A 3D-coil model for bearing current analysis of inverter-fed drives

In this paper a study of a 3D-coil model which is suitable for the analysis of bearing currents in converter-fed induction motors is presented. The coil model consists of one slot surrounded by a part of the stator yoke. The thin lamination of the yoke is scaled up spatially in the direction of current propagation in the slot for the simulations. The excitation is carried out by means of a sinusoidal current at different frequencies. In a second set of simulations, a voltage surge is considered as the excitation signal. The bearing current is evaluated in frequency domain as well as in time domain.