IEC TR 62581:2010

Electrical steel - Methods of measurement of the magnetostriction characteristics by means of single sheet and Epstein test specimens

IEC/TR 62581:2010(E) describes the general principles and technical details of the measurement of the magnetostriction of single sheet specimens preferably 500 mm long and 100 mm wide and Epstein strip specimens, specified in IEC 60404-2, of electrical steel by means of optical sensors and accelerometers. These methods are applicable to test specimens obtained from electrical steel sheets and strips of any grade. The characteristics of magnetostriction are determined for a sinusoidal induced voltage, for specified peak values of magnetic polarization and for a specified frequency. The measurements are made at an ambient temperature of 23 °C +/- 5 °C on test specimens which have first been demagnetized.

General Information

• Status: Published
• Publication Date: 05-Aug-2010
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.030 - Magnetic materials
• Technical Committee: TC 68 - Magnetic alloys and steels
• Drafting Committee: WG 2 - TC 68/WG 2
• Current Stage: PPUB - Publication issued
• Start Date: 31-Oct-2010
• Completion Date: 06-Aug-2010

Standards Content (Sample)

IEC/TR 62581 ®
Edition 1.0 2010-08
TECHNICAL
REPORT
Electrical steel – Methods of measurement of the magnetostriction
characteristics by means of single sheet and Epstein test specimens

IEC/TR 62581:2010(E)
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IEC/TR 62581 ®
Edition 1.0 2010-08
TECHNICAL
REPORT
Electrical steel – Methods of measurement of the magnetostriction
characteristics by means of single sheet and Epstein test specimens

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
X
ICS 29.030 ISBN 978-2-88912-101-4
– 2 – TR 62581 © IEC:2010(E)
CONTENTS
FOREWORD.5
INTRODUCTION.7
1 Scope.8
2 Normative references .8
3 Terms and definitions .8
4 Method of measurement of the magnetostriction characteristics of electrical steel
sheets under applied stress by means of a single sheet tester.9
4.1 Principle of the method.9
4.2 Test specimen.11
4.3 Yokes.12
4.4 Windings .13
4.5 Air flux compensation .14
4.6 Power supply.14
4.7 Optical sensor .14
4.8 Stressing device.15
4.9 Data acquisitions.15
4.10 Data processing .16
4.11 Preparation for measurement .16
4.12 Adjustment of power supply.17
4.13 Measurement .17
4.14 Determination of the butterfly loop.20
4.15 Determinations of the zero-to-peak and peak-to-peak values.20
4.16 Reproducibility .20
5 Examples of the measurement systems.20
5.1 Single sheet tester .20
5.2 Epstein strip tester .25
6 Examples of measurement .26
6.1 Magnetostriction without external stress .26
6.2 Magnetostriction under applied stress .27
6.3 Variation of magnetostriction with coating tension .30
6.4 Factors affecting precision and reproducibility .34
6.4.1 General .34
6.4.2 Overlap length between test specimen and yoke .34
6.4.3 The averaging effect on environmental noise.34
6.4.4 Gap between test specimen and yoke.34
6.4.5 Resetting the test specimen.35
7 Methods of evaluation of the magnetostriction behaviour.36
7.1 Relationship between magnetostriction and magnetic domain structure.36
7.2 A simple model of magnetostriction behaviour.37
Annex A (informative) Requirements concerning the prevention of out-of-plane
deformations.40
Annex B (informative) Application of retained stress model to measured stress shifts .42
Annex C (informative) A-weighted magnetostriction characteristics .45
Bibliography.48

TR 62581 © IEC:2010(E) – 3 –
Figure 1 – Measurement systems for magnetostriction.9
Figure 2 – Section of the test frame; A-A’ in Figure 1 .10
Figure 3 – Block diagram of the measurement system .10
Figure 4 – Frames with various types of yoke .13
Figure 5 – Base length l for various types of frame (see Figure 4) .18
Figure 6 – Butterfly loop and determinations of zero-to-peak and peak-to-peak values of
magnetostriction .20
Figure 7 – Measurement system using a Michelson interferometer; differential
measurement [1].21
Figure 8 – Measurement system using a laser Doppler vibrometer; differential
measurement [2], [3], [17] .21
Figure 9 – Measurement system using a laser Doppler vibrometer; differential
measurement [4],[5].23
Figure 10 – Measurement system using a laser displacement meter; single point
measurement [7].23
Figure 11 – Measurement system using a laser displacement meter; single point
measurement [6].24
Figure 12 – Measurement system using a laser Doppler vibrometer; single point
measurement [8].24
Figure 13 – Schematic diagram of an automated system using accelerometer sensors [12] .25
Figure 14 – Example of measured results for high permeability grain-oriented electrical
steel of 0,3 mm thick sheet; at 1,3 T, 1,5 T, 1,7 T, 1,8 T and 1,9 T, 50 Hz [2].29
Figure 15 – Increase in magnetostriction with compressive stress in the rolling direction;
at 1,5 T, 1,7 T and 1,9 T, 50 Hz [2] .29
Figure 16 – Typical zero-to-peak magnetostriction versus applied stress for high
permeability grain-oriented electrical steel sheet at 1,5 T, 50 Hz [12].29
Figure 17 – Stress sensitivity of magnetostriction and permeability in a typical fully
processed sample [12].30
Figure 18 – Typical harmonics of magnetostriction versus applied stress for
conventional grain-oriented electrical steel at 1,5 T, 50 Hz [12] .30
Figure 19 – Variation of maximum magnetostriction under compressive stress in high
permeability grain-oriented electrical steel at 1,5 T, 50 Hz [20] .31
Figure 20 – Variation of maximum magnetostriction under compressive stress in
conventional grain-oriented electrical steel at 1,5 T, 50 Hz [20] .31
Figure 21 – Magnetostriction versus stress characteristics in the rolling direction of
conventional grain-oriented electrical steel before and after coating removal at 1,5 T,
50 Hz [20] .31
Figure 22 – Magnetostriction versus stress characteristics in the transverse direction of
conventional grain-oriented electrical steel before and after coating removal at 1,5 T,
50 Hz [20] .31
Figure 23 – Magnetostriction versus peak value of magnetic polarization for high
permeability 0,30 mm grain-oriented electrical steel sheets with three different coatings;
external stress was not applied [17] .33
Figure 24 – Magnetostriction versus peak value of magnetic polarization for high
permeability 0,30 mm grain-oriented electrical steel sheets with three different coatings;
external compressive stress of 3 MPa was applied in the rolling direction [17] .33
Figure 25 – Effects of overlap length on the reproducibility of measurement [4] .34
Figure 26 – Effect of averaging number on reduction of the error caused by the
environmental noise [5].34

– 4 – TR 62581 © IEC:2010(E)
Figure 27 – Effect of gap between the test specimen and the yoke on the reproducibility
of measurement; the test specimen was reset at every measurement [5] .35
Figure 28 – Effect of reset of the test specimen on the reproducibility of measurement;
the gap distance was 1,2 mm [5] .35
Figure 29 – Magnetic domain patterns on a grain-oriented electrical steel sheet [2] .36
Figure 30 – Schematic diagrams for explanation of magnetic domains and
magnetostriction [2],[17] .36
Figure 31 – Separation of the different features of peak-to-peak magnetostriction
according to the proposed model [27] .38
Figure 32 – Measured peak-to-peak and zero-to-peak magnetostriction of a grain-oriented
electrical steel sheet with fitted curves according to the proposed model [27] .38
Figure 33 – Effect of coating tension on J − λ curves; λ is the normalized value
m sp sp
of zero-to-peak mag
...