Condition Monitoring of Wound Rotor Resolvers

Resolver is an electromagnetic sensor for calculating position and speed in motion control drive of electrical machines. Due to electromechanical structure of the machine, occurrence of the mechanical faults includes static and dynamic eccentricities (SE, DE) is inevitable. Even an inherent level of SE exists in newly manufactured machines. Furthermore, due to thin wires of the stator and rotor windings short circuit fault has also high probability. Since the accuracy of the resolver is significantly affected by electrical and mechanical faults, it is required to diagnose them at the very beginning of their development. In this paper, some indices are proposed for condition monitoring of wound rotor resolvers under mechanical and electrical fault. It is shown that the proposed index of each fault is unique and is not excited by other fault. The discussions are done using time stepping finite element method and the results are verified by experimental tests on prototype resolver.