BSI PD IEC/TR 62581:2010
$198.66
Electrical steel. Methods of measurement of the magnetostriction characteristics by means of single sheet and Epstein test specimens
| Published By | Publication Date | Number of Pages |
| BSI | 2010 | 54 |
This technical report 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.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 4 | CONTENTS |
| 7 | FOREWORD |
| 9 | INTRODUCTION |
| 10 | 1 Scope 2 Normative references 3 Terms and definitions |
| 11 | 4 Method of measurement of the magnetostriction characteristics of electrical steel sheets under applied stress by means of a single sheet tester 4.1 Principle of the method Figures Figure 1 – Measurement systems for magnetostriction |
| 12 | Figure 2 – Section of the test frame; A-A’ in Figure 1 Figure 3 – Block diagram of the measurement system |
| 13 | 4.2 Test specimen |
| 14 | 4.3 Yokes |
| 15 | 4.4 Windings Figure 4 – Frames with various types of yoke |
| 16 | 4.5 Air flux compensation 4.6 Power supply 4.7 Optical sensor |
| 17 | 4.8 Stressing device 4.9 Data acquisitions |
| 18 | 4.10 Data processing 4.11 Preparation for measurement |
| 19 | 4.12 Adjustment of power supply 4.13 Measurement |
| 20 | Figure 5 – Base length for various types of frame (see Figure 4) |
| 22 | 4.14 Determination of the butterfly loop 4.15 Determinations of the zero-to-peak and peak-to-peak values 4.16 Reproducibility 5 Examples of the measurement systems 5.1 Single sheet tester Figure 6 – Butterfly loop and determinations of zero-to-peak and peak-to-peak values of magnetostriction |
| 23 | Figure 7 – Measurement system using a Michelson interferometer; differential measurement [1] Figure 8 – Measurement system using a laser Doppler vibrometer; differential measurement [2], [3], [17] |
| 25 | Figure 9 – Measurement system using a laser Doppler vibrometer; differential measurement [4],[5] Figure 10 – Measurement system using a laser displacement meter; single point measurement [7] |
| 26 | Figure 11 – Measurement system using a laser displacement meter; single point measurement [6] Figure 12 – Measurement system using a laser Doppler vibrometer; single point measurement [8] |
| 27 | 5.2 Epstein strip tester Figure 13 – Schematic diagram of an automated system using accelerometer sensors [12] |
| 28 | 6 Examples of measurement 6.1 Magnetostriction without external stress |
| 29 | 6.2 Magnetostriction under applied stress |
| 31 | 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] 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] 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] |
| 32 | 6.3 Variation of magnetostriction with coating tension Figure 17 – Stress sensitivity of magnetostriction and permeability in a typical fully processed sample [12] Figure 18 – Typical harmonics of magnetostriction versus applied stress for conventional grain-oriented electrical steel at 1,5 T, 50 Hz [12] |
| 33 | Figure 19 – Variation of maximum magnetostriction under compressive stress in high permeability grain-oriented electrical steel at 1,5 T, 50 Hz [20] Figure 20 – Variation of maximum magnetostriction under compressive stress in conventional grain-oriented electrical steel at 1,5 T, 50 Hz [20] 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] 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] |
| 35 | 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] 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] |
| 36 | 6.4 Factors affecting precision and reproducibility Figure 25 – Effects of overlap length on the reproducibility of measurement [4] Figure 26 – Effect of averaging number on reduction of the error caused by the environmental noise [5] |
| 37 | 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] Figure 28 – Effect of reset of the test specimen on the reproducibility of measurement; the gap distance was 1,2 mm [5] |
| 38 | 7 Methods of evaluation of the magnetostriction behaviour 7.1 Relationship between magnetostriction and magnetic domain structure Figure 29 – Magnetic domain patterns on a grain-oriented electrical steel sheet [2] Figure 30 – Schematic diagrams for explanation of magnetic domains and magnetostriction [2],[17] |
| 39 | 7.2 A simple model of magnetostriction behaviour |
| 40 | Figure 31 – Separation of the different features of peak-to-peak magnetostriction according to the proposed model [27] 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] |
| 41 | Figure 33 – Effect of coating tension on Jm – λsp curves; λsp is the normalized value of zero-to-peak magnetostriction to the value at saturation polarization [17] Figure 34 – Effect of laser irradiation on Jm – λsp curves; λsp is the normalized value of zero-to-peak magnetostriction to the value at saturation polarization [17] |
| 42 | Annex A (informative) Requirements concerning the prevention of out-of-plane deformations |
| 43 | Figure A.1 – Schematic diagram of out-of-plane deformation of test specimen (length lm) with radius r Figure A.2 – Errors in length change of the test specimen Δl/lm versus out-of-plane deformation distance Δd |
| 44 | Annex B (informative) Application of retained stress model to measured stress shifts |
| 45 | Table B.1 – Measured stress shifts for two stage coating removal |
| 46 | Figure B.1 – Variation of coating stress with coating thickness for forsterite and phosphate coating [20] |
| 47 | Annex C (informative) A-weighted magnetostriction characteristics Figure C.1 – Frequency response of the acoustic A-weighting filter, specified in IEC 61672-1 |
| 49 | Figure C.2 – A-weighted magnetostriction acceleration levels of CGO-0,30 mm and HGO-0,30 mm materials |
| 50 | Bibliography |
