Abstract—With the increased use of permanent magnet synchronous motors (PMSMs), efficient online condition monitoring and accurate fault diagnosis for these machines are very important. In order to reduce downtime and avoid unsafe operating conditions, it is essential to establish a methodology capable to detect incipient turn faults. This paper analyzed the consequences of turn-to-turn circuit faults between two phases in a PM synchronous motor. Thus, a simple method based on rotor speed ripples is proposed for detecting stator winding faults. Also, a fault index allows quantifying the severity of the fault. This latter seems to be well adapted for PM motors health monitoring and interturn fault diagnosis. Experimental results are included to show the ability of the proposed strategy to detect incipient faults.