
arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61788-8 has been prepared by IEC technical committee 90:
Superconductivity.
This second edition cancels and replaces the first edition published in 2003. This edition
constitutes a technical revision.
The main changes with respect to the previous edition are listed below:
– extending the applications of the pickup coil method to the a.c. loss measurements in
metallic and oxide superconducting wires with a round cross section at liquid helium
temperature,
– u1 in accordance with the decision at the June 2006 IEC/TC90 meeting in Kyoto.

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SIST EN 61788-8:2011
61788-8 © IEC:2010(E) – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
90/243/FDIS 90/249/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 of the IEC 61788 series, under the general title: Superconductivity, 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 web site under "http://webstore.iec.ch" in the data related to
the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

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SIST EN 61788-8:2011
– 6 – 61788-8 © IEC:2010(E)
INTRODUCTION
Magnetometer and pickup coil methods are proposed for measuring the AC losses of composite
superconducting wires in transverse time-varying magnetic fields. These represent initial steps
in standardization of methods for measuring the various contributions to AC loss in transverse
fields, the most frequently encountered configuration.
It was decided to split the initial proposal mentioned above into two documents covering two
standard methods. One of them describes the magnetometer method for hysteresis loss and low
frequency (or sweep rate) total AC loss measurement, and the other describes the pickup coil
method for total AC loss measurement in higher frequency (or sweep rate) magnetic fields. The
frequency range is 0 Hz to 0,06 Hz for the magnetometer method and 0,005 Hz to 60 Hz for the
pickup coil method. The overlap between 0,005 Hz and 0,06 Hz is a complementary frequency
range for the two methods.
This standard covers the pickup coil method. The test method for standardization of AC loss
covered in this standard is partly based on the Versailles Project on Advanced Materials and
Standards (VAMAS) pre-standardization work on the AC loss of Nb-Ti composite
1)
superconductors [1] .
___________
1)
 Numbers in square brackets refer to the bibliography.

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SIST EN 61788-8:2011
61788-8 © IEC:2010(E) – 7 –
SUPERCONDUCTIVITY –

Part 8: AC loss measurements –
Total AC loss measurement of round
superconducting wires exposed to a transverse alternating
magnetic field at liquid helium temperature by a pickup coil method



1 Scope
This part of IEC 61788 specifies the measurement method of total AC losses by the pickup coil
method in composite superconducting wires exposed to a transverse alternating magnetic field.
The losses may contain hysteresis, coupling and eddy current losses. The standard method to
measure only the hysteresis loss in DC or low-sweep-rate magnetic field is specified in
IEC 61788-13 [2].
In metallic and oxide round superconducting wires expected to be mainly used for pulsed coil
and AC coil applications, AC loss is generated by the application of time-varying magnetic field
and/or current. The contribution of the magnetic field to the AC loss is predominant in usual
electromagnetic configurations of the coil applications. For the superconducting wires exposed
to a transverse alternating magnetic field, the present method can be generally used in
measurements of the total AC loss in a wide range of frequency up to the commercial level,
50/60 Hz, at liquid helium temperature. For the superconducting wires with fine filaments, the
AC loss measured with the present method can be divided into the hysteresis loss in the
individual filaments, the coupling loss among the filaments and the eddy current loss in the
normal conducting parts. In cases where the wires do not have a thick outer normal conducting
sheath, the main components are the hysteresis loss and the coupling loss by estimating the
former part as an extrapolated level of the AC loss per cycle to zero frequency in the region of
lower frequency, where the coupling loss per cycle is proportional to the frequency.
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 60050-815:2000, International Electrotechnical Vocabulary (IEV) – Part 815:
Superconductivity
3 Terms and definitions
For the purposes of this document, the following terms and definitions, as well as those of
IEC 60050-815, apply.
3.1
AC loss
P
power dissipated in a composite superconductor due to application of time-varying magnetic
field or electric current
[IEC 60050-815:2000, 815-04-54]

