ASTM A804/A804M-99

1.1 These test methods cover the determination of specific core loss and peak permeability of single layers of sheet-type specimens tested with normal excitation at a frequency of 50 or 60 Hz.

1.2 These test methods employ calibration procedures that provide correlation with the 25-cm [250-mm] Epstein test.

1.3 The range of test inductions is governed by the properties of the test specimen and by the available instruments and other equipment components. Normally, nonoriented electrical steels can be tested over a range from 8 to 16 kG [0.8 to 1.6 T] for core loss. For oriented electrical steels, the normal range extends to 18 kG [1.8 T]. Maximum inductions in peak permeability testing are limited principally by heating of the magnetizing winding and tests are limited normally to a maximum a-c magnetizing force of about 150 Oe [12 000 A/m].

1.4 These test methods cover two alternative procedures as follows: