Spectrogram - I, PSI, N

1. Positioning and objective

The aim of the test “Mechanics – NVH – Spectrogram – I-Ψ-N” is to perform NVH analysis on the machine when operating at a set of targeted working points defined with the following inputs values I,Ψ,N (Magnitude of current, Control angle, Speed).

“Working point – Sine wave – Motor – I, Ψ, N” illustration

This test give data allowing NVH prediction in early electromagnetic and design stage.

The modal analysis of the stator mechanical structure, the radiated sound power spectrogram per engine order versus speed and the resulting overall weighted radiated sound power versus speed are computed and displayed.

These results allow seeing 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 – I-Ψ-N”.

Family Mechanics
Package NVH
Convention #
Test Spectrogram - I - Ψ - N
Positioning of the test “Mechanics – NVH – Spectrogram – I-Ψ-N”

2. User inputs

A list of working points must be defined in a file. They are described with the four following input parameters:

  • The supplied line current, or current density (rms value),
  • The control angle
  • The speed

In addition, winding temperatures must be set.

3. Main outputs

Test results are illustrated with data, graph and tables.

  1. Curves to give an overview of the electromagnetic behavior of the machine versus speed

    • Power
    • Mechanical torque
    • Line current
    • Control angle
  2. Graphs, curves, and maps to illustrate NVH analysis results

    • Modal analysis
    • Radiation efficiency
    • Radiated sound power spectrogram in speed-engine order area
    • Radiated sound power spectrogram in speed-frequency area
    • Overall weighted radiated sound power versus speed