Radial force as a function of space (plot_Fr_space)

Post-processing documentation
Matlab commandplot_Fr_space
Module EM.pp
Description PLOT_FR_SPACE plots the airgap radial magnetic force per unit area as a function of space
Parameters
Restrictions
See also plot_Ft_space, plot_Fr_time, plot_Fr_fft2

Result

The calculation of Maxwell tensor is an important output of MANATEE software electromagnetic model as it generates magnetic forces responsible for electromagnetically-excited audible noise.

This particular post processing plots the radial force per unit area experienced by the outer structure as a function of airgap angle, including the corresponding Fourier analysis:

Airgap radial force as function of space
Airgap radial force as function of space
plot_Fr_space

One can see that it is negative because globally the outer stator tends to be pulled towards the inner rotor.

The largest harmonic (wavenumber) should correspond to r=2p (twice the number of pole pairs) and its magnitude should equal the DC component one (r=0). Note that only the lowest force wavenumbers are important in magnetic noise and vibration process.

Note that this 1D FFT graph gives only a partial view of the harmonics, as both space and time frequencies are involved in noise and vibration generation. A 2D Fourier transform of the radial force is available with plot_Fr_fft2.

To change the default plot options (e.g. time stamp of the plot, axis) you can read How to change post processing plot options ? article.

This graph helps identifying the space harmonics involved in radial magnetic pressure involved noise and vibration behaviour of the electrical machine.

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