Electric induction machine

An electric induction machine, comprising:

• a housing having an inner space;
• a stator assembly arranged annularly within the inner space of the housing;
• a shaft rotatably supported so as to concentrically extend through the stator assembly;
• and
• a rotor assembly fixed to and surrounding the shaft within the inner space, the rotor assembly being disposed concentrically with and inside the stator assembly, wherein the rotor assembly further comprises:
• a cylindrical rotor frame;
• a plurality of axially extending longitudinal rotor grooves spaced circumferentially along the rotor frame, each rotor groove being rectangular in shape;
• a plurality of longitudinal rotor bars accommodated within the rotor grooves, each rotor bar comprising a rectangular shape corresponding to the rectangular shape of a corresponding rotor groove except for a chamfer region;
• a plurality of slits, each slit extending radially outward from a radial outer side of each respective rotor groove to an outer circumference of the rotor frame;
• and
• the chamfer region formed in only each respective rotor bar as a gap between each respective rotor groove and rotor bar pair at a position corresponding to a radially outer internal corner region of the rotor groove,
• wherein the gap of the chamfer region does not extend in the tangential direction of the rotor frame beyond a tangentially closest side of the slit.