Faulted motor signal acquired at actual working spot usually includes large amount of noise. In traditional method analyzing is performed on the denoised signal, but some useful signals are losed in processing. A new method based on stochastic resonance theory is presented to detect the fault of the rotor bar breaking. When the system parameters are appropriately selected, the noise can be suppressed and the faulted signal can be detected. Fault detection instances in laboratory demonstrate that the present...