Skip to content

Toroidal Winding Tutorial

Build a toroidal (ring) core magnetic component with windings.

Overview

Toroidal cores are fundamentally different from concentric cores (E, PQ, etc.):

  • The core is a ring that revolves around the Y axis
  • Turns are wound through the center hole
  • MAS coordinates use radial distance and angular position

Step 1: Load Test Data

import json

with open("tests/testData/T402416_edge40_4uH_8T.json") as f:
    mas_data = json.load(f)

Step 2: Generate the Complete Magnetic

from OpenMagneticsVirtualBuilder.builder import Builder

builder = Builder("CadQuery")

step_path, stl_path = builder.get_magnetic(
    mas_data,
    "T402416_4uH",
    output_path="./output/"
)

print(f"STEP: {step_path}")
print(f"STL:  {stl_path}")

Toroidal Core Geometry

A toroidal core requires only three dimensions:

Dimension Description
A Outer diameter
B Inner diameter
C Height (thickness) 
t_core_shape = {
    "name": "T 40/24/16",
    "family": "t",
    "familySubtype": "1",
    "dimensions": {
        "A": {"nominal": 0.0404},
        "B": {"nominal": 0.0246},
        "C": {"nominal": 0.0163},
    },
}

Toroidal Core Only

import copy

t_geo_desc = [
    {
        "type": "closed piece",
        "shape": copy.deepcopy(t_core_shape),
        "rotation": [0, 0, 0],
        "coordinates": [0, 0],
        "machining": None,
    }
]

step_path, stl_path = builder.get_core(
    "T_40_24_16",
    t_geo_desc,
    output_path="./output/"
)

Note

Toroidal cores use "type": "closed piece" since they are a single piece (unlike E-cores which use "half set").

Coordinate System

For toroidal cores, the coordinate mapping is:

Axis Direction
X Radial (negative X = inside the hole)
Y Core axis (toroid revolves around Y)
Z Tangential direction

MAS turn coordinates for toroidal cores:

  • coordinates[0] = radial distance from Y axis
  • coordinates[1] = angular position (rotation around Y axis)

Winding Styles

Toroidal windings pass through the center hole of the core. The CadQuery engine creates each turn as a torus swept along the winding path.

# Example turn in MAS format
turn = {
    "coordinates": [0.015, 0.2],  # radial, angular
    "winding": "Primary",
    "parallel": 0,
    "turnIndex": 0
}

Next Steps