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1.1 This guide covers procedures for interpreting the specific core loss and peak permeability determined using small single-sheet test systems. It is limited to single-sheet test systems that require a test specimen or coupon be cut from the material being tested and are designed such that the entire width of that test specimen is magnetized during testing.
1.2 This guide is primarily intended for measurements of the magnetic properties of flat-rolled electrical steels at frequencies of 50 Hz or 60 Hz under sinusoidal flux conditions.
1.3 This guide includes procedures to provide correlation with the 25-cm Epstein test method (Test Method A 343/A 343M).
1.4 The range of magnetic flux densities is governed by the properties of the test specimens and the instruments and test power source. Nonoriented electrical steels may be tested at magnetic flux densities up to about 16-kG [1.6T] for core loss. The maximum magnetic field strength for peak permeability testing is limited by the current carrying capacity of the magnetizing winding and the test power source. Single sheet testers are typically capable of testing at magnetic field strengths up to 50 Oe [4000 A/m] or more.
1.5 Within this guide, a small single sheet tester (small SST) is defined as a magnetic tester designed to test flat, rectangular sheet-type specimens. Typical specimens for these testers are square (or nearly so). The design of the small SST test fixture may be small enough to accommodate specimens about 5 by 5 cm or may be large enough to accommodate specimens about 36 by 36 cm. Specimens for a particular SST must be appropriate for the particular test fixture.
1.6 This guide covers two alternative test methods: Method 1 and Method 2.
1.6.1 Method 1 is an extension of Method 1 of Test Method A 804/A 804M, which describes a test fixture having two windings that encircle the test specimen and two low-reluctance, low-core loss ferromagnetic yokes that serve as flux return paths. The dimensions of the test fixture for Method 1 are not fixed but rather may be designed and built for any nominal specimen dimension within the limits given in . The power loss in this case is determined by measuring the average value of the product of primary current and induced secondary voltage.
1.6.2 Method 2 covers the use of a small single sheet tester, which employs a magnetizing winding, a magnetic flux sensing winding, and a magnetic field strength detector. The power loss in this case is determined by measuring the average value of the product of induced secondary voltage and magnetic field strength.
1.6.3 The calibration method described in the Annex of this guide applies to both test methods.
1.7 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. 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 requirements prior to use.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
A340 Terminology of Symbols and Definitions Relating to Magnetic Testing
A343/A343M Test Method for Alternating-Current Magnetic Properties of Materials at Power Frequencies Using Wattmeter-Ammeter-Voltmeter Method and 25-cm Epstein Test Frame
A677 Specification for Nonoriented Electrical Steel Fully Processed Types
A683/A683M Specification for Nonoriented Electrical Steel, Semiprocessed Types
A726 Specification for Cold-Rolled Magnetic Lamination Quality Steel, Semiprocessed Types
A804/A804M Test Methods for Alternating-Current Magnetic Properties of Materials at Power Frequencies Using Sheet-Type Test Specimens
A840/A840M Specification for Fully Processed Magnetic Lamination Steel
ICS Number Code 29.030 (Magnetic materials)
UNSPSC Code 31380000(Magnets and magnetic materials)