Experimental study on the impact of the number of laminas on the dynamics behavior of an electric machine stator

Abstract

Electromagnetic forces applied on the stator of an electric machine highly contribute to its overall acoustic noise. Made of steel, the stator core is also considered as the main transfer path contributor to the electrical machine mass and stiffness. Moreover it is composed of axially stacked steel laminations to reduce eddy current losses during the electric motor operation. Those hundreds of laminas do not behave like solid steel which makes the modelling process non-trivial. A systematic approach is then followed in this paper, which starts from modal testing of a single sheet and progressively increasing the number of laminas in a stack until the corresponding length of a full stator is reached. Therefore the effects of the inter-laminar interference on the structural behavior are investigated for the different number of laminas in a stack. Specific nonlinearities checks are also carried out to characterize the different structures. The preliminary results show promising linear behavior for radial-type excitations whilst axial components present some possibly high nonlinearities.