Experimental and numerical investigations on rotational fluxes in stator cores of three-phase motors

A test device constituted by a three-phase stator equipped with pick-up coils and by a barless rotor has been realized. The device, driven by a synchronous motor, has been employed for a thorough investigation of the magnetic behavior of the stator core during the no-load test. The analysis has been developed under sinusoidal, six-step, and 12-step voltage supplies. The measured quantities have been compared with the results provided by a two-dimensional finite-element model that includes vector hysteresis and eddy currents. Good agreement has been generally found, in particular on the prediction of the flux density loci.