Learning Forum

[Djuidje Rosine]

Hello everyone,

I want to model a stator coil using the finite element method, I need to calculate RLC parameters. I read in the ansys help, that it is possible to do this using the maxwell 2D model.
I used the electrostatic solver to calculate the capacity matrices.
firstly, i used the theory of electrostatics i excited each conductor separately by a voltage of 10 V. i obtained the same matrix in all cases. secondly, I excited all the conductors at the same time, I also obtained the same matrix. according to the theory, this is not true, when we excite the conductors with the same potential, the potential difference should be zero, and we would not be able to calculate the capacitance between two conductors.

i show you the design 2D.  it consists of 6 conductors surrounded by epoxy insulation as conductor insulation and epoxy as ground insulation. subsequently I put an air region and put a potential of 0V.
do I have to add a boundary condition for the calculation? 

i have done and the result of capacitance matrix .

Thanks you

[Deyu Li]

Hi, can you show where the excitations are? 

It looks like only 5 conductors in the middle, could you point out where is the 6th one? Could you also show where are copper, air and epoxy?

[Djuidje Rosine]

The copper conductors are those in white,
the epoxy is the one in green
and the tune is the one in yellow

 

[Deyu Li]

Exciting one conductor should give different field than exciting all conductors, which leads to different capacitance result.

Do you have ground (V=0V) assigned on any geometry? If yes, could you mark where is the V=0V place.

Do you have ground source checked as ground in Matrix?

[Djuidje Rosine]

 

the ground, I put it on the whole air zone (the whole region in yellow) because the coil is earthed via the last layer of the ground insulation.

 

[Deyu Li]

I made a similiar test, excitating each conductor separately and all conductors at the same time gave different results. It should be different, because the fields are not the same.

The capacitance equation could be found in Maxwell Manual, using keywords "compute a capacitance matrix".

[Djuidje Rosine]

the voltage 1  up to 6 are for the copper conductor and the voltage 7 is for the ground like this picture