Examples

The examples live in bridge/python/examples. Run the bridge, connect the page and run the example (or let the example start the bridge itself).

Force sweep

forca_varredura.py builds a round conductor in a uniform 0.1 T field (imposed by the prescribed A on the border) and sweeps the current, comparing the Maxwell-tensor force with the analytical F = I·B·L:

mf = magfem.connect()
mf.run(MODEL)                       # geometry, materials, boundary and force table
for current in (10, 50, 100, 200):
    mf.set_var("I", str(current))
    mf.solve("n2")
    print(current, mf.result("Fx"), -current * 0.1)

Contactor

contator.py simulates the closing of a DC contactor (an axisymmetric plunger actuator), coupling in code three phenomena the app alone does not combine:

• electrical: λ ← λ + Δt·(V − R·i), with the current taken from the FEM λ(g, i);

• mechanical: m·g″ = F_spring(g) − F_mag(g, i), with the magnetic force from the Maxwell tensor on the plunger;

• geometry: at every step the air gap g changes, and the model is rebuilt, meshed and solved.

python examples/contator.py --key my-key --passos 60

The output shows t, g, i, λ and F and writes contator.csv. It reproduces the current dip typical of closing: as the plunger accelerates, the inductance grows and the current drops.

Ideas

• Optimization: feed mf.set_var and mf.result to scipy.optimize.minimize and optimize a dimension (air gap, magnet thickness) for an objective (force, inductance, losses).

• Maps: sweep two variables and build a λ(i, x) map for a circuit model.