Fault analysis of non-uniform airgap length in frictionless linear induction motor drive

Application of linear induction machines (LIM) for electric propulsion have been investigated intensively in the past few decades. The advantages of LIM as applied in the propulsion system include easy maintenance, high acceleration/deceleration, and low cost to name a few. One of the active areas of research is aimed at combining the LIM with magnetically levitated system (Maglev) to achieve frictionless transportation system. Maintaining a uniform airgap is a prime goal in development of such system. Therefore timely detection of non-uniform airgap is an important task in this family of transportation systems. Using an experimental LIM and with the help of finite element analysis (FEA), effect of non-uniform airgap length on the force and magnetic characteristics of LIM has been explored. Furthermore, the detection method for this type of fault has been developed to monitor airgap length of LIM for high speed frictionless propulsive applications.