Intercomparison of a.c. magnetic measurements on electrical sheet steels using a single sheet tester
The object of this intercomparison was to determine the level of agreement between major national and industrial metrology laboratories specialising in the measurement of the magnetic properties of various qualities of steel used in the construction of electrical machines and transformer cores. Measurements of specific total power loss, specific apparent power and relative magnetic permeability were made at a frequency of 50 Hz on 20 sheets, each 500 x 500 mm, using a single sheet tester in accordance with IEC Standard 404, Part 3, 1982. For commercial grading purposes, there was found to be good agreement between 5 out of the 6 participants for specific total power loss measurements and agreement between all participants for permeability measurements. For specific apparent power measurements it is recommended that the reproducibility is increased to 5% as the magnetic circuit conditions vary from user to user. In addition, the intercomparison has shown that a single value of effective magnetic path length of 450 mm could be adopted for the IEC single sheet tester. This value gives the best compromise when comparing results from the sheet tester with measurements in the previously used Epstein frame.
Bibliographic Reference: EUR 12377 EN (1989) MF, 91 pp., ECU 4, blow-up copy ECU 12.50
Record Number: 198911174 / Last updated on: 1994-12-01
Original language: en
Available languages: en