A cage rotor of an asynchronous machine includes a magnetically conductive body having substantially axially running slots with conductors connected to end faces of the magnetically conductive body in an electrically conductive manner by short circuit rings. The short circuit rings have an outer side, an inner side, a front side, and a rear side. A supporting element made of a high-strength material is located at least radially within the short circuit rings, i.e. on the inner face, with the supporting element being connected to the short-circuit ring, at least in one section, with a material fit.

In induction motors, efficiency is improved and a maximum torque is increased. For a magnetic flux density of the stator pole for each phase of an induction motor, a circumferential magnetic flux density distribution is controlled to any distribution state, from a trapezoidal wave-like distribution close to a square wave to a sinusoidal distribution. In particular, motor efficiency in a range of low to medium rotations is improved. The motor structure is designed to reduce the leakage inductance of the rotor windings, and the motor and control thereof are optimized for each other. This increases the maximum torque of the motor more effectively. In addition, the high efficiency of the motor makes it possible to reduce the size of the drive circuit.

A rotor for a rotary electric machine, including: a stack of magnetic laminations each having openings, the superposition of these openings within the stack forming slots, at least some of the openings having, on at least part of their periphery, friction reliefs, electrically conducting bars made of a first material, received in at least part of the slots and coming to bear via at least one principal face against said reliefs.

Methods and systems for cooling an electric motor are provided. An electric motor cooling system, in one example, includes a stator at least partially surrounding a rotor and an inner passage extending axially through the rotor and including an inlet and an outlet. The cooling system further includes an outer passage including an inlet in fluidic communication with the outlet of the inner passage and an outlet in fluidic communication with an inlet of the inner passage and a phase change material in the inner passage and the outer passage.

A method for producing a squirrel-cage rotor of an asynchronous machine includes the following steps: providing a main body, which is magnetically conductive at least in parts and has substantially axially extending grooves; inserting electrical conductors into the grooves in such a way that the conductors protrude from the axial ends of the magnetically conductive main body; positioning electrically conductive end rings, which have a plurality of openings for receiving the respective conductors; and establishing electrical contact between the conductors and the end rings by way of one or more additive manufacturing processes.

A rotor of an induction machine includes a rotor core structure and a cage winding. The cage winding includes rotor bars in slots of the rotor core structure and end-rings connected to ends of the rotor bars. The ends of the rotor bars are attached to openings of the end-rings by expansion of the ends of the rotor bars in transverse directions of the rotor bars caused by axial press having been directed to the ends of the rotor bars. The material of the rotor bars is softer than the material of the end-rings. Thus, unwanted shape deformation of the end-rings can be avoided when the ends of the rotor bars are axially pressed. The material of the end-rings can be for example copper alloy with additions of chrome and zirconium, whereas the material of the rotor bars can be for example copper.

A refrigeration cycle apparatus (1) is capable of performing a refrigeration cycle using a small-GWP refrigerant. The refrigeration cycle apparatus (1) includes a refrigerant circuit (10) and a refrigerant enclosed in the refrigerant circuit (10). The refrigerant circuit includes a compressor (21), a condenser (23), a decompressing section (24), and an evaporator (31). The refrigerant contains at least 1,2-difluoroethylene.

A squirrel-cage induction rotating electrical machine comprises: a solid rotor, a stator, and bearings. The solid rotor includes a shaft part, a columnar-shaped rotor core part integrally formed with the shaft part and having rotor slots formed therein, and a plurality of conductor bars passing through the respective rotor slots and coupled together at both axial ends outside the rotor core part. The stator includes a cylindrical stator core provided radially outside the rotor core part, and stator windings passing through a plurality of respective stator slots which are formed in the radially inner surface of the stator core. An outer wall and an inner wall of each rotor slot are tilted at a predetermined angle or more with respect to a plane including a rotation axis of the shaft part.

A rotor for an induction motor includes a rotor core having a hollow portion on a central portion wherein a shaft is coupled to the rotor core by being inserted through the hollow portion, a plurality of slots radially formed in the rotor core around a central axis of the shaft, a plurality of conductor bars coupled to the plurality of slots, and an end ring electrically connecting the plurality of conductor bars to each other, wherein the rotor core is thermally treated above Curie temperature to form a predetermined pattern on an outer circumference of the rotor core.

In a method for producing a squirrel-cage rotor of an asynchronous machine, conductor bars of a first conductive material are inserted into slots of a magnetically conductive body such as to project out of at least one end side to form a projection. A short-circuiting disc of a second conductive material is positioned under pressure on the projection with a clearance fit of approximately 0.1 mm relative to a radially outwardly open recess of the short-circuiting disc. The short-circuiting disc is heated while the conductor bars virtually contact the short-circuiting disc. At least the projection of the conductor bars is coated with a third material at a layer thickness to form an alloy with the first and second materials after heating so that the third material is fully dispersed in the first and second materials as a result of the third material being diffused into the first and second materials.