SIST EN IEC 61788-27:2025

Superconductivity - Part 27: Twist pitch measurement of practical superconducting wires - Twist pitch measurement of nb‑ti/cu and nb‑sn/cu composite superconductors (IEC 61788-27:2025)

IEC 61788-27:2025 specifies a test method for the twist pitch measurement of Nb‑Ti/Cu and Nb‑Sn/Cu composite superconductors by an untwisting method.
The test method is applicable to Nb‑Ti/Cu and Nb‑Sn/Cu composite superconducting wires with monolithic structures, which have either a round cross section with a diameter ranging from 0,2 mm to 2 mm or a rectangular cross section that is equivalent in area to the round cross‑sectional wires. These wires possess a filament diameter ranging from 6 µm to 200 µm, a twist pitch between 5 mm and 50 mm, and a matrix of copper or copper alloy. This document uses nitric acid to remove the matrix (copper or copper alloy), so the surface of the composite superconducting wire can be plated with a material that is dissolvable by nitric acid.
Though uncertainty can increase, the method can apply to Nb‑Ti/Cu or Nb‑Sn/Cu composite superconducting wires when the parameters of cross-sectional area, filament diameter and twist pitch are out of the limit.
The test method specified in this document is expected to apply to other types of composite superconducting wires after some appropriate modifications.

Supraleitfähigkeit - Teil 27: Messung der Schlaglänge von technischen supraleitenden Drähten - Messung der Schlaglänge von Nb-Ti/Cu- und Nb-Sn/Cu-Verbund-Supraleitern (IEC 61788-27:2025)

Supraconductivité - Partie 27: Mesurage du pas de torsade de fils supraconducteurs pratiques - Mesurage du pas de torsade des composites supraconducteurs Nb‑Ti/Cu et Nb‑Sn/Cu (IEC 61788-27:2025)

L'IEC 61788-27:2025 spécifie une méthode d'essai pour le mesurage du pas de torsade des composites supraconducteurs Nb‑Ti et Nb‑Sn/Cu par une méthode de détorsadage.
La méthode d'essai s'applique aux fils supraconducteurs composites Nb‑Ti/Cu et Nb‑Sn/Cu à structure monolithique, de section ronde d'un diamètre compris entre 0,2 mm et 2 mm ou de section rectangulaire dont la surface est équivalente à celle des fils à section ronde. Ces fils possèdent un diamètre de filament compris entre 6 µm et 200 µm, un pas de torsade compris entre 5 mm et 50 mm, et une matrice de cuivre ou d'alliage de cuivre. Le présent document utilise l'acide nitrique pour éliminer la matrice (cuivre ou alliage de cuivre), de sorte que la surface du fil supraconducteur composite puisse être revêtue d'un matériau dissoluble par l'acide nitrique.
Même si l'incertitude peut augmenter, la méthode peut s'appliquer aux fils supraconducteurs composites Nb‑Ti/Cu ou Nb‑Sn/Cu lorsque les paramètres de section, de diamètre de filament et de pas de torsade sont en dehors des limites.
Il est prévu que la méthode d'essai spécifiée dans le présent document s'applique à d'autres types de fils supraconducteurs composites après quelques modifications appropriées.

Superprevodnost - 27. del: Merjenje naklona praktičnih superprevodnih žic - Metoda merjenja naklona kompozitnih superprevodnikov nb‑ti/cu in nb‑sn/cu (IEC 61788-27:2025)

General Information

• Status: Published
• Public Enquiry End Date: 29-Feb-2024
• Publication Date: 08-May-2025
• 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: 16-Apr-2025
• Due Date: 21-Jun-2025
• Completion Date: 09-May-2025
• Ref Project: EN IEC 61788-27:2025 - Superconductivity - Part 27: Twist pitch measurement of practical superconducting wires - Twist pitch measurement of Nb‑Ti/Cu and Nb‑Sn/Cu composite superconductors

Standards Content (Sample)

SLOVENSKI STANDARD
01-junij-2025
Superprevodnost - 27. del: Merjenje naklona praktičnih superprevodnih žic -
Metoda merjenja naklona kompozitnih superprevodnikov nb‑ti/cu in nb‑sn/cu
(IEC 61788-27:2025)
Superconductivity - Part 27: Twist pitch measurement of practical superconducting wires
- Twist pitch measurement of nb‑ti/cu and nb‑sn/cu composite superconductors (IEC
61788-27:2025)
Supraleitfähigkeit - Teil 27: Messung der Schlaglänge von technischen supraleitenden
Drähten - Messung der Schlaglänge von Nb-Ti/Cu- und Nb-Sn/Cu-Verbund-Supraleitern
(IEC 61788-27:2025)
Supraconductivité - Partie 27: Mesurage du pas de torsade de fils supraconducteurs
pratiques - Mesurage du pas de torsade des composites supraconducteurs Nb‑Ti/Cu et
Nb‑Sn/Cu (IEC 61788-27:2025)
Ta slovenski standard je istoveten z: EN IEC 61788-27:2025
ICS:
17.220.20 Merjenje električnih in Measurement of electrical
magnetnih veličin and magnetic quantities
29.050 Superprevodnost in prevodni Superconductivity and
materiali conducting materials
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61788-27

NORME EUROPÉENNE
EUROPÄISCHE NORM April 2025
ICS 29.050
English Version
Superconductivity - Part 27: Twist pitch measurement of
practical superconducting wires - Twist pitch measurement of
Nb-Ti/Cu and Nb-Sn/Cu composite superconductors
(IEC 61788-27:2025)
Supraconductivité - Partie 27: Mesurage du pas de torsade Supraleitfähigkeit - Teil 27: Messung der Schlaglänge von
de fils supraconducteurs pratiques - Mesurage du pas de technischen supraleitenden Drähten - Messung der
torsade des composites supraconducteurs Nb-Ti/Cu et Nb- Schlaglänge von Nb-Ti/Cu- und Nb-Sn/Cu-Verbund-
Sn/Cu Supraleitern
(IEC 61788-27:2025) (IEC 61788-27:2025)
This European Standard was approved by CENELEC on 2025-04-01. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye 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
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61788-27:2025 E

European foreword
The text of document 90/532/FDIS, future edition 1 of IEC 61788-27, prepared by TC 90
"Superconductivity" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2026-04-30
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2028-04-30
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.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 61788-27:2025 was approved by CENELEC as a European
Standard without any modification.

IEC 61788-27 ®
Edition 1.0 2025-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Superconductivity –
Part 27: Twist pitch measurement of practical superconducting wires – Twist

pitch measurement of Nb‑Ti/Cu and Nb‑Sn/Cu composite superconductors

Supraconductivité –
Partie 27: Mesurage du pas de torsade de fils supraconducteurs pratiques –

Mesurage du pas de torsade des composites supraconducteurs Nb‑Ti/Cu et

Nb‑Sn/Cu
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.050  ISBN 978-2-8327-0133-1

– 2 – IEC 61788-27:2025 © IEC 2025
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
4 Principle . 9
5 Reagents and auxiliary materials . 10
6 Apparatus and tools . 10
7 Specimen preparation . 10
7.1 Requirements . 10
7.2 Cleaning . 10
7.3 Drying . 10
7.4 Removing matrix copper and sanding barrier (apply to Nb-Sn/Cu specimen
of external stabilizer type only) . 11
8 Measurement procedure . 11
8.1 Specimen fixing . 11
8.2 Specimen dissolution . 11
8.3 Cleaning and drying . 11
8.4 Measurement . 12
9 Calculation of results . 12
10 Uncertainty of measurement . 12
11 Test report . 13
11.1 Specimen . 13
11.2 Results . 13
Annex A (normative) Measurement – Direct measurement method . 14
A.1 Method . 14
A.2 Measurement procedure . 14
A.2.1 Specimen dissolution . 14
A.2.2 Cleaning and drying . 14
A.2.3 Measurement . 15
A.3 Uncertainty of measurement . 15
A.4 Test report . 15
Annex B (normative) Measurement – Image processing method . 16
B.1 Method . 16
B.2 Measurement procedure . 17
B.2.1 Specimen dissolution . 17
B.2.2 Cleaning and drying . 17
B.2.3 Photo taking . 17
B.2.4 Measuring the helix angle . 17
B.2.5 Result and rounding method . 18
B.3 Uncertainty of measurement . 18
B.4 Test report . 18
Annex C (informative) A typical design of the auxiliary tool for twist pitch
measurement by the untwisting method . 19
C.1 Apparatus of twist angle measurement . 19
C.2 Measurement procedure . 20

IEC 61788-27:2025 © IEC 2025 – 3 –
Annex D (informative) Uncertainty evaluation . 22
D.1 Untwisting method . 22
D.1.1 Mathematical model . 22
D.1.2 Measurement uncertainty in twist pitch L for Nb-Ti/Cu . 22
p
D.1.3 Measurement uncertainty in twist pitch L for Nb-Sn/Cu . 24
p
D.1.4 Round robin test . 26
D.1.5 Other influences of uncertainty . 27
D.2 Direct measurement method . 28
D.2.1 Mathematical model . 28
D.2.2 Procedures of standard uncertainty evaluation . 28
D.2.3 Specimen identification . 29
D.2.4 Evaluation of each standard uncertainty component . 29
D.2.5 Evaluation results of combined standard uncertainty in twist pitch L . 30
p
D.2.6 Expanded uncertainty in twist pitch L . 30
p
D.2.7 Round robin test . 30
D.3 Image processing method . 32
D.3.1 Mathematical model . 32
D.3.2 Procedures of standard uncertainty evaluation . 32
D.3.3 Specimen identification . 33
D.3.4 Evaluation of each standard uncertainty component . 33
D.3.5 Evaluation results of combined standard uncertainty in twist pitch L . 35
p
D.3.6 Expanded uncertainty in twist pitch L . 35
p
D.3.7 Round robin test . 35
Bibliography . 37

Figure 1 – Principle demonstration . 9
Figure B.1 – Principle demonstration for image processing method . 16
Figure B.2 – Measurement of helix angle . 18
Figure C.1 – A typical design of the auxiliary tool for twist pitch measurement . 20
Figure C.2 – Specimen fixing .
...