# Motor electromagnetic excitation force comparison in Maxwell 2D

Dear all,

Glad to join the community. I would be very grateful if someone can help me with this time.

I want to compare two motors' electromagnetic excitation (to evaluate motor's noise and vibration). I know we can compare the torque ripple and radial electromagnetic force(Please correct me if I am wrong).

But I don't know how to obtain the radial force in Maxwell 2D.

After some research in google, there may be three ways :

First one, force parameter way:select the stator and assign force in parameters before calculation. Then there will be a force_x and force_y in results. (But what's the meaning of this force? Can I use this force to obtain radial electromagnetic force? And how?)

Second one, maxwell stress tensor way: Define the formula in field calculator, then calculate the stator's radial force by integration along the stator's sideline.

Third one, edge force density way: select stator's sideline then assign edge force in field results. (What's the meaning of edge force density? How to use edge force density to compare two motor's electromagnetic excitation? What's the relationship of edge force density and parameter force? 

Cheers.

## Comments

?

As given by johnfides in another problem.

try this

for eddy current solution;

Quantity > B Loads the B vector

Function > Phase > OK

Complex > At Phase

Geometry > Line >

`edge of your material`

> OKUnit Vector > Normal

Dot

Quantity > H

Function > Phase > OK

Complex > At Phase

Multiply

Quantity > B

Function > Phase > OK

Complex > At Phase

Quantity > H

Function > Phase > OK

Complex > At Phase

Dot

Number > Scalar > 0.5 > OK

Multiply

Geometry > Line >

`edge of your material`

> OKUnit Vector > Normal

Multiply

Neg

Add

Scal? > ScalarX

Geometry > Line >

`edge of your material`

> OKIntegrate

Add…

@Supershun

In a rotating machine, if you want to study the net force on the rotor or stator you can simply select all the rotating elements and assign a force parameter this will give you the resultant force in x or y-direction. In a rotating machine, there are local forces acting all the time on stator tooth tips and on the rotor - responsible for vibration and noise. But due to a balanced winding and balanced rotor condition, the net force will be very less.

However, if you want to study the NVH aspects of the machine then you need to get the harmonic frequencies associated with these localized forces. Then you can create the arc elements around the stator tooth tips in the airgap.

Then, right-click on your design in the project manager window and select enable harmonic force calculation or go to maxwell 2d and follow the process below.

after you run the simulation you can couple this data directly for harmonic analysis in workbench and perform NVH analysis.