Matlab command | plot_Ft_cfft2 |
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Module | EM.pp |

Description | PLOT_FT_CFFT2 plots the complex 2D Fourier transform of the airgap tangential magnetic force per unit area |

Parameters | |

Restrictions | |

See also | plot_Ft_fft2, plot_Ft_fft2_stem, plot_Fr_cfft2 |

### Result

This **MANATEE software post processing** plots the **2D complex Fourier Transform of tangential magnetic pressure** as a 3d stem plot in dB scale:

Negative wavenumbers and frequencies account for the different propagation direction of force waves. The largest force harmonics should occur at r=2p (twice the number of pole pairs), f=2fs (twice the fundamental electrical frequency), and at r=0 f=0 (static force). Note that **only the lowest force wavenumbers are important in magnetic noise and vibration process**, and that **both radial and tangential force harmonics** can create radial deflection of the yoke.

The reference level of the pressure dB scale can be tuned in

`Input.Plot.PM0ref`

For further plot options (e.g. change axis) see How to change plot options.

This type of graph is very useful to identify which are the main harmonic forces responsible for** magnetic noise and vibration of electrical machines**. When a large force harmonic is close from a natural frequency, large vibration and noise is expected.