Superconductivity - Part 24: Critical current measurement - Retained critical current after double bending at room temperature of Ag-sheathed Bi-2223 superconducting wires (IEC 61788-24:2018)

This part of IEC 61788 describes a test method for determining the retained critical current
after double bending at room temperature of short and straight Ag- and/or Ag alloy-sheathed
Bi-2223 superconducting wires that have the shape of a flat or square tape containing monoor
multicores of oxides. The wires can be laminated with copper alloy, stainless steel or Ni
alloy tapes.
The test method is intended for use with superconductors that have a critical current less than
300 A and an n-value larger than 5. The test to determine the retained critical current is
carried out without an applied magnetic field, with the test specimen immersed in a liquid
nitrogen open bath.

Supraleitfähigkeit - Teil 24: Messung des kritischen Stroms - Verbleibender kritischer Strom nach Doppelbiegung bei Raumtemperatur in Ag-ummantelten Bi-2223 supraleitenden Drähten

Supraconductivité - Partie 24: Mesurage du courant critique - Courant critique retenu après double flexion à température ambiante des fils supraconducteurs Bi-2223 avec gaine Ag

IEC 61788-24:2018 décrit une méthode d’essai permettant de déterminer le courant critique retenu après double flexion à température ambiante de fils supraconducteurs rectilignes courts Bi-2223 avec gaine Ag et/ou en alliage d’Ag, ayant la forme d’une bande plate ou carrée et contenant des noyaux simples ou plusieurs noyaux d’oxydes. Les fils peuvent être stratifiés avec des bandes en alliage de cuivre, en acier inoxydable ou en alliage de Ni. La méthode d’essai est destinée à être utilisée avec des supraconducteurs ayant un courant critique inférieur à 300 A et une valeur n supérieure à 5.

Superprevodnost - 24. del: Meritve kritičnega toka - Obdržani kritični tok po dvojnem upogibu posrebrenih Bi-2223 superprevodnih žic pri sobni temperaturi (IEC 61788-24:2018)

Ta del standarda IEC 61788 opisuje preskusno metodo za določanje obdržanega kritičnega toka
po dvojnem upogibu (pri sobni temperaturi) posrebrenih ali s srebrovo zlitino prevlečenih
Bi-2223 superprevodnih žic z obliko ravnega ali kvadratnega traku, ki vsebuje eno- ali
večjedrne okside. Žice so lahko laminirane s trakovi iz bakrene zlitine, nerjavnega jekla ali
nikljeve zlitine.
Preskusna metoda je namenjena za uporabo s superprevodniki, katerih kritični tok je manjši
od 300 A in n-vrednost večja od 5. Preskus za določanje obdržanega kritičnega toka
se izvede brez magnetnega polja, pri čemer je preskusni vzorec potopljen v odprto kopel
s tekočim dušikom.

General Information

Status
Published
Publication Date
17-Sep-2018
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
29-Aug-2018
Due Date
03-Nov-2018
Completion Date
18-Sep-2018

Buy Standard

Standard
SIST EN IEC 61788-24:2018 - BARVE na PDF-str 15,21,22,23,24,25,28
English language
32 pages
sale 10% off
Preview
sale 10% off
Preview

e-Library read for
1 day

Standards Content (sample)

SLOVENSKI STANDARD
SIST EN IEC 61788-24:2018
01-november-2018
6XSHUSUHYRGQRVWGHO0HULWYHNULWLþQHJDWRND2EGUåDQLNULWLþQLWRNSR
GYRMQHPXSRJLEXSRVUHEUHQLK%LVXSHUSUHYRGQLKåLFSULVREQLWHPSHUDWXUL
,(&

Superconductivity - Part 24: Critical current measurement - Retained critical current after

double bending at room temperature of Ag-sheathed Bi-2223 superconducting wires
(IEC 61788-24:2018)

Supraleitfähigkeit - Teil 24: Messung des kritischen Stroms - Verbleibender kritischer

