Influence of Interlocking on Magnetic Properties of Electrical Steel Laminations

Abstract

Interlocking is a suitable method to fix iron cores made of electrical steel sheets along the stack direction. However, this will increase iron loss of the core and, as a result, lower the efficiency and power density of electrical machines. In this paper, the influence of interlocking on the magnetic properties of ring cores is studied and evaluated by measurements. A linear increase of the inverse of magnetic field and iron loss with increasing number of interlocks shows that the influence of interlocking is local. This behavior coincides with the proposed model. Interlaminar eddy currents have no serious impact on the iron-loss properties. Averaged magnetic properties of the magnetically deteriorated regions are calculated according to the magnetic model. These data will be useful for accurate finite-element method calculations of iron losses in electrical machines.