Abstarct: Abstract Axial flux permanent magnet synchronous machines have constantly attracted researchers due to their capabilities and advantages, including high power density and efficiency, as well as advances in related topics. The design of electric machines is designed with reliable design algorithms. In this thesis, the detailed and optimal design algorithm of the double-sided slotted axial flux surface permanent magnet synchronous motor is explained in full detail. In this design algorithm, it has been tried that without the need of trial and error and checking the data and choices obtained from the proposed algorithm, they are sure that the obtained data are correct and accurate. In the following, to validate this claim, a motor with the proposed design algorithm is simulated with the finite element method software and the simulation results are compared with the data of the proposed algorithm. Gearboxes, as mechanical devices, help in transferring rotational movement and power from one part to another part of the system. Gearboxes are usually used to reduce or increase torque, change rotational speed, change direction, and convert rotational to linear motion and vice versa. To determine the speed range for using gearboxes, machines are designed using the proposed algorithm for the number of poles and different frequencies to be compared and checked with gear motors at the same speeds. The results of this research are presented completely. The results show that gearmotors perform better in terms of efficiency and mass for speeds lower than 250 rpm.