Voltages in the Shaft of the Induction Motor in 3D FEM Formulation

A 3D model reflecting entire internal structure of the asynchronous machine using finite elements method, has been presented here. Nodal finite elements have been used to approximate scalar potential and edge finite elements to approximate vector magnetic potential. This model includes both the skew of the rotor bars as well cross current flowing through the rotor iron laminates. The three-phase stator winding is supplied with four-lead mains voltage. The axial flux was calculated by integration of the vector potential around the shaft of the machine. Making isolation between I a mine worse in the area of tooth stator, was leading to the voltage in the rotor shaft, this voltage was used for diagnostics. Plots were calculated following the switching on the machine at various speeds. Bar as well as ring fractures were simulated. The simulation results have been confirmed by the theoretical anticipations.