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”), a new project is set-up in tuto_test_SCIM_18 by copy/paste tuto_test_SCIM_01 with the following changes:
Input.Simu.type_stator_shape = 1;
Input.Simu.Nsegs = 6;
Input.Simu.deflection_rates=0.2;In the GUI, these parameters are available simulation GUI in the Fault group.
This indicates that a 6 segment or 6 weldings stator is considered with +/- 20% deflection from the nominal airgap.
Result interpretations
The model is run as usually using in the Matlab command line
>> run_MANATEE('tuto_test_SCIM_18');The shape of the airgap can be checked with the command plot_airgap_shape
- Stator 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
The influence on the variable speed sound power level can be checked using the sonogram (plot_VS_ASPL_spectrogram):
- Sonogram with uneven airgap
One can see that the acoustic noise spectrum is much richer than in the case of the ideal machine of tuto_test_SCIM_01:
- Variable speed noise spectrum