Strom nach Doppelbiegung bei Raumtemperatur in Ag-ummantelten Bi-2223
supraleitenden Drähten

Supraconductivité - Partie 24: Mesurage du courant critique - Courant critique retenu

après double flexion à température ambiante des fils supraconducteurs Bi-2223 avec

gaine Ag
Ta slovenski standard je istoveten z: EN IEC 61788-24:2018
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
29.050 Superprevodnost in prevodni Superconductivity and
materiali conducting materials
29.060.10 Žice Wires
SIST EN IEC 61788-24:2018 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN IEC 61788-24:2018
---------------------- Page: 2 ----------------------
SIST EN IEC 61788-24:2018
EUROPEAN STANDARD EN IEC 61788-24
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2018
ICS 29.050; 77.040.10; 17.220
English Version
Superconductivity - Part 24: Critical current measurement -
Retained critical current after double bending at room
temperature of Ag-sheathed Bi-2223 superconducting wires
(IEC 61788-24:2018)

Supraconductivité - Partie 24: Mesurage du courant critique Supraleitfähigkeit - Teil 24: Messung des kritischen Stroms

- Courant critique retenu après double flexion à température - Verbleibender kritischer Strom nach Doppelbiegung bei

ambiante des fils supraconducteurs Bi-2223 avec gaine Ag Raumtemperatur in Ag-ummantelten Bi-2223

(IEC 61788-24:2018) supraleitenden Drähten
(IEC 61788-24:2018)

This European Standard was approved by CENELEC on 2018-07-23. 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 CEN-CENELEC

Management Centre 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 CEN-CENELEC Management Centre 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

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

Switzerland, Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2018 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 61788-24:2018 E
---------------------- Page: 3 ----------------------
SIST EN IEC 61788-24:2018
EN IEC 61788-24:2018 (E)
European foreword

The text of document 90/402/FDIS, future edition 1 of IEC 61788-24, prepared by IEC/TC 90

"Superconductivity" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as

EN IEC 61788-24:2018.
The following dates are fixed:

• latest date by which the document has to be implemented at national (dop) 2019-04-23

level by publication of an identical national standard or by endorsement

• latest date by which the national standards conflicting with the (dow) 2021-07-23

document have to be withdrawn

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice

The text of the International Standard IEC 61788-24:2018 was approved by CENELEC as a European

Standard without any modification.

In the official version, for Bibliography, the following note has to be added for the standard indicated:

IEC 61788-3 NOTE Harmonized as EN 61788-3
---------------------- Page: 4 ----------------------
SIST EN IEC 61788-24:2018
EN IEC 61788-24:2018 (E)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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 1 Where an International Publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:

www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60050-815 2015 International Electrotechnical Vocabulary - - -
Part 815: Superconductivity
---------------------- Page: 5 ----------------------
SIST EN IEC 61788-24:2018
---------------------- Page: 6 ----------------------
SIST EN IEC 61788-24:2018
IEC 61788-24
Edition 1.0 2018-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Superconductivity –
Part 24: Critical current measurement – Retained critical current after double
bending at room temperature of Ag-sheathed Bi-2223 superconducting wires
Supraconductivité –
Partie 24: Mesurage du courant critique – Courant critique retenu après double
flexion à température ambiante des fils supraconducteurs Bi-2223 avec gaine Ag
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220; 29.050; 77.040.10 ISBN 978-2-8322-5801-9

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 7 ----------------------
SIST EN IEC 61788-24:2018
– 2 – IEC 61788-24:2018 © IEC 2018
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms and definitions ...................................................................................................... 7

4 Principle .......................................................................................................................... 8

5 Apparatus ........................................................................................................................ 8

5.1 General ................................................................................................................... 8

5.2 Bending mandrel ..................................................................................................... 8

5.3 Critical current measurement holder ....................................................................... 8

5.4 Critical current measuring system ........................................................................... 9

6 Specimen preparation and set up .................................................................................... 9

6.1 Length of specimen ................................................................................................. 9

6.2 Mounting of the specimen ..................................................................................... 10

7 Measurement procedures .............................................................................................. 10

