Load influence on torque and stator current for induction machines running a planetary gearbox

The aim of this paper is to analyze both stator current and output torque spectra of a three-phase squirrel-cage induction machine in a hoisting winch system in order to show how they are influenced by a planetary gearbox behavior with different loads and speeds in both motoring and braking modes. In this paper, the effect of the planetary gearbox behavior is observed in the stator current and output torque by using the spectral signature which is produced by the torsional vibrations induced by the mechanics in healthy and faulty operations. It has been observed that the frequency components of the planetary gearbox in the stator current and torque frequencies can be damped by increasing the load level for both motoring and braking modes.