Load influence on induction machine torque and stator current in case of shaft misalignment

The aim of this study is to analyze both stator current and output torque spectra of a three-phase squirrel-cage induction machine in a hoisting winch system. These experiments are performed to show the influence of the shaft misalignment at different load and speed levels in motoring and braking modes. In this paper, it is observed that the influence of the shaft misalignment in the stator current and torque harmonics can be damped by increasing the load level for both motoring and braking modes.

I. Introduction

Three-phase induction machines are often critical components of many industrial processes and they are called the workhorses due to their widespread usage in industry. These electrical machines are basically associated to complex electromechanical systems in which they are the key point. Extensive works have been carried out to monitor electrical machines from both electrical and mechanical points of view and many advanced techniques have been proposed in the literature [1]. In this way, some characteristics can be affected by the different faults and the load level has to be considered as a key parameter for any related investigation.