An Induction Motor Stator Core Fault Model Based on Stator Negative Sequence Current

Abstract

An on-line method is proposed in this work to detect induction motor stator core fault by using stator negative sequence current. According to the existing abc coordinate model, a new equivalent circuit is obtained. In this circuit, the stator core loss each phase in normal state is modeled as core loss resistance symmetrically distributed among the three phases. The stator core loss is increased and is asymmetrically distributed among the three phases when a stator fault happens. The positive, negative and zero sequence equivalent circuits are drawn by a series of analysis of the circuit put forward above. It is demonstrated that there is a good correlation between stator core fault severity and the magnitude of the negative sequence current.