US 11,888,366 B2
Electric induction machine
Mikael Heikel, Helsinki (FI); Mark Szucs-Bartfai, Helsinki (FI); Aron Szucs, Helsinki (FI); Blanka Szucs-Bartfai, Helsinki (FI); Zsolt Kovacs, Helsinki (FI); and Jan Westerlund, Helsinki (FI)
Assigned to ABB Schweiz AG, Baden (CH)
Filed by ABB Schweiz AG, Baden (CH)
Filed on Dec. 28, 2020, as Appl. No. 17/134,712.
Application 17/134,712 is a continuation of application No. PCT/EP2019/067314, filed on Jun. 28, 2019.
Claims priority of application No. 18180967 (EP), filed on Jun. 29, 2018.
Prior Publication US 2021/0119521 A1, Apr. 22, 2021
Int. Cl. H02K 17/20 (2006.01); H02K 17/42 (2006.01)
CPC H02K 17/20 (2013.01) [H02K 17/42 (2013.01); H02K 2213/03 (2013.01)] 19 Claims
OG exemplary drawing
 
1. 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.