## Electronics

#### Maxwell/Electronics Expression Cache with Integration

• jdexter3
Subscriber

Hi, I am using ANSYS Electronics to calculate the radial force produced in the air gap for an SR machine. I have set an output variable for the radial force, it is a calculation integrated across an arc in the airgap using the radial and tangential flux densities.

When I go to the intrinsics tab in the expression cache, and attempt to define the integration over all points on the arc, the normalised distance only accepts a single value not a sweep. When trying to select all normalised distances I recieve an error saying it is not supported (using 18.2).

This is causing my results table to come out with zeros at every point, any ideas? Attached an image, please ask for more details if needed as I am new posting here.

• jdexter3
Subscriber

This is solved but I shall leave here for anyone interested. To solve this, do all calculations in the Fields Calculator, including the integration over a Geometry Line. Then simply recall the calculator expression into the expression cache with no further range or calculations required.

• n00nody
Subscriber

hi,jdexter3

can you tell me how to calculate the normal and tangent em force  on a toothtip of a pmsm motor?

I‘m a new learner for maxwell 2D?

thanks!!!

• jdexter3
Subscriber

Hi N00nody,

I strongly advise that you become familiar with the Fields Calculator in Ansys Maxwell, there are many tutorials for this.

There are multiple methods for calculating the forces acting on tooth tips, typically the Maxwell Stress Tensor forces are most commonly used. These can be defined as in:

http://docplayer.net/64276787-Electromagnetic-force-coupling-in-electric-machines-mark-solveson-cheta-rathod-mike-hebbes-gunjan-verma-tushar-sambharam-ansys-inc.html

This document also includes a piece of code you can note down to generate the forces on each node, at each time step. These must then be integrated against time across an arc of your definition, typically either the tooth tip edge or across an arc in the middle of the air gap spanning 1 pole pitch. I advise you do create a final variable after integration in the Fields Calculator, then assign the final variable to the expression cache, this is the fastest and most efficient way I found within Maxwell 2D.