Skew slots modeling: 2D, 3D or 2½D

Modeling in 2 or 3 dimensions

The progressive improvement of the computation power and speed of computers has permitted the utilization, as an industrial tool, of the transient analysis of motors by the finite element method.

For most of the electrical machines, a bi-dimensional modeling (2D) is enough.

The three-dimensional modeling (3D) provides more precise results, but it remains very costly in terms of software resources.

Modeling in 2½ dimensions

The skew of the rotor or stator slots in the machines represents a problem for the bi-dimensional calculus because of the axial variations of the magnetic field due to the changing orientation of the rotor as to the stator.

For an analytical resolution method, the swinging can be taken into consideration by means of a factor called skew factor.

As to the numerical resolution methods, it is often modeled by means of a technique called ‘Multilayers'. Equally, we speak of modeling in 2½ dimensions.