Multi-simulation : Rotor slot number effect

In this new MANATEE software simulation project, the influence of the rotor slot number of the maximum vibration level due to Maxwell forces is studied at no-load.

This is done by copy/paste tuto_test_SCIM_05.m in a new project tuto_test_SCIM_29.m (or by loading it in the GUI).

The sensitivity analysis is activated:

Input.Simu.type_sensitivity = 1;

The design variable Zr (number of rotor slots) is chosen:

Input.Simu.names_var={'Zr;};

As it is a discrete variable with values inside a set, one puts

Input.Simu.types_var=[1]; % Discrete values
Input.Simu.types_val=[1]; %Values as a set

The values that Zr will take during the study are defined as

Input.Simu.set_discvar={[22,24,26,28,30,32,34]};

Note for this kind of value you can also define the value as an interval with a linspace sampling with the correct min, max and number of point.

To look at the nominal vibration level, nominal sound power level and maximum sound power level one can specify

Input.Simu.names_resp={'Lvib'; 'LwrA';'LwrA_max';};

With the GUI, all these parameters are set in Workflow Sensitivity/ Optimization. First select "Sensitivity : All possible values" (it will test every single combination of the input, as we only have one input, it will create only 7 simulations). Then click on "Add Input" to set Zr:

370. Setup of a sensitivity input as a set of values with the GUI
Setup of a sensitivity input as a set of values with the GUI

Then click 3 times on "Add Output" and complete the new fields.

370. Setup of a rotor slot number sensitivity analysis with the GUI
Setup of a rotor slot number sensitivity analysis with the GUI

Note that you can edit input by clicking on its text and remove input or output by clicking on the corresponding red cross.

When varying the rotor slot number, the bar geometry and slot geometry are here unchanged and will affect the phase current. To study the slotting effects one can fix the current level using plot_MS_all_resp_var

Lvib = f(Zr)
Lvib = f(Zr)
LwrA = f(Zr)
LwrA = f(Zr)
Effect of the rotor bar number on the maximum sound level emitted by a variable-speed induction motor (MANATEE software output)
Effect of the rotor bar number on the maximum sound level emitted by a variable-speed induction motor (MANATEE software output)

7 different slot combinations have been here swept in a few seconds of calculation only. Results show that the choice of the rotor slot number has a large influence on the noise and vibration levels of induction motors. The best slot combination is here found with Zr=24. A complete study should involve the torque harmonics.

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