Patent ID: 7893589
Filing Date: 2011-02-22
Classification: H02K

Abstract:
1. Apparatus comprising an AC-induction-motor rotor lamination having a central longitudinal axis and a plurality of circumferentially spaced apart rotor slots, wherein the rotor slots are open, wherein adjacent rotor slots define a rotor tooth, and wherein each rotor slot includes: first and second corners, a straight slot base extending from the first corner to the second corner and having a midpoint, wherein the slot base is perpendicular to a first radius from the central longitudinal axis to the midpoint of the slot base, a third corner, a straight first slot side extending substantially radially toward the central longitudinal axis from the second corner to the third corner, a fourth corner, wherein the third and fourth corners are disposed a same radial distance from the central longitudinal axis, a straight second slot side extending substantially radially toward the central longitudinal axis from the first corner to the fourth corner, a rotor-slot opening centered on the first radius, a first curved side extending a first curved length from the third corner to the rotor-slot opening, wherein the first curved side is convex, as seen from inside the rotor slot, from the third corner to proximate the rotor-slot opening, and wherein any radius from the central longitudinal axis to the first curved side will intersect only a single point on the first curved side, a second curved side extending a second curved length from the fourth corner to the rotor-slot opening, wherein the second curved side is convex, as seen from inside the rotor slot, from the fourth corner to proximate the rotor-slot opening, and wherein any radius from the central longitudinal axis to the second curved side will intersect only a single point on the second curved side, and wherein the rotor slots include circumferentially adjacent first and second rotor slots, wherein the first slot side of the first rotor slot is parallel to the second slot side of the second rotor slot.