PD IEC TR 62581 pdf download Electrical steel — Methods of measurement of the magnetostriction characteristics by means of single sheet and Epstein test specimens
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 1 00 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.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60050-1 21 , International Electrotechnical Vocabulary – Part 121: Electromagnetism
IEC 60050-221 , International Electrotechnical Vocabulary – Chapter 221: Magnetic materials and components
IEC 60404-2, Magnetic materials – Part 2: Methods of measurement of the magnetic properties of electrical steel sheet and strip by means of an Epstein frame
IEC 60404-3:1 992, Magnetic materials – Part 3: Methods of measurement of the magnetic properties of electrical steel strip and sheet by means of a single sheet tester Amendment 1 (2002)
Amendment 2 (2009)
IEC 61 672-1 , Electroacoustics – Sound level meters – Part 1: Specifications
3 Terms and definitions
For the purpose of this document, the definitions of the principal terms relating to magnetic properties given in IEC 60050-1 21 and IEC 60050-221 apply, as well as the following terms and definitions:
hysteresis loop of the strain measured in the direction of applied field versus the magnetic polarization for a period of an alternating magnetization
net strain measured in the direction of applied field from the zero magnetic polarization to a given magnetic polarization
amplitude of the strain measured in the direction of the applied field under alternating magnetization
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
Measurement systems for magnetostriction are shown in Figure 1 and Figure 2. A block diagram of the measurement system is shown in Figure 3.
The test specimen comprises a sample of electrical steel sheet and is placed inside two windings:
– an external primary winding;
– an interior secondary winding.