Patent ID: 8403026

Claim:
A method of making a squirrel-cage rotor for an electric motor, said method comprising: forming a sand-based mold around a laminate stack portion of said electric motor; inductively heating said laminate stack with an inductive heating rod with an inductor holder, the inductive heating rod being inserted into a central void formed in plates of the laminate stack, the inductive heating rod being segmented into a plurality of separately controllable sections providing varying amounts of heat along the axial dimension of the laminate stack and operated to remain on during a filling of the mold with molten metal; introducing a molten metal into said mold using low feed pressure of between about 10 pounds per square inch gauge and about 30 pound per square inch gauge such that said molten metal substantially fills a space defined in said laminate stack that corresponds to a cage of said rotor, said heated laminate stack possessing sufficient thermal mass to keep said molten metal in a substantially molten state until a substantial entirety of said cage is formed; cooling said molten metal and said laminate stack such that said rotor is substantially solidified; and removing said substantially solidified rotor from said mold.