Detection of induction machines rotor faults at standstill using signals injection

The main topic of this paper is to examine the feasibility of detecting the rotor faults of induction machines by performing standstill tests. It has been shown that by feeding the machine with special excitation signals such as discrete interval binary sequence (DIBS) and multisine, it is possible to excite with low-frequency resolution the faulty modes by analyzing the stator current and the stray flux measured by an external flux sensor. This method can be used for quality control just after manufacturing the rotor and mounting it within the stator frame. The proposed technique is fully general and can be applied to a three-phase squirrel-cage induction machine at standstill. Experimental measurements are made both on healthy and faulty machines and the comparison gives a difference in the external flux and stator current signatures which are basically the most commonly used methods for rotor fault detection.