A New Approach to Multi-Segmented Rotor Slot Design for Induction Motors Part I

Appropriate segmenting and shaping of the rotor slot and bar cross-section, with respect to the skin-effect developing during acceleration, has a great potential in the design optimization of squirrelcage induction motors. - Inherent major non-linearities of the pertinent complex mathematical relations, though, tend to make this potential inaccessible and hidden. This three-part paper introduces a novel concept, as the foundation of a comprehensive model theory, designed to break through the "non-linearity" barrier. The derived analysis techniques proved to handle complex speed-torque curve shaping and motor performance optimization problems successfully and efficiently. The presented approach was also instrumental in producing a related invention (U.S. Patent, see Ref. 3), first applied to a group of several large 2-pole motors having special acceleration requirements. The main principle of the model theory is to establish an in-depth direct contact between the performance-effects of the rotor slot geometry and the mental design-optimization process. A great emphasis is given to the visualization of the coherences of electro-magnetic phenomena, motor geometry and motor performance.