PRECISE MAGNETIC MEASUREMENTS ON ELECTRICAL SHEET STEELS
The object of this intercomparison was for five national laboratories to determine the specific total power loss and the a.c. permeability on various qualities of sheet steel, used in the construction of electrical machines and transformer cores. The electromagnetic losses of the steels varied from 7.0 W/kg for the non oriented low silicon steel to 0.8 W/kg for the high B grain samples and toroidal cores at the frequencies of 25, 50 and 75 Hz and at magnetic flux densities at 1.5, 1.7 and 1.8T. The general measurement principles of the methods used were in accordance with the IEC Standard 404 PART 2 (1978), EURONORM 118-75 and BS601 PART 5. The a.c. permeability results agreed within 1.2% between the laboratories. After some demagnetization problems were overcome in one participating laboratory, the maximum deviation of the obtained results were less than 1% for all laboratories on the Epstein frame samples at the "grading conditions" (50 Hz, 1.5T). The deviation of results for the "non grading conditions" was up to 4%. The variation in the results on the toroidal ring cores was about 2% for the "grading conditions" and up to 4% for the "non grading conditions". This was unexpectedly high, so that some further work needs to be done to improve the situation.
Bibliographic Reference: EUR 10233 EN (1985) MF, 43 P., BFR 150, BLOW-UP COPY BFR 215, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989124072200 / Last updated on: 1987-01-01
Available languages: en