The guide is showing a prepared demonstration run. Your own run and traces are kept unchanged; choose Explore from here to continue from the demonstration.
Experiments Change the actual model
Manual rotor position
Interlock: release the shaft lock to position the rotor by hand. The lock is an ideal constraint on the shaft.
Reset experiment Run physics checks
Manual positioning pauses the run and de-energizes the drive. Disabling phase A turns off its gates, not its body diodes.
Stationary, energized motor with default drive settings; releases lock and fault, clears traces and starts a new run.
Physics checks Tests run on isolated model instances and do not change your experiment.
These consistency tests check the implementation. They do not certify the model against a manufactured motor or a nonlinear electromagnetic solver.
Click a component in the model to inspect it.
Model, equations and limits Geometry and wiring An inner permanent-magnet rotor has four radially magnetized arc magnets: N–S–N–S at the air gap. Six insulated stator teeth carry concentrated copper windings, 36 rendered turns per tooth. Opposite teeth form two series coils per phase, and the three returns meet at one floating star point. A1/B1/C1 occupy 0°/60°/120° mechanical; A2/B2/C2 occupy 180°/240°/300°. Three Hall sensors at 30°/90°/150° mechanical give 120° electrical spacing.
Electrical drive The Hall code selects a high-side PWM leg, a low-side return leg, and an undriven leg. Kirchhoff's laws determine winding currents and the floating star voltage. Inductance is not discarded at commutation: undriven current continues through the appropriate body diode until it reaches zero. Brake shorts all phases through the low-side switches.
Magnetic field A conservative 193 × 193 finite-volume discretization solves the active-stack magnetic vector potential. The embedded basis includes three winding-current fields and five odd spatial harmonics of the rotating remanence. Each phase flux linkage is extracted with the same winding functional that excites the field; its derivative supplies both back EMF and torque, which preserves Σe·i = τ·ω. Contours trace B, and the field does not disappear when power is removed.
v − v_Y = R i + L di/dt + e i_A + i_B + i_C = 0 e_k = ω ∂λ_PM,k / ∂θ τ_e = Σ i_k ∂λ_PM,k / ∂θ J dω/dt = τ_e − τ_load − bω − τ_friction
Read the overlays correctly Red = north; blue = south. Rotor labels refer to each magnet's outward-facing pole; its concealed inner face has the opposite pole. Stator pole tint follows the total field normal to the air-gap face, so even an unpowered tooth can be polarized by the rotor.
Amber / mint / violet = phases A / B / C. Moving arrowheads show conventional current, not electron flow. Their travel speed is illustrative; their direction and visibility follow the solved signed current. ⊙ is current toward you, ⊗ is current