PD IEC/TR 62981:2017

FOREWORD
1 Scope
2 Normative references
3 Terms and definitions
4 Background
5 Preliminary comparisons and experiments
6 International comparison of SST measurements
  on grain-oriented electrical steel and accompanying
  Epstein measurements
7 Summary and conclusions
Bibliography

Gives 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.

This document, 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.

There are various designations for \'non-oriented electrical sheet steel\' and for \'grain-oriented electrical sheet steel\' in use, for example in the IEC 60404 classification and specification standards, and there are also abbreviations like CGOS (for conventional grain-oriented steel) often used in industry. In this report, the following designations and abbreviations are used:

• electrical steel as generic term;

• n.-o- electrical steel and g.-o. electrical steel as generic terms for these two types;

• S-type electrical streel or c. g.-o. electrical steel for \'conventional grain-oriented electrical steel\';

• P-type g.-o. electrical steel or high-permeability g.-o. electrical steel;

• DR g.-o. electrical steel for \'domain refined grain-oriented electrical steel\';

• where two terms are used, it can depend on the context;

• \'electrical steel\' can be replaced with \'material\', depending on the context.