Electromagnetic Forces Acting Between the Stator and Eccentric Cage Rotor;Doctoral thesis

摘要

Electromagnetic forces act between the rotor and stator when the rotor is performing eccentric motions with respect to stator. The aim of this research was to study the characteristics of the forces and develop the tools to calculate these forces accurately and as quickly as possible. A new method, called the impulse method, is developed into the finite element analysis of the electromagnetic field to calculate the forces for a wide whirling frequency range by one simulation. The idea of the impulse method is to move the rotor from its central position for a short period of time. This displacement excitation disturbs the magnetic field and, by doing this, produces forces between the rotor and stator. Using spectral analysis techniques, the frequency response function of the forces is calculated using the excitation and response signals. The impulse method is based on the assumption of a spatial linearity of the force.