Practical investigations on cobalt-iron laminations for electrical machines

The adoption of high-performance soft magnetic material can be considered a possible way to respect the challenging design specifications for aerospace and automotive electrical machines. This paper presents an accurate noninvasive investigation of magnetic and energetic properties of cobalt-iron stator cores. In particular, the focus lies on the annealing processes aimed to maximize the magnetic saturation and the mechanical strength. Three cobalt-iron stator core samples coming from different annealing processes have been analyzed, both from the BH characteristics and losses viewpoints. Stator slot effects on the magnetic measurements have been investigated by finite-element method. A fringing effect correction factor to be applied on the measured BH curves is as well reported. In order to complete the experimental campaign analysis, micrographic analysis of the material structure is presented, as well as the iron losses separation coefficients