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SIST EN 61788-8:2011
– 8 – 61788-8 © IEC:2010(E)
3.2
hysteresis loss
P
h
loss of the type whose value per cycle is independent of frequency arising in a superconductor
under a varying magnetic field
NOTE This loss is caused by the irreversible magnetic properties of the superconducting material due to pinning of
flux lines.
[IEC 60050-815:2000, 815-04-55]
3.3
eddy current loss
P
e
loss arising in the normal conducting matrix of a composite superconductor or the structural
material when exposed to a varying magnetic field, either from an applied field or from a
self-field
[IEC 60050-815:2000, 815-04-56, modified]
3.4
(filament) coupling (current) loss
P
c
loss arising in multi-filamentary superconducting wires with a normal matrix due to coupling
current
[IEC 60050-815:2000, 815-04-59]
3.5
(filament)coupling time constant
τ
characteristic time constant of coupling current directed perpendicularly to filaments within
a strand for low frequencies
[IEC 60050-815:2000, 815-04-60]
3.6
shielding current
current induced by an external magnetic field applied to a superconductor and which includes
coupling current and eddy current after a field change in composite superconductors
3.7
critical (magnetic) field strength
H
c
magnetic field strength corresponding to the superconducting condensation energy at zero
magnetic field strength
[IEC 60050-815:2000, 815-01-21]
3.8
magnetization (of a superconductor)
magnetic moment divided by the volume of the superconductor
NOTE The macroscopic magnetic moment is also equal to the product of the shielding current and the area of
the closed path in a composite superconductor together with the magnetic moment of any penetrated trapped flux.

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SIST EN 61788-8:2011
61788-8 © IEC:2010(E) – 9 –
3.9
magnetization method for AC loss
method to determine the AC loss of materials from the area of the loop of the magnetization
curve
NOTE When pickup coils are used to measure the change in flux, which is then integrated to get the magnetization
of stationary coiled specimens, the method is called the pickup coil method.
[IEC 60050-815:2000, 815-08-15, modified]
3.10
pickup coil method
method to determine the AC loss of materials by evaluating electromagnetic power flow into the
materials by pickup coils
NOTE The pickup coil arrangement consists essentially of a primary winding (a superconducting magnet supplied
with a time varying current) and a pair of secondary windings (pickup coils), one of which (the main pickup coil)
contains the specimen to be measured and the other (the compensation coil) plays two roles: 1) it compensates the
signal from the main pickup coil when empty; 2) it supplies the field sweep information.
Here the coaxial and concentric arrangement of the pickup coils as shown in Figure 1 is used as the standard one for
the AC loss measurement. In order to obtain sufficient volume of the wire specimen to be measured and at the same
time to expose it to a transverse magnetic field, it must be wound into a coil. The specimen so prepared is also referred
to as the “coiled specimen”.
3.11
background loss
apparent loss obtained by the pickup coil method in the case where no specimen is located
inside the pickup coils
NOTE The background loss gives the experimental error in the system of the AC loss measurement by the pickup coil
method. It results from phase shift of electrical signal in the compensation process, an additional magnetic moment
induced in many components of experimental hardware, and external noise. The background loss can be reduced by
adjusting the experimental setup and compensated by subtracting it from measured AC loss as shown in 7.4.2.
3.12
effective cross-sectional area of the coiled specimen
total specimen volume divided by the larger of the specimen coil height or the pickup coil height
3.13
bending strain
ε
b
strain in percent arising from pure bending defined as ε = 100 r / R, where r is a half of
b
the specimen thickness and R is the bending radius
[IEC 60050-815:2000, 815-08-03]
NOTE In the pickup coil method, the coiled specimen by react and wind technique is prepared with an attention to the
permissive level of bending strain.
3.14
n-value (of a superconductor)
n
exponent obtained in a specific range of electric field strength or resistivity when the voltage
n
current U(I) curve is approximated by the equation U∝I
[IEC 60050-815:2000, 815-03-10]
4 Principle
The test consists of applying an alternating transverse magnetic field to a specimen and
detecting the magnetic moment of shielding currents induced in the specimen by m
...