How to simulate an uneven airgap?

The non-circularity of stator and rotor laminations can be due to segmentation effects, welding effects, manufacturing tolerances, deflections due to weight and thermal expansion forces, etc. The non-circularity of the laminations modulate the magnetic forces and therefore significantly change the vibration and acoustic behaviour of the machine. These effects can be studied in MANATEE using the permeance / mmf model.

To study the effect of a periodic change of the lamination shape (“flower-shape”), you have to set the following Input :

Input.Geometry.Nsegs = 6;
Input.Geometry.deflection_rates=0.2;
Input.Simu.type_stator_shape = 1;

This indicates that a 6 segment or 6 weldings stator is considered with +/- 20% deflection from the nominal airgap. The last parameter ensure that the stator periodic deflections due to segmentations and weldings are taken into account in the model.

The shape of the airgap can be checked with the command plot_airgap_shape :

Airgap shape
Airgap shape
plot_airgap_shape

A display amplification factor is used to plot the non-circularities in the structure Plot, you can change it by directly specifying

Input.Plot.disp_ampfactor=100
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