Inter-Turns Fault Diagnosis for Surface Permanent Magnet based Marine Propulsion Motors

Fault analysis of marine generators is paramount to improve reliability and accessibility of a marine electrical power system. Inter-turns fault is presumably the most common fault in a PMSM and the symptoms associated with this fault in many machines are undetectable, depending on the level of fault. This paper proposes a novel method to use search coils to determine the inter-turns fault in a Surface Mounted Permanent Magnet Machine (SPMM). This technique would reveal data to pinpoint which slot is affected by the fault and how fault symptoms can easily be segregated from other asymmetric problems such as load imbalance and input unbalanced voltage. The proposed model used for simulation in FEA using MAXWELL 15 is a 3-phase, 42 poles, 54 slots fractional slot concentrated wound (double layer), surface mount PMSM. In addition to the use of search coils, the proposed research also looks into the torque profile with various conditions of fault, analyzes the machine current using symmetrical components and discrete wavelet transform.