It has been noted that, in the induction motor the mechanical load oscillations can produce stator current spectrum harmonics, similar to the ones of the broken bar fault. As a consequence, these two different conditions have to be reliably distinguished. This paper proposes a new method aiming to this direction. More specifically, it is proposed to monitor the inherent eccentricity harmonics and their sidebands in order to reliably distinguish whether there is a broken bar fault or not, in the presence of mechanical load oscillations. The proposed method has been tested experimentally for different load and saturation levels of a cage induction motor and the results prove to be satisfying for all studied conditions.