Faults Classification Scheme for Three Phase Induction Motor

Introduction

Induction machine is very common in industrial systems. Fault detection, diagnosis and classification of Induction machines have received considerable interest in the last decades. These motors are the most widely utilized electrical machines, mainly due to their advantages such as: stability properties, robustness, durability, power to weight ratio, low production costs and easiness of controlling them (Acosta et al., 2004).

Despite their numerous advantages, still many types of faults might occur, which can cause unexpected safety risks and economic expenses, delays in processes and overall production line breakdown. Faults occur most of the time in the rotor and the stator of an induction motor, while many of these faults reveal their existence gradually and thus sometimes it is very difficult to be identified in due time (Aydin et al., 2007).

Among the most common faults that can be found within the area of induction motors are: a) opening or shorting in one or more of a stator’s phase windings (Nandi & Toliyat, 2005; Seshadrinath et al., 2013), b) broken rotor bar or cracked rotor’s end-rings (Santos et al., 2006), c) static or dynamic air–gap irregularities (Acosta et al., 2004), and d) bearing failures (Bouchikhi & Benbouzid, 2013). More statistical results, obtained from reports by the Motor Reliability Working Group of the IEEE Industry Applications Society (IAS), which surveyed 1141 motors, and the Electrical Power Research Institute (EPRI), which surveyed 6312 motors, are summarized in Table 1. As one can observe, bearing-(mechanical) and winding (stator)-related failures are the dominant trouble areas (Mercangoz & Doyle, 2006). From another point of view motor, faults can be categorized into two types, depending on their origin, e.g. mechanical and electrical, or it can be classified according to their location, e.g. stator and rotor. Usually, other types of fault like bearing faults refer to rotor faults also because they belong to the moving parts (Nandi & Toliyat, 2005).