Transformer Laminations

Amerace uses only grain oriented silicon steel flat laminations (E & I configurations) conforming to:

ASTM A876/A876M-98 “Standard Specification for Flat-Rolled, Grain-Oriented, Silicon-Iron, Electrical Steel, Fully Processed Types”

As a designer and manufacturer of transformers, Amerace is vitally interested in the magnetic and electrical properties of the laminations we use. The base magnetic steel properties are tested, but one of the problems in testing laminations such as E & I is that the manufacturing process (stamping) may change the base steel properties. To overcome these variations and provide reliable comparisons our vendor uses the standard Epstein frame test described in the following two standards:

ASTM A34/A34M-96 “Standard Practice for Sampling and Procurement Testing of Magnetic Materials”

ASTM A343-97 “Standard Test Method for Alternating-Current Magnetic Properties of Materials at Power Frequencies Using Wattmeter-Ammeter-Voltmeter Method and 25-cm Epstein Test Frame”

This test is designed to eliminate the effect of joints, non-sinusoidal waveforms, and non uniform flux distribution. As a result, the test is a fundamental description of the base steel used, rather than of an individual lamination stack, and is a reliable guide to the relative performance of any assembled unit.