7.1 Critical current measurement ................................................................................ 10

7.2 Double bending ..................................................................................................... 10

7.3 Retained critical current after bending ................................................................... 11

8 Calculation of results ..................................................................................................... 11

8.1 Critical current criteria........................................................................................... 11

8.2 n-value (optional) .................................................................................................. 11

9 Test report ..................................................................................................................... 11

9.1 Identification of test specimen ............................................................................... 11

9.2 Report of I values and/or retained I ratio ........................................................... 12

c c

9.3 Report of I test conditions ................................................................................... 12

Annex A (informative) Additional information relating to Clauses 1 to 9 ................................ 13

A.1 General ................................................................................................................. 13

A.2 Measurement condition ......................................................................................... 13

A.3 Apparatus measurement holder material ............................................................... 13

A.4 Specimen preparation ........................................................................................... 16

A.5 Measurement procedures ...................................................................................... 16

A.5.1 Critical current measurement ......................................................................... 16

A.5.2 Bending ......................................................................................................... 18

A.6 Calculation of results ............................................................................................ 19

A.6.1 Critical current criteria ................................................................................... 19

A.6.2 n-value .......................................................................................................... 19

A.7 Relative standard uncertainty ................................................................................ 20

Annex B (informative) Evaluation of combined standard uncertainty for the retained I

after double bending ............................................................................................................. 22

B.1 Practice of critical current measurement ............................................................... 22

B.2 Model equation ..................................................................................................... 22

B.3 Operation for the retained I measurement ........................................................... 23

B.4 Combined standard uncertainty ............................................................................. 23

---------------------- Page: 8 ----------------------
SIST EN IEC 61788-24:2018
IEC 61788-24:2018 © IEC 2018 – 3 –

B.5 Evaluation of standard uncertainty (SU) for each measurand ................................ 24

B.5.1 Voltage tap length (L) .................................................................................... 24

B.5.2 Voltage (U) .................................................................................................... 24

B.5.3 Current (I) ..................................................................................................... 25

B.6 Evaluation of combined standard uncertainty ........................................................ 26

Bibliography .......................................................................................................................... 29

Figure 1 – Sample holder ........................................................................................................ 9

Figure 2 – Intrinsic U-I characteristic .................................................................................... 12

Figure 3 – U-I characteristic with a current transfer component ............................................. 12

Figure A.1 – Measurement configuration for a few hundred ampere class conductor ............. 15

Figure A.2 – Clips ................................................................................................................. 15

Figure A.3 – Additional strain caused by voltage tap wires and solders ................................. 16

Figure A.4 – Boiling temperature of liquid nitrogen versus atmospheric pressure ................. 17

Figure A.5 – Critical current versus temperature for a typical Bi-2223 wire ............................ 18

Figure A.6 – Bending process ............................................................................................... 19

Figure B.1 – U-I diagram ...................................................................................................... 22

Figure B.2 – Bending diameter dependence of the retained I and , where the
c COV

calculated curve of I /I gives Equation (B.24).................................................................... 28

c c0
Table A.1 – Thermal expansion data of Bi-2223 superconductors and selected

materials ............................................................................................................................... 14

Table A.2 – Average of the degree of retained critical current (I /I ), their relative

c c0

standard uncertainty and coefficient of variance.................................................................... 21

Table B.1 – Precondition for evaluating standard uncertainty ................................................ 22

Table B.2 – Partial sum (Equation (B.17) of standard uncertainty as related to the

current measurement) ........................................................................................................... 26

Table B.3 – Budget table of standard uncertainty for each component .................................. 27

Table B.4 – Combined standard uncertainty .......................................................................... 27

---------------------- Page: 9 ----------------------
SIST EN IEC 61788-24:2018
– 4 – IEC 61788-24:2018 © IEC 2018
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SUPERCONDUCTIVITY –
Part 24: Critical current measurement –
Retained critical current after double bending at room
temperature of Ag-sheathed Bi-2223 superconducting wires
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 61788-24 has been prepared by IEC technical committee 90:

Superconductivity:
The text of this standard is based on the following documents:
FDIS Report on voting
90/402/FDIS 90/406/RVD

Full information on the voting for the approval of this International Standard can be found in

the report on voting indicated in the above table.

