Bobbins are made from dielectric materials that don’t interact directly with magnetic fields but are crucial for heat transfer and capacitance calculations. In TRAFOLO, bobbins are treated as a distinct geometry type. Users can create simple bobbin geometries using templates, and the Core, Coil, and Other geometry groups are automatically cut from the bobbin without generating overlap errors.
Bobbins can also be used to indicate regions for mesh refinement. We usually use it to refine mesh between windings, leading to more accurate results for leakage inductance and interwinding capacitance. Furthermore, even if air pockets exist between windings or the core in thermal simulations, users should fill these spaces with bobbins made of air. This approach allows the software to calculate heat conduction within the model rather than treating those regions as external boundaries.
Bobbin geometry groups
Geometry groups – Refer to complete or partial geometries that can be individually built from templates or imported as CAD. You can duplicate, delete, or rename these groups as needed. Individual groups can have different material properties assigned during the Assembly step.
Bobbin editor
TRAFOLO provides simple templates that imitate complex geometries but are sufficient for thermal analysis.
Default parametric template for generating bobbin and spacer geometries
Scale – The length dimensions must be set for imported geometries before importing the CAD model or creating the geometry. Once the geometry is created or imported, changing this value will have no effect, and you will need to re-import or re-build the geometry for the size setting to take effect.
IMPORTANT: After import, check the bounding box size in the preview window to ensure the geometry is correctly sized.
Geometry builder
Type
TRAFOLO provides parametric templates for the most commonly used geometry types:
- The Default template fills the space between core and winding.
- The Cylinder, Box, and other templates produce basic geometric primitives.
Linked Coil – This feature automatically retrieves coil parameters and uses them to construct and position the bobbin correctly.
Importing from CAD
Before importing your designs, refer to our LinkedIn article about fixing CAD geometries.
A single file is expected. When importing multiple geometries, those should be assigned to a single partition. Also, ensure that the imported geometries are non-overlapping.
To ensure the imported geometries have the correct dimensions, compare them with the bounding box in the preview window. It is essential to select the appropriate scale before initiating the import process. If, for any reason, the core is initially loaded with incorrect length dimensions, you can reset this by selecting the proper scale and repeating the import operation.
Importing bobbin geometry into TRAFOLO from external CAD software
Supported formats: *.step, *.stp, *.iges, and *.igs.
Geometry Handling Algorithm – Determines how the geometry, loaded from a CAD file, will be implemented into the Assembly:
- Unmodified – loads the geometry as it is and checks for any overlapping with other parts.
- Cut by Other Objects – cuts out any overlapping parts from the geometry. The priority of cutting is determined based on a hierarchy, with the winding being the highest priority, followed by the Core, Other, and the Bobbin.
Center by center of mass – linearly translates geometry to its center of mass. After closing this window, you can translate geometry by coordinates.
Fuse Bodies – Merges imported geometries into a single body. This option can help address certain geometrical issues before Assembling.