ASTM A 598 : 1992 : R1997

1.1 This test method covers the determination of the magnetic performance of fully processed cores for magnetic amplifier-type applications.

1.2 Tests may be conducted at excitation frequencies of 60, 400, 1600 Hz, or higher frequencies.

1.3 Permissible core sizes for this test method are limited only by the available power supplies and the range and sensitivity of the instrumentation.

1.4 At specified values of full-wave sinusoidal-current excitation, Hmax , this test method provides procedures of determining the corresponding value of maximum induction, Bmax .

1.5 At specified values of half-wave sinusoidal-current excitation, this test method provides procedures for determining the residual induction, Br .

1.6 At increased specified values of half-wave sinusoidal-current excitation, this test method provides procedures for determining the dc reverse biasing magnetizing force, H1 , required to reset the induction in the core material past Br to a value where the total induction change, [delta] B1 , becomes approximately one third of the induction change, 2 Bp . It also provides procedures for determining the additional dc reset magnetizing force, [delta] , which, combined with H1 , is the value required to reset the induction in the core material past Br to a value where the total induction change, [delta] B2 , becomes approximately two thirds of the induction change 2 Bp .

1.7 This test method specifies procedures for determining core gain from the corresponding biasing and induction changes, [delta] and [delta] .

1.8 This test method covers test procedures and requirements for evaluation of finished cores which are to be used in magnetic-amplifier-type applications. It is not a test for basic-material magnetic properties.

1.9 This test method shall be used in conjunction with Practice A34.

1.10 Explanations of symbols and abbreviated definitions appear in the text of this test method. The official symbols and definitions are listed in Terminology A340. This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

1.11 The preferred units and corresponding values appearing in this standard are customary (cgs-emu) units. SI units are indicated in parentheses. When necessary, separate equations, conversion factors, and inclusions for SI values are given in the text or tables.