ASTM A697-98

1.1 This test method covers the determination of several ac magnetic properties of laminated cores made from flat-rolled magnetic materials.

1.2 This test method covers test equipment and procedures for the determination of impedance permeability and exciting power, from voltage and current measurements, and core loss from wattmeter measurements. These tests are made under conditions of sinusoidal flux.

1.3 This test method covers tests for two general categories (1 and 2) of cores based on size and application.

1.4 Tests are provided for power and control size cores (Category 1) operating at inductions of 10 to 15 kG [1.0 to

1.5 T] and at frequencies of 50, 60, and 400 Hz.

1.5 Procedures and tests are provided for coupling and matching type transformer cores (Category 2) over the range of inductions from 100 G [0.01 T] or lower to 10 kG [1.0 T] and above at 50 to 60 Hz or above when covered by suitable procurement specifications.

1.6 This test method also covers tests for core loss and ac impedance permeability under incremental test conditions (ac magnetization superimposed on dc magnetization) for the above core types and at inductions up to those that cause the ac exciting current to become excessively distorted or to reach values that exceed the limits of the individual test-equipment components.

1.7 This test method shall be used in conjunction with Practice A34 and Terminology A340. It depends upon these designated documents and a related reference test manual for detailed information which will not be repeated in this test method.

1.8 The preferred units in this standard are (cgs-emu and inch-pound) units. Values in SI units are indicated in brackets or conversion factors are provided. Derivations of separate equations for SI units are provided as necessary.

1.9 This standard does not purport to address all of the safety concerns, 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.