Gearbox monitoring using induction machine stator current analysis

The aim of this paper is the monitoring of a gearbox by using the stator current signature analysis in the driving induction machines. The detection of mechanical faults using the vibration signal analysis has been well studied before. Recently, some works have been performed in order to observe the vibration components of the mechanical part in the stator current spectrum for an induction machine but without any theoretical detail. This paper proposes a theoretical framework based on torque oscillations due to the characteristic torsional vibrations in a gearbox and the source of mesh and rotating frequency components in the stator current is presented. In order to verify the theoretical development, a test-bed based on a 5.5kW three-phase squirrel-cage machine connected to a gearbox has been used.