IS 16586 : 2024/IEC 60404-16 : 2018 Magnetic Materials - Methods of Measurement of the Magnetic Properties of Fe-Based Amorphous Strip by Means of a Single Sheet Tester
| ICS 17.220.20; 29.030 | MTD 04 |
NATIONAL FOREWORD
This Indian Standard (First Revision) which is identical to IEC 60404-16 : 2018 'Magnetic materials - Part 16: Methods of measurement of the magnetic properties of Fe-based amorphous strip by means of a single sheet tester' issued by the International Electrotechnical Commission (IEC) was adopted by the Bureau of Indian Standards on the recommendation of the Wrought Steel Products Sectional Committee and approval of the Metallurgical Engineering Division Council.
This standard was originally published in 2016. This revision has been undertaken to align it with the latest version of IEC 60404-8-16 : 2018 under dual numbering system to harmonize it with the latest developments that have taken place at international level.
After appropriate heat treatment, the strip exhibits quite a lower value of specific total loss in comparison to grain-oriented electrical steel strip. It is associated with low hysteresis loss due to low magnetic anisotropy and low eddy current loss due to a high resistivity and a thin thickness. However, it may deteriorate significantly by applying stress on the strip due to high magnetostriction and low magnetic anisotropy of the material. The strip is usually supplied without any insulating coating. Consequently, an effect of inter-laminar eddy-current loss may increase the specific total loss values when the strip is laminated tightly into toroidal cores. Moreover, even if construction stresses induced by bending the strip into toroidal core could be removed by heat treatments, a small change in the diameter of test specimen cases unexpected stress in the material and then deteriorated magnetic properties may be obtained.
Therefore, methods of measurement of the magnetic properties of Fe-based amorphous strip by means of a single sheet tester are required.
Several attentions are necessary for the single sheet tester. Insignificant stress applied on the material could cause deterioration of magnetic properties of the material. Effects of the flux closure yoke, an introducing on stress into the material by a weight of upper yoke could be severe for the material. Therefore, a vertical single yoke is suitable to prevent the effects caused by an upper yoke. Moreover, deformation of the test specimen near the pole faces may introduce stress into the material. The H coil method is essential to avoid detecting the deteriorated properties of the test specimen beneath the pole faces. The material has lower magnetic anisotropy due to lack of crystalline anisotropy and its permeability is quite high, so the single sheet tester is recommended to be equipped a magnetic shield to prevent unexpected magnetization by the geomagnetic field.
Thin thickness, higher permeability and low total loss of the Fe-based amorphous strip bring weak output signals from the secondary coil, the H coil and the shunt resister to measure the magnetizing current of the SST apparatus. These signals shall be amplitude using low noise pre-amplifiers before the data acquisition devices. The digital sampling method is recommended to measure these weak signals. Observations of hysteresis loops are necessary to check the quality of measurements.
The text of IEC standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions and terminologies are however not identical to those used in Indian Standards. Attention is particularly drawn to the following:
a) Wherever the words 'International Standard' appear referring to this standard, they should be read as 'Indian Standard'; and
b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practice is to use a point (.) as the decimal marker.