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Description / Abstract:
This test method covers tests for the magnetic properties of
basic flat-rolled magnetic materials at power frequencies (25 to
400 Hz) using a 25-cm Epstein test frame and the 25-cm
double-lap-jointed core. It covers the determination of core loss,
rms exciting power, rms and peak exciting current, and several
types of ac permeability and related properties of flat-rolled
magnetic materials under ac magnetization.
This test method shall be used in conjunction with Practice
A34/A34M.
This test method2 provides a test for core loss and
exciting current at moderate and high magnetic flux densities up to
15 kG [1.5 T] on nonoriented electrical steels and up to 18 kG [1.8
T] on grain-oriented electrical steels.
The frequency range of this test method is normally that of the
commercial power frequencies 50 to 60 Hz. With proper
instrumentation, it is also acceptable for measurements at other
frequencies from 25 to 400 Hz.
This test method also provides procedures for calculating ac
impedance permeability from measured values of rms exciting current
and for ac peak permeability from measured peak values of total
exciting currents at magnetic field strengths up to about 150 Oe
[12 000 A/m].
Explanation of symbols and abbreviated definitions appear in the
text of this test method. The official symbols and definitions are
listed in Terminology A340.
The values and equations stated in customary (cgs-emu and
inch-pound) or SI units are to be regarded separately as standard.
Within this standard, SI units are shown in brackets except for the
sections concerning calculations where there are separate sections
for the respective unit systems. The values stated in each system
may not be exact equivalents; therefore, each system shall be used
independently of the other. Combining values from the two systems
may result in nonconformance with this standard.
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.
2 Burgwin, S. L., "Measurement of Core Loss and A-C
Permeability with the 25-cm Epstein Frame," Proceedings,
American Society for Testing and Materials, ASTEA, Vol 41, 1941, p.
779.