Home / Examples / Electric Analysis [Coulomb] / Example 17: Inductor's Floating Capacitance

Example 17: Inductor's Floating Capacitance

General

• The floating capacitance, or line-to-line capacitance, of a helical coil is solved.
   

• Unless specified in the list below, the default conditions will be applied.
   

• Obtain this session's project file. (Right-click and choose 'Save link as')




• Results will vary depending on Femtet version and the PC environment.

 

Analysis Space

Item	Settings
Analysis Space	3D
Model Unit	mm

 

Analysis Conditions

Item	Settings
Solver	Electric Analysis [Coulomb]
Analysis Type	Static Analysis (Capacitance)
Options	None

 

Set the Mesh Tab as follows.

Tab	Setting Item	Settings
Mesh	Meshing Setup	Automatically set the general mesh size: Deselect General Mesh Size: 2 [mm]

Graphical Objects

A helical solid body coil is defined.

Electric wall of 1 V is set on the whole of the coil body.

The ports are set on the edges of the coil where the floating capacitance is obtained.

Body Attributes and Materials

Body Number/Type	Body Attribute Name	Material Name
0/Solid	Coil	Coil
1/Solid	Air	* 000_Air

* Available from the material DB

 

Perfect conductor is set to the coil.

Material Name	Tab	Settings
Coil	Conductivity	Conductivity Type: Perfect Conductor

Boundary Condition

Set the electric wall of 1 V on the whole of the coil body.

The ports are set on the nodes where the floating capacitance is obtained.

Boundary Condition Name/Topology	Tab	Boundary Condition Type	Settings
1V/Face	Electric	Electric Wall	Electric Potential Specified 1 [V]
Port1/Face	Electric	Port
Port2/Face	Electric	Port
Outer Boundary Condition	Electric	Magnetic Wall

 

Results

To see the calculation results, go to the [Results] tab

 

 

 and click [Show Numerical Summary Table] .

 

 

C1-2 is the floating capacitance. It is about 0.5 [pF].