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

---------------------- Page: 10 ----------------------
SIST EN IEC 61788-24:2018
IEC 61788-24:2018 © IEC 2018 – 5 –

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

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct

understanding of its contents. Users should therefore print this document using a

colour printer.
---------------------- Page: 11 ----------------------
SIST EN IEC 61788-24:2018
– 6 – IEC 61788-24:2018 © IEC 2018
INTRODUCTION

In 1988, a new class of high critical temperature (T ) copper oxide superconductors,

Bi-Sr-Ca-Cu-O, was discovered. After nearly three decades, (Bi,Pb) Sr Ca Cu O (Bi-2223)

2 2 2 3 x
is now being utilized as a commercial high-T superconducting wire.

Superconducting wires are often subjected to bending deformation during production and

application, e.g. during wire processing, magnet construction, cable fabrication, etc. The wire

is bent towards both the upper and lower directions as it passes through several pulleys.

These production processes are carried out at room temperature. Critical current of the wire is

likely influenced through such bending, and may be accompanied by irreversible degradation

in case of large deformation. The easiest way to evaluate the influence of bending on critical

current is to carry out comparative measurement with the wire in the straight form before and

after bending to a specific diameter.

After a wire is made into a coil or a cable, critical current is often measured under bending

conditions or a more complex deformation state. In these cases, change in critical current

may include both reversible and irreversible contributions depending on the amount of

deformation. Irreversible degradation usually originates from a fracture in the superconducting

component. In order to evaluate only irreversible contributions, measuring the retained critical

current after the wire is straightened back from its deformed shape is necessary.

The critical bending diameter below which wire performance degrades significantly is typically

specified for use of commercial superconducting wire. Thus, it is important to standardize

measurement methods for the retained critical current after double bending. This document

can be applied to other similar bending tests such as single bending, cyclic bending, etc.

This document consists of two fundamental technologies of the critical current measurement

and the double bending process.
---------------------- Page: 12 ----------------------
SIST EN IEC 61788-24:2018
IEC 61788-24:2018 © IEC 2018 – 7 –
SUPERCONDUCTIVITY –
Part 24: Critical current measurement –
Retained critical current after double bending at room
temperature of Ag-sheathed Bi-2223 superconducting wires
1 Scope

This part of IEC 61788 describes a test method for determining the retained critical current

after double bending at room temperature of short and straight Ag- and/or Ag alloy-sheathed

Bi-2223 superconducting wires that have the shape of a flat or square tape containing mono-

or multicores of oxides. The wires can be laminated with copper alloy, stainless steel or Ni

alloy tapes.

The test method is intended for use with superconductors that have a critical current less than

300 A and an n-value larger than 5. The test to determine the retained critical current is

carried out without an applied magnetic field, with the test specimen immersed in a liquid

nitrogen open bath.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their

content constitutes requirements 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 60050-815:2015, International Electrotechnical Vocabulary – Part 815: Superconductivity

(available at http://www.electropedia.org/)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60050-815 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
double bending

bending in one direction to a certain diameter followed by the subsequent bending in the

opposite direction to the same diameter

Note 1 to entry: Bending diameter is defined as the diameter of the bending mandrel.

Note 2 to entry: The definition of bending diameter is in principle the sum of the mandrel diameter and

superconductor thickness. In the engineering process, however, the minimum diameter of the pulleys through

which the wire is passed should also be considered.
---------------------- Page: 13 ----------------------
SIST EN IEC 61788-24:2018
– 8 – IEC 61788-24:2018 © IEC 2018
3.2
constant sweep rate method

voltage-current data (U-I data) acquisition method where a current is swept at a constant rate

from zero to a value above critical current (I ) while continuously or frequently and

periodically acquiring U-I data
3.3
ramp-and-hold method

U-I data acquisition method where a current is ramped to a number of appropriately

distributed points along the U-I curve and held constant at each of these points while

acquiring a number of voltages and current readings
4 Principle

The principle of the double bending method is described as follows. Critical current at 77 K

under self-field shall be measured in a straight configuration with no mechanical strain. After

measurement the specimen shall be warmed up to room temperature.

