Experimental and Analytical Study of Single-Phase Squirrel-Cage Induction Motor Considering End-Ring Porosity Rate

Single-phase squirrel-cage induction motors are widely used in household and industrial electronics, because of their simplicity, low cost, and ruggedness. The cage rotor of the induction motor is produced using laminated electrical steel sheets subjected to die-casting processes with various manufacturing parameters. However, the die-casting process generates pores in the cage-rotor end-ring. These pores have a significant effect on the motor properties, which cannot be accurately analyzed. In this paper, squirrel-cage rotors with different porosities were prepared by varying the die-casting process. Then, the end-ring porosity was accurately analyzed using X-ray computed tomography. The inter-bar resistance of the squirrel-cage rotor was calculated from the end-ring porosity rate. Finite-element analysis (FEA) was used to predict the effects of porosity on the motor performance. Finally, the motor was tested, and the measurements were compared with the FEA-predicted results. The analytical and experimental results obtained for a 1.5 kW single-phase squirrel-cage induction motor were very similar, when the end-ring porosity was included in the analysis.