Transient Voltage Distribution in Induction Motor Stator Windings Using Finite Elements Method

Overvoltages caused by steep-fronted surges can lead to induction motors main and interturn insulations to failure. The knowledge of the voltage distribution in induction motor windings due to voltage surges are of big importance for the motor design. In this context this work aims at verifying the transient voltage distribution in the motor coils when stator windings are subjected to steep-fronted voltages. The paper presents results of numerical simulations of transient voltages in stator windings of a large induction motor with form wound coils using a model that combines distributed and lumped parameters using the Finite Elements Method (FEM). Firstly, the influence of the rotor in the model is studied. In sequence, overvoltages in motor coils are simulated for different surge rise times.