Abstract: A method of producing a squirrel-cage rotor for an induction motor, which includes a plurality of secondary conductors arranged respectively in through holes (16) of a laminated core (14), and a pair of end rings connecting the secondary conductors with one another at both axial ends of the laminated core (14). Each of a pair of reinforcing members (22) includes a cylindrical wall (26), an annular multi-aperture wall (28) provided with apertures (32) and extending in a radial inward direction from one edge of the cylindrical wall (26), and an annular end wall (30) extending generally parallel to the multi-aperture wall (28) in a radial inward direction from another edge of the cylindrical wall (26). Each reinforcing member (22) is arranged in a manner in which the multi-aperture wall (28) is brought into contact with one of the axial end faces of the laminated core (14) while the apertures (32) communicate with the through holes (16).

Abstract: A method and apparatus for making a rotor assembly for an electric motor wherein the rotor core of the assembly includes a stack of annular laminations having fixed molded annular end rings on opposed faces thereof with a rotor shaft extending through the core and fixed thereto by a molded rotor hub shaped in cup-like fashion at one end thereof to cooperate in forming an oil return member therewith.

Abstract: A die casting apparatus for forming rotors for electric motors. The apparatus includes a frame having at least two opposed stationary pressure plates and a rotating turret rotatively mounted betewen these stationary plates. The turret includes three apertures at three equally spaced locations around the turret. Tooling is arranged at each of the respective locations for forming a rotor. Compensating and casting tooling is located at a first station, pin pressing and trimming tooling is located at the second station and unloading and loading tooling is located at the third station. The operations at the respective stations proceed simultaneously. The operations are selected so that the combined operations of each of the stations will take approximately equal amounts of time.

Abstract: A method and apparatus for making a rotor assembly for an electric motor wherein the motor core of the assembly includes a stack of annular laminations having fixed molded annular end rings on opposed faces thereof with a rotor shaft extending through the core and fixed thereto by a molded rotor hub shaped in cup-like fashion at one end thereof to cooperate in forming an oil return member therewith.

Abstract: A die cast rotor for an electric motor in which an integral tubular oil return/rotor shaft mounting member is sealingly cast-in-place within the body of the rotor. The integral oil return/rotor shaft mounting member is preferably a one-piece impact extruded member. A method of fabricating such a die cast rotor is also disclosed.

Abstract: A rotor comprising stacked laminations having conductor slots and axial passageways provided with closed-slot spacer assemblies that are stacked in groups between selected axially spaced rotor laminations to hold said laminations apart while sealing the conductor slots thereby to form radial cooling ducts through the laminations of the selected axially spaced groups and around the closed-slot spacer assemblies. According to the method of the invention, the spacer assemblies are secured in selected operating position by being staked to certain of the main rotor laminations, and a characteristic staking procedure is used to secure individual plates of each of the assemblies together.

Abstract: Fractional horsepower induction motors having a fixed number of poles (and, accordingly, a single no load synchronous speed) that are particularly adapted for multi-speed operation when driving a fan load by changing the field strength of the main winding. Induction motors of N fundamental poles have squirrel cage rotor having a plurality of interrelated conductor bars and end rings that are arranged so that multiple sets of the rotor bars establish a predetermined number of separately identifiable cage sets such that the fundamental pole structure of the stator field is coupled with the rotor and such that the third harmonic of the stator field is not coupled with the rotor. The rotor slot number and total number of separately identifiable cage sets are selected so that a cage set pattern is provided that has two-thirds of a fundamental pole pitch.

Abstract: Die casting apparatus for casting parts such as rotors or the like comprises a three tie bar horizontally disposed die casting machine, with an indexing mechanism mounted on one of the tie bars for rotating the parts through six separate radially spaced work stations. The work stations include loading, casting, cooling, skew pin ejection, and unloading stations. The casting station includes a four plate die assembly comprising a runner plate, cover die, carrier plate, and ejector die. The die assembly employs pin-point gating and is formed such that the cast part is removed from the die and the runner system, and the runner system is ejected from the apparatus, while the part is at the casting station. A movable runner ejector plate having ejector pins ejects the runner from the runner plate. A compensating cylinder is provided for adjustment for variance in stack height.