Hereafter, the specimen shall be bent in one direction to the specified diameter and then

returned to the straight configuration. Successively, the specimen shall be bent in the

opposite direction to the same diameter and returned to the straight configuration again.

Critical current of the specimen at 77 K under self-field shall be measured after double

bending and straightening. The time interval between critical current measurements before

and after bending should be as short as possible.

Critical current is determined from voltage-current (U-I) characteristic measured in a liquid

nitrogen open bath under a constant pressure. Critical current is determined as the current at

a specific electric field strength criterion (electric field criterion) (E ), which corresponds to the

voltage criterion (U ) for a specified voltage tap separation.
5 Apparatus
5.1 General
The apparatuses required for the present test methods include the following:
• mandrels with necessary bending diameters;
• critical current measuring system.
5.2 Bending mandrel

Bending diameter shall be defined as the diameter of the bending mandrel. Bendable length

shall be longer than the distance between the voltage taps.
5.3 Critical current measurement holder
The measurement holder is constructed from an insulating material.

Critical current may inevitably depend on the measurement holder material due to specimen

strain induced by the difference of thermal contraction between specimen and holder.

The structure of the measurement holder shall be one which does not induce a local excess

strain. The specimen strain induced by the difference of thermal contraction between

specimen and holder during cooling from room temperature to 77 K shall be minimized to

within ± 0,1 %. This thermal strain can be evaluated in cases where the thermal expansion

---------------------- Page: 14 ----------------------
SIST EN IEC 61788-24:2018
IEC 61788-24:2018 © IEC 2018 – 9 –

coefficients of constituent materials are known. To minimize the thermal strain, the holder

shall be constructed from material which has a thermal contraction similar to the specimen.

NOTE Recommended measurement holder materials are described in A.3.
5.4 Critical current measuring system

The apparatus to measure U-I characteristics consists of a specimen probe, an open bath of

liquid nitrogen and a U-I measurement system.

The specimen probe, which consists of a specimen, a measurement holder and a specimen

support structure, is inserted in the open bath filled with liquid nitrogen. The U-I measurement

system consists of a direct current source, a recorder and necessary preamplifiers, filters or

voltmeters, or a combination thereof.
A computer-assisted data acquisition system is recommended.
6 Specimen preparation and set up
6.1 Length of specimen

The length (L) of the specimen to be measured shall be determined as follows (see Figure 1):

L = 2 × L + 2 × L + L + 2 × L > 5 × W (1)
2 4 1 3
L ≥ W, L ≥ W, L ≥ W (2)
1 2 3
where
L is the distance between the voltage taps;
L is the length of the current contact;
L is the shortest distance from the current contact to the voltage tap;
L is the width of the voltage tap;
W is the width of the specimen to be measured.
L L L L L L L
2 3 4 1 4 3 2
Current
Current Voltage
Voltage
IEC
Figure 1 – Sample holder

For a specimen with a larger current-carrying capacity/width, L shall be longer than 3W. In

cases where the specimen is laminated with stainless steel or laminated with another highly

resistive material, L shall be larger. For measurement which requires higher voltage

sensitivity, L shall be larger. In cases where current transfer voltage cannot be ignored, L shall

1 3
be larger.
---------------------- Page: 15 ----------------------
SIST EN IEC 61788-24:2018
– 10 – IEC 61788-24:2018 © IEC 2018

In Table 2 of [1] , five successful double bend test conditions are shown. Typically, specimen

length L ranges from 90 mm to 150 mm, L from 18,25 mm to 50 mm, L from 10 mm to
1 2
20 mm, L from 12,5 mm to 20 mm, and
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.