Comparative Study between Two Diagnostic Techniques Dedicated to the Mechanical Fault Detection in Induction Motors

Among the main causes which have a great influence on the service life of rotating electrical machines are mechanical faults. The squirrel cage induction motors are one of the most important induction motors in industrial and modern industrial applications. The reasons are the low cost, robustness, and low maintenance. In general fault causes unwanted vibrations in rotating machines and the rolling element bearing faults affect the induction machines with a significant percentage. It is a major problem among different faults because it can cause catastrophic damage. Early and accurate detection of rolling element bearing faults are essential for both effective fault management and fault isolation. This paper presents a detailed study of rolling element bearing faults in squirrel cage induction motors using two recent diagnostic techniques. The first technique uses the stator current signal based on the fast Fourier transform. According to this technique, it is carefully checked the spectral content of the stator current. The second technique uses the stray flux signature analysis. Experimental tests for different conditions as low load, full load operation, healthy and faulty states of the induction motors have been performed. So, a detailed comparison between the two techniques led us to achieve a judicious decision about the rolling element bearing faults detection.