Novel Line-Start Rib-Less PM-Assisted Synchronous Reluctance Motor for Submersible Bore-Well Pump

The presence of radial and tangential ribs adversely affects the electromagnetic performance of a Synchronous Re-luctance Motor. However, they are necessary from the viewpoint of the structural stability of the motor. This paper proposes a novel line-start rib-less permanent magnet-assisted synchronous reluctance motor that improves electromagnetic performance by eliminating ribs/bridges/posts in the rotor structure. In the absence of ribs, the structural integrity of the rotor structure is maintained by the cage winding bars and end rings. The cage winding bars and end rings, which are used to facilitate the self-starting of the motor, are slightly modified to serve the additional role. The efficacy of the cage bars in imparting structural integrity is verified using structural simulations. The resulting rib-less motor has superior performance characteristics in terms of efficiency, power factor, and torque density compared to similar-sized motors that have radial and/or tangential ribs. These claims are substantiated through electromagnetic time-stepping 2D Finite Element Analysis, and the simulation results so obtained are presented.