Abstarct: For the motors operating just at synchronous speed, the use of variable frequency drives may totally weaken the steady state characteristics. Consequently, the cage is sometimes utilized as an alternative so that to directly drive the permanent magnet synchronous motors in the line start driving mode. In this thesis, a new cage structure is introduced for Axial Flux Permananet Magnet (AFPM) motors, for which the appropriate design algorithm is presented as well. baxsed on the simulation results of Finite Elements Method, the proposed cage structure is capable to drive the AFPM motor with the line start operation, in a proper manner. Moreover, this structure can be regarded as an efficient damper so that to damp the oscilations produced by disturbances and consequently to enhance the final synchronism speed. In a PM synchronous machine, the magnets play significant roles in the machine performance, and hence, their magnetization should be preserved as a very important issue that necessitates an appropriate attention. In response to the probable disturbances, the armature current may be severely increased. The armature reaction thus weakens the air-gap flux density produced by PM that may lead to the demagnetization of PMs. The simulation results of FEM demonstrate that in addition to the line start operation, the cage can also compensate the demagnetization of magnets due to the armature reaction effect. In order to improve the performance of the proposed cage structure, the demagnetization phenomena is completely investigated in the machine under study by using a novel approach. Thereby, an optimal cage structure is determined ultimately so that to the demagnetization effect can be compensated as much as possible and the motor can be properly operated in the line start mode, as well.