Influence of axial mechanical stress on the magnetic properties of non-oriented electrical steel

Axial mechanical stress on electrical steel significantly affects the magnetic properties of electric steel. The magnetizability is reduced and the losses are increased. In electrical machines, axial mechanical stress is induced in different processes of production. The lamination stacks are often compressed by means of axial pressure to create a compact and robust magnetic core. This work focuses on the influence of axial pressure on the rotor lamination stack from a new low cost rotor assembly. A setup is constructed to measure the influence of axial mechanical pressure on the magnetic properties of ring core samples made of electric steel. Extensive measurements at different values of axial mechanical pressure are conducted. From the measured data, an iron loss model is parametrized. The influence of axial mechanical pressure on the hysteresis losses and the eddy current losses is discussed. The identified loss model parameters are applied to the solution of a 2D FEM simulation of the permanent magnet synchronous machine. The influence on the loss characteristics of the machine is studied.