The investigation of induction motors under abnormal condition

Abstract

This paper aims to present the negative effects of the unbalanced sinusoidal voltage on the operating of induction motors; this voltage quality anomaly could cause serious problems such as highly unbalanced currents on the stator, mechanical oscillations and interference with control electronics. In this research the detection of this unhealthy situation of the motors has been investigated; using firstly, the stator currents data patterns recognition, as a preliminary diagnosis. Secondly, the focus on the second harmonic of the supply frequency in the torque spectrum signal has shown its effectiveness as a complementary indicator of voltage unbalance. The steady-state of the induction motor and the several unbalanced voltage systems presented, were done by a simulation using the well-known Matlab