An investigation of the influence of bearing failures on the efficiency of an induction motor

The influence of the technical condition of bearings on the efficiency of induction motors (IMs) with a squirrel-cage rotor was considered. The experiments were carried out using induction-motor tests in the rated nominal regime with one operable bearing and two faulty ones, which had defects of the outer and inner parts. The bearing defects increase the energy loss, which leads to increased heat dissipation in the contact zone of its components, overheating, and reduction of motor efficiency. More accurate data on changing the efficiency of IMs with faulty bearings taking into account the heated state of the machine that is close to actual operating conditions were obtained. Thermal-imaging inspection of motor was performed, the graphic data characterizing the changes of temperatures of units and the machine efficiency when operating with a faulty bearing are presented. A diagnostic technique of the bearing condition by means of integral parameters of vibration acceleration that makes it possible to analyze the potential defects taking into account the weak level of their activation and the shift over the frequency response is considered.