Abstract:

Induction motors are widely used electrical machines in converting electrical energy into mechanical energy. Common faults ıf induction motors are divided into two groups as electrical and mechanical faults. Electrical faults consist of stator faults and rotor faults. Mechanical faults include bearing failures, axial misalignment and other faults related to the mechanical components of the motor. Bearing failures has significant share in mechanical faults. One of the main causes of bearing failures is  the  misalignment between the motor and the load. In this paper, the effects of the misalignment problems between an induction motor and a load are investigated. A star-flexible coupling was used between the induction motor and the load. The motor was loaded with a self-excited synchronous generator. Motor-load (synchronous generator) misalignments were gradually adjusted by a laser coupling alignment tool. At each alignment level the stator current and vibration signals were recorded. Current and vibration signals were analyzed in the frequency domain. Then entropies of current and vibration signals were calculated. The change in the entropy of current and vibration signals due to misalignment were investigated experimentally. It has been shown that the misalignment problems can be analyzed with the change in entropy of stator current and vibration signals.

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