Consequences of Propeller Failure on Multiphase Synchronous Motors in Clean Aircraft Propulsion

In the paper reference is made to multi-phase permanent magnet motors driving aircraft propellers. Variations in the performance of these motors are investigated when a propeller failure occurs, consisting of asymmetrical mass loss of the blades. Considered motors have surface-mounted magnets on the rotor and armature windings of the tooth concentrated type. The analyzed propeller failure is dynamically simulated using the Jeffcot's model. Some cases-study are examined with reference to different values of the rotation speed and of the mass loss of the blades, which influence the maximum displacement of the rotor with respect to its ideal position, which corresponds to a symmetric air-gap configuration. The resulting air-gap distribution of the magnetic flux-density and the motor torque are evaluated in the different examined cases using a FEM analysis approach. The results obtained are compared to those under healthy conditions, also highlighting the specificities of the multiphase structure of the stator.