IEC TR 62981:2017

Studies and comparisons of magnetic measurements on grain-oriented electrical steelsheet determined by the single sheet test method and Epstein test method

IEC TR 62981:2017(E), which is a Technical Report, provides the results of international exercises and comparisons focusing on achieving the knowledge of the statistical performance of single sheet tester (SST) measurements made on grain-oriented electrical steel. These experiments aim at specifying obligatory reference values, measured by the single sheet test method, for the grading of high permeability (P grades) grain-oriented (g.-o.) materials, independently from the Epstein classification as it is practiced today. Besides this, Epstein test measurements have been made in order to gain more up-to-date statistical performance for comparison with the SST statistical characteristics. A few experiments were carried out aiming at improved knowledge on the systematic error performance of the SST, i.e. they were to determine the correlation between the quality of insulation separating laminations in the SST yokes and the measured loss.

General Information

• Status: Published
• Publication Date: 21-May-2017
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.030 - Magnetic materials
• Technical Committee: TC 68 - Magnetic alloys and steels
• Drafting Committee: JWG 1 - TC 68/JWG 1
• Current Stage: PPUB - Publication issued
• Start Date: 07-Jun-2017
• Completion Date: 22-May-2017

Standards Content (Sample)

IEC TR 62981 ®
Edition 1.0 2017-05
TECHNICAL
REPORT
colour
inside
Studies and comparisons of magnetic measurements on grain-oriented
electrical steelsheet determined by the single sheet test method and Epstein
test method
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: [phone]
3, rue de Varembé Fax: [phone]
CH-1211 Geneva 20 [e-mail]
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing 20 000 terms and definitions in
Technical Specifications, Technical Reports and other English and French, with equivalent terms in 16 additional
documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a 65 000 electrotechnical terminology entries in English and
variety of criteria (reference number, text, technical French extracted from the Terms and Definitions clause of
committee,…). It also gives information on projects, replaced IEC publications issued since 2002. Some entries have been
and withdrawn publications. collected from earlier publications of IEC TC 37, 77, 86 and

CISPR.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: [e-mail].
IEC TR 62981 ®
Edition 1.0 2017-05
TECHNICAL
REPORT
colour
inside
Studies and comparisons of magnetic measurements on grain-oriented

electrical steelsheet determined by the single sheet test method and Epstein

test method
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.030 ISBN 978-2-8322-4332-9

– 2 – IEC TR 62981:2017 © IEC 2017
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Background . 7
4.1 Historical background and former concepts of the SST-Epstein relationship . 7
4.2 Establishing reference values for grain-oriented electrical steels determined
by independent SSTs – A new approach to the purpose . 8
5 Preliminary comparisons and experiments . 9
5.1 General . 9
5.2 Comparison of the relative difference δP = (P – P )/P measured
SE SST eps Eps
by steel manufacturers on their own products using own set-ups . 10
5.3 Preliminary comparisons and experiments made by four Chinese
laboratories using six SSTs with stacked yokes . 11
5.4 Necessity of comparing independent SST results . 13
6 International comparison of SST measurements on grain-oriented electrical steel
and accompanying Epstein measurements . 15
6.1 General conditions, samples, participants . 15
6.2 Circulation of the samples and measurement procedure . 16
6.3 Results and analysis of the measured quantities . 17
6.4 Conclusions of the international comparison . 30
7 Summary and conclusions . 31
Bibliography . 32

Figure 1 – Epstein frame and single sheet tester, schematic view, windings partly
omitted . 7
Figure 2 – Relative difference δP = 100 (P – P ) / P versus peak magnetic
SE SST EP EP
polarization J measured by six contributors on samples of their own products . 10
Figure 3 – Contact pattern for the measurement of lamination resistance in the air gap
of SST yokes . 11
Figure 4 – Ratio of the power loss P to that of the SST with the best yokes,
SST
P , versus lamination conductivity factor C of the yokes . 12
SSTopt Y
Figure 5 – Ratio of the power loss at 100 Hz to that at 40 Hz, P /P , at 1,7 T,
100 40
versus lamination conductivity factor C of the yokes . 13
Y
Figure 6 – Relative difference δP = 100(P – P ) / P versus magnetic
SE SST EP EP
polarization . 14
Figure 7 – Relative difference δP = 100(P – P ) / P at 1,7 T determined by
SE SST EP EP
three standard laboratories, IEN, NPL and PTB, on S- and P-type g.-o. sample pairs . 14
Figure 8 – Dispersion of manufacturer’s grain-oriented material production in form of
Epstein samples (PTB 1999) . 15
Figure 9 – Example of scattering of the laboratories’ best estimates around the
reference value (CGO sample No. 2, unweighted average, dash-dotted line) . 18
Figure 10 – Example of scattering of the laboratories’ best estimates around the
reference value (HGO sample No. 4, unweighted average, dash-dotted line) . 19
Figure 11 – Example of scattering of the laboratories’ best estimates around the
reference value (HGO sample No. 5, unweighted average, dash-dotted line) . 19
Figure 12 – Samples No. 1 to No. 5: ratio of SST to Epstein power loss reference
values δP (J ) = (

–

) /

at 50 Hz versus peak polarization . 20
SE p SST Epst Epst
Figure 13 – Overall dispersion (all labs, J values, and samples) of the laboratories'
p
best estimates P of the power loss at 50 Hz around their reference values . 23
i
Figure 14 – Overall dispersion (all labs, J values, and samples) of the laboratories'
p
best estimates S of the apparent power at 50 Hz around their reference values, with
i
and without outliers . 24
Figure 15 – Dispersion around the reference value of the laboratories' best values of
the power loss P measured at 50 Hz by the Epstein and the SST methods at 1,7 T . 25
Figure 16 – Dispersion around the reference value of the laboratories' best values of
the apparent power S measured at 50 Hz by the Epstein and the SST methods at 1,7 T . 26
Figure 17 – Overall dispersion (European metrological laboratories only, all J values
p
and samples) of the laboratories' best estimates P of the power loss at 50 Hz around
i
their reference values, with and without outliers . 27
Figure 18 – Dispersion of the laboratories’ best estimates of SST (a) and Epstein (b)
power loss at 50 Hz . 28
Figure 19 – Dispersion of the laboratories’ best estimates of SST (a) and Epstein (b)
power loss at 50 Hz . 29
Figure 20 – Dispersion of the laboratories’ best estimates, represented by the standard
deviation σ of SST (red) and Epstein (blue) power loss (a) and apparent power (b) at
50 Hz, versus the peak value of the polarization, J , summarizing Figures 18 and 19 . 30
P
Table 1 – Participating laboratories . 16
Table 2 – Circulated grain-oriented electrical steel test samples . 17
Table 3 – Reference values at 50 Hz for the power loss P and the apparent power S . 21
Table 4 – Standard deviations associated with the reference values at 50 Hz for the
power loss P and the apparent power S (Table 3) . 22
Table 5 – Reference values at 50 Hz of the polarization at H = 800 A/m J and
standard deviation of the distribution of the laboratories’ best estimates . 22
Table 6 – Relative standard deviations of 50 Hz power loss P and apparent power S
distributions around their reference values . 27

– 4 – IEC TR 62981:2017 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
STUDIES AND COMPARISONS OF MAGNETIC MEASUREMENTS
ON GRAIN-ORIENTED ELECTRICAL STEELSHEET DETERMINED BY
THE SINGLE SHEET TEST METHOD AND EPSTEIN TEST 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
...