Rotor fault detection of induction motors by sensorless irregularity revolution analysis

A new method to separate broken rotor failures and low frequency load oscillations in three-phase induction motor

“…Phase current's analytic signal modulus obtained by Hilbert transform has been used in [3] for MSCA to detect broken rotor bar fault at very low slip. Phase modulation techniques based on analytical and space transformation signals is used for rotor fault diagnosis [4]. In [5], to improve fault diagnosis accuracy of broken rotor bar a method based on adaptive notch filter and Hilbert-Huang Transform is presented.…”

“…Analytic signal ( ) x t can be defined from actual signal x(t) and the Hilbert transform of this signal HT(x(t)), as in (4).…”

Rotor Cage Fault Detection in Induction Motors by Motor Current Demodulation Analysis

“…Over the 85% of full load the decrease is slightly greater. The values of Ira at a factory balanced rotor are still sufficient for a sensorless rotor electromagnetic field speed and speed irregularities measurement (Jaksch & Zalud, 2010). PM for rotor eccentricity slightly decreases with increasing load unlike PM for broken bars.…”

“…Previous investigations and experiments (Jaksch & Zalud, 2010) proved also an increasing oscillation of rotor magnetic field at fsp with increasing load which means the increase of Ispp. It means consequently the increase of aAPL, aAPH according to (3) at the same rotor fault size (dash line in Fig.3).…”