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.

Note 1-These test methods have been applied only at the commercial power frequencies, 50 and 60 Hz, but with proper instrumentation and application of the principles of testing and calibration embodied in the test methods, they are believed to be adaptable to testing at frequencies ranging from 25 to 400 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:

Test Method 1-Sections 6 to 12 Test Method 2-Sections 13 to 19