Induction motor rotor and a method of manufacturing the same

An induction motor rotor assembly comprising:

• a rotor, comprising a first axial end, an opposite second axial end, and an outer peripheral surface that extends between the first axial end and the second axial end;
• a sleeve;
• and
• first and second electrical connection portions,
• the rotor further comprising a plurality of axial, re-entrant slots machined axially along the outer peripheral surface of the rotor such that the re-entrant slots open at the outer peripheral surface and extend radially inward from the outer peripheral surface, the sleeve extending circumferentially around the outer peripheral surface of the rotor, the sleeve being located radially outward of the outer peripheral surface of the rotor, the sleeve comprising a plurality of axial re-entrant slot bars extending radially inwardly from the sleeve, each re-entrant bar having a first end and an opposite second end, each axial re-entrant slot bar being accommodated in a respective one of the axial re-entrant slots, and each re-entrant slot bar being formed by material of the sleeve that has been filled into a respective one of the re-entrant slots,
• the first electrical connection portion being attached to the first axial end of the rotor and connecting together the first ends of each of the axial re-entrant slot bars,
• the second electrical connection portion being attached to the second axial end of the rotor and connecting together the second ends of each of the axial re-entrant slot bars.