Patent ID: 8511367

Claim:
A method for forming a rotor for an induction motor, comprising: assembling a rotor core comprising stacking a plurality of steel laminations and stacking first and second end elements at respective opposite ends of the stacked plurality of steel laminations, wherein each of the plurality of steel laminations includes a plurality of apertures and the first and second end elements each includes a plurality of tapered apertures corresponding to the plurality of apertures, wherein the stacking aligns the apertures and the tapered apertures to form a plurality of conductor bar grooves, wherein stacking first and second end elements at respective opposite ends of the stacked plurality of steel laminations comprises for each end element stacking a set of steel laminations wherein each steel lamination of the set of steel laminations includes a plurality of apertures and wherein each aperture of each subsequently stacked one of the set of steel laminations is larger than the previously stacked one of the set of steel laminations whereby the plurality of tapered apertures of the first and second end elements are formed; placing the rotor core into a casting mold; and introducing molten metal into a first end of the casting mold, the molten metal flowing from the first end of the casting mold through the plurality of conductor bar grooves to a second end of the casting mold, the molten metal solidifying to form conductor bars in the plurality of conductor bar grooves and solidifying to form shorting rings across exterior portions of the end elements within the first and second ends of the casting mold.