Influence of Asymmetrical Stator Axes on the Electromagnetic Field and Driving Characteristics of Canned Induction Motor

Canned induction motors (CIMs) are particularly important for high vacuum application due to its low cost, simple design, and mechanically robust. Herein, this study reveals a mechanism of asymmetrical stator axes (ASAs) for CIMs and proposes six coefficients to describe ASA for CIMs under asymmetrical stator phase's windings. Using winding theorem, this study derived the electromagnetic field and driving characteristics in the healthy condition and ASA conditions for a 1.9 kW CIM, and analysed further using mathematical formulas and finite-element models. Both simulation and experimental results show good agreement, and significant variation was found in total harmonic distortion, the amplitude of air-gap flux density, and driving characteristics of CIMs. Further, investigation of back-electromotive force and stator current showed their efficacy as a diagnosis signature to detect the fault of ASA in CIMs. The obtained conclusions can serve as a valuable reference to design a high-performing CIMs control system.