Cast rotor and method

A method for forming a rotor assembly including a cast rotor frame includes positioning a preheated rotor core defining a plurality of passages in a mold cavity such that the mold cavity and the rotor core define the rotor frame including a plurality of conductor bars defined by the plurality of passages in fluid communication with first and second end portions of the mold cavity. Molten metal is quiescently introduced into the mold cavity through an ingate and simultaneously flowed through the plurality of passages prior to filling at least one of the first and second end portions of the mold cavity to form the cast rotor frame. Entrained air and impurities may be displaced from the passages by the flow of molten metal and vented or entrapped by a biscuit. The rotor frame and conductor bars thus formed may be characterized by high conductivity, negligible porosity, and minimal oxides.