1 Scope
This standard is applicable to grain oriented and non-oriented electrical steel sheet and strip for a.c. measurements of magnetic properties at frequencies up to 400 Hz and for d.c. magnetic measurements.
The object of this standard is to define the general principles and the technical details of the measurement of the magnetic properties of electrical steel sheet and strip by means of an Epstein frame.
The Epstein frame is applicable to test specimens obtained from electrical steel sheets and strips of any grade. The a.c. magnetic characteristics are determined for sinusoidal induced voltages, for specified peak values of magnetic polarization (or of magnetic field strength) and for a specified frequency.
The measurements are to be made at an ambient temperature of (23±5)℃ on test specimens which have first been demagnetized.
Measurements at higher frequencies are to be made in accordance with GB/T 10129.
Note: Throughout this standard, the term "magnetic polarization" is used. In other relevant standards, the terms "magnetic flux density" and “magnetic induction intensity” were used. Under conventional measurement conditions, the difference in the quantity values of these different physical quantities defined above may be negligible.
2 Normative References
The following documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent amendments to (excluding corrections to), or revisions of, any of these publications do not apply. However, the parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards. For undated references, the latest edition of the normative document referred to applies.
GB/T 3102.5-1993 Quantities and Units of Electricity and Magnetism (neq ISO 31-5:1992, Quantities and Units-Part 5: Electricity and Magnetism)
GB/T 10129-1988 Methods of Measurement of Magnetic Properties of Magnetic Steel Sheet and Strip at Medium Frequencies (neq IEC 60404-10: 1988, Magnetic Materials-Part 10: Methods of Measurement of Magnetic Properties of Magnetic Steel Sheet and Strip at Medium Frequencies)
GB/T 19289 Methods of Measurement of Density, Resistivity and Stacking Factor of Electrical Steel Sheet and Strip (GB/T 19289-2003, IEC 60404-13: 1995, Magnetic Materials-Part 13: Methods of Measurement of Density, Resistivity and Stacking Factor of Electrical Steel Sheet and Strip, MOD)
IEC 60404-4: 2000 Magnetic Materials–Part 4: Methods of Measurement of d.c. Magnetic Properties of Magnetically Soft Materials
IEC 60404-3: 1982 Magnetic materials-Methods of Measurement of Specific Total Losses of Magnetic Sheet and Strip by Means of a Single Sheet Tester
Foreword I
1 Scope
2 Normative References
3 General Principles of a.c. Measurements
4 Procedure for the Measurement of the Specific Total Loss
5 Procedure for the Determination of the Peak Value of Magnetic Polarization, r.m.s. Value of Magnetic Field Strength, Peak Value of Magnetic Field Strength and Specific Apparent Power
6 General Principles of d.c. Measurements
7 Procedure for the d.c. Measurement of the Magnetic Polarization
8 Test Report
Appendix A (Informative) Digital Control of the Secondary Induced Voltage Sinusoidal Waveform
Appendix B (Informative) Form Factor Correction
Appendix C (Informative) Effect on the Measurement Result by Means of an Epstein Frame from the Internal Stress Introduced by Cutting the Test Specimen
