Effects of Uniaxial Stress Along Different Directions on Alternating Magnetic Properties of Silicon Steel Sheets

Extensive research has shown that silicon steel sheets in electrical machines and power transformers are usually working under compressive or tensile stress, which affects both magnetic properties of silicon steel sheets and performance of electromagnetic devices. In this article, a magnetic property measurement system considering the stress effect has been developed and constructed based on the large cross-shaped single-sheet tester (LCSST). The uniformity of the stress distribution for LCSST is verified by the finite- element method. The B-H magnetic property of a specimen of non-oriented silicon steel 50JN470 in the direction of applied stress is measured by the proposed LCSST, and the results are in good agreement with those measured by the rectangle single-sheet tester (RSST) made by the Brockhaus Company. The RSST, however, cannot measure the effects of uniaxial stress on the magnetic properties. This article presents and analyzes the extensive experimental results of magnetic properties with uniaxial stress applied along both transverse and rolling directions ranging from 7 MPa compressive stress to 7 MPa tensile stress.