34f08f34_rials_patent_application_class__Description
20100243197 09-30-2010 [Description] 
PRESSURE CASTING OF ELECTRIC ROTORS - A rotor for an induction motor and a method of preparing same. The method includes making a squirrel-cage rotor made up of a cage and a laminate stack by forming a mold around the stack, heating the stack and introducing a molten metal into the mold such that the molten metal substantially fills a space defined in the stack that corresponds to the cage. In one form, the space includes slots or related channels formed in the stack that upon filling with the molten metal become longitudinal bars that form electric current loops with end rings of the cage. By heating the stack and maintaining it at a temperature high enough to keep the molten metal in a substantially molten state at least long enough for it to flow through the slots of the stack, premature freezing of the molten metal is avoided. In addition, by providing low pressure to the molten metal in conjunction with the elevated temperature in the stack, flow is promoted to ensure a substantially porosity-free, fully dense squirrel-cage for the rotor.
Utilizing particular mold materials patent application class