This paper addresses the design of a multi-three phases sectorial permanent magnet synchronous machine for bearingless applications. After a brief description of the mathematical model of this machine topology along with some preliminary design considerations, an optimization routine is first described and then applied with the aim of minimizing both the machine total losses, wrench ripple and machine nonlinearities. Several wrench targets are considered as well as different constraints about the wrench error, leading to some design guidelines for a given outer envelope. The rationals behind the selection of the final design to manufacture are explained analysing the optimal designs performance.