Magnetic Force Signature Analysis


This key feature of Manatee e-NVH software gives the frequency signature of main magnetic force harmonics (excitation frequencies and wavenumbers) depending on slot/pole/phase combinations, electrical machine topology (e.g. induction or synchronous machine, inner or outer rotor), load state (e.g. no load, full load) and supply (e.g. sine / PWM). Calculation of magnetic forc harmonics is based on analytic models and therefore gives instantaneous results, making it easy to do what-if scenario.

Results are presented as a Campbell diagram of magnetic lumped force harmonics function of speed and frequency. The physical origin of a given magnetic Load Case in terms of permeance, magnetomotive force, flux waves combinations as well as in terms of excitation sources (rotor/stator excitation fields, slotting harmonics, armature winding or magnet space harmonics).

Note: MFSA can be deployed as a standalone software and can be directly ordered online. A tutorial on MFSA can be downloaded here.


Magnetic Force Signature Analysis (MFSA) tool can be used by electrical engineers in the early design phase for a quick qualitative comparison of Maxwell excitations among different topologies. Once a noise issue has been identified, electromagnetic design engineers can also use this feature to discriminate the harmonic origin of the electromagnetic excitation (e.g. combination of 11p and 13p rotor mmf harmonics with first order slotting harmonic) in order to implement electromagnetic design optimization.

It can also be used by mechanical and acoustic engineers to have a first estimate of the main resonances between magnetic force harmonics and main lamination modes.

Finally, it can be useful for NVH test engineers in order to identify the nature of electromagnetic excitations from experimental spectrograms, and easily discriminate magnetic noise from other noise sources (e.g. mechanical & aerodynamic noise).