Design of a 75 kW - 167 rpm axial-flux permanent magnet synchronous motor for copper mining applications

The rise in energy costs in the last five years has compelled the copper mining industry to encourage researchers to develop more efficient drives. It is under this scope that the authors of this paper are proposing the design optimization and construction of a 75 kW - 167 rpm central-stator permanent-magnet axial-flux synchronous-motor in order to drive, without any velocity adjustment mechanism, the flotation cell paddles used to concentrate the copper minerals. The geometrical quantities were optimized for maximum efficiency and the design incorporates in the data the load angle (delta). A 120degC as average temperature in the stator windings and demagnetizing effect were considered. Also cogging-torque reduction techniques are proposed and evaluated with a finite element software. The paper contains the complete algorithm and the results match those observed in an 8 kW laboratory prototype