Effect of Air gap variation on characteristics of an Axial flux hysteresis motor

Axial flux hysteresis motor (AFHM) such as other types of hysteresis motor is self-starting synchronous motor that use the hysteresis characteristics of magnetic materials. It is known that the magnetic characteristics of hysteresis motor could be easily affected by air gap and structure dimensions variation. Air gap length plays an important role in flux distribution in hysteresis ring that can influence the output torque, terminal current and efficiency of AFHM. Regarding this issue, in this study effect of air gap variation on performance characteristics of an axial flux hysteresis motor is investigated. Effect of air-gap length on electrical circuit model is perused. Finally, simulation of AFHM in order to extract the output values of motor and sensitivity analysis on air gap variation is done using 3D-Finite Element Model. The simulation is based on Maxwell's field equations for an axial flux type machine at synchronous speed. Also, a hysteresis loop in the shape of an inclined ellipse is adopted. This study can help designers in design approach of such motors.