Induction motor diagnosis using voltage spectrum of an auxiliary winding - time varying load torque

In this paper, a new method for induction motor fault diagnosis is presented. It is based on the so-called voltage spectrum of an auxiliary winding which is a small coil inserted between two of the stator phases. An expression of the inserted winding voltage and its Park components are presented. After that, discrete Fourier transform analyzer is required for converting the voltage signals from the time domain to the frequency domain. Simulations results curried out in the case of an oscillating, varying load torque and non defected motor show the effectiveness of the proposed method.