During the design of permanent magnet synchronous machines (PMSM), the first step that engineers have to do, concern the choice of the topology, i.e. the slot/pole combination. Given that the performances of the machines are strongly related to this combination, the choice has to be fully justified. Fractional slots (FS)-PMSM offers several advantages and have been focused by a lot of researches. However, depending on the topology, these machines could have major drawbacks as magnetic noises, high iron and eddy-current losses and low fault-tolerance. The aim of this paper is to give an overview of each machine considering the most common slot/pole combination in order to single out if a topology is suitable or not. A special focus is also done on the homopolar component which traduces the machine's fault tolerant capability required for embedded applications.