Spectrogram  U, f, N
1. Positioning and objective
The aim of the test “Mechanics – NVH – Spectrogram – UfN” is to perform NVH analysis on the machine when operating at a set of targeted working points defined with the following inputs values U, f, N (LineLine voltage, Power supply frequency, Speed).
This test is available only in the beta mode. It means that all the computation process and results are not entirely qualified yet. However, this gives users, the capability to use and to evaluate this new feature by themselves.

“Working point – Sine wave – Motor – U, f, N” Illustration 
This test give data allowing NVH prediction in early electromagnetic and design stage.
The modal analysis of the stator mechanical structure, the sound power level spectrogram per engine order versus speed and the resulting overall weighted sound power level versus speed are computed and displayed.
These results allow to see if there are any problems linked with NVH over the considered speed range.
And finally, this test helps to answer the following question:
Could the machine have any risks in connection with NVH? Yes / No.
The following table helps to classify the test “Mechanics – NVH – Spectrogram – UfN”.
Family  Mechanics 
Package  NVH 
Convention  # 
Test  Spectrogram  U  f  N 
Positioning of the test “Mechanics – NVH – Spectrogram – UfN” 
2. User inputs
The three main user input parameters are the supplied LineLine voltage, the power supply frequency, and the speed (or the slip). In addition, temperatures of winding and squirrel cage must be set.
3. Main outputs
Test results are illustrated with data, graphs, and tables.

Curves to give an overview of the electromagnetic behavior of the machine versus speed
 Power
 Mechanical torque
 Line current
 Control angle
 Magnet temperature

Graphs, curves, and maps to illustrate NVH analysis results
 Modal analysis
 Radiation efficiency
 Sound power level spectrogram in speedengine order area
 Sound power level spectrogram in speedfrequency area
 Overall weighted sound power level versus speed