Effects of stator core welding on an induction machine – Measurements and modeling

There is a growing interest towards increasing the efficiency of electrical machines to reduce the ecological footprint. The efficiency of an electrical machine is closely related to the understanding and accurate estimation of the associated losses. One loss component is related to the welding of the electrical steel sheets as a part of manufacturing. This paper studies the effect of the core welding on a typical industrial induction motor. The effect of core welding on the magnetic permeability and core losses is first analyzed with the help of magnetic measurements on the unwelded and welded ring cores assembled from the stator sheets. Further, the derived material parameters are applied in finite element analysis of the induction machine and the effect of welding on the machine performance parameters is analyzed. It was observed that stator core losses increased about 10% due to the welding effect. A mock-up prototype is then manufactured to measure the stator core losses which follow the simulated values closely.