Integrated Experimental Analysis of Vibration Response, Thermal Characteristics, and Energy Efficiency Degradation under Combined Shaft Misalignment in a Motor–Generator System

Abstract

One of the major reasons for the failure of rotating machinery is the failure of mechanical components due to shaft misalignment and it affects the vibration, thermal characteristics and energy efficiency. In practice, combined shaft misalignment is more common than isolated failures, but the overall impact of combined misalignment has not been studied sufficiently. This study experimentally investigates the effects of combined shaft misalignment on the vibration response, thermal behaviour, and energy efficiency of a motor-generator system. Experiments were carried out using a 1.1 kW three-phase induction motor coupled to an electric generator under aligned and combined misalignment conditions at load levels of 350 W, 600 W and 1000 W. Shaft alignment was performed using the face and edge methods. The vibration severity was evaluated in terms of RMS velocity according to ISO 10816. The surface temperature was measured by infrared thermography. System efficiency was evaluated based on the electrical input and output power. The results show that the combined shaft misalignment always produces higher vibration levels and surface temperature, lowering the system efficiency. The results highlight the need for integrated multi-parameter condition monitoring for enhanced reliability and performance assessment of rotating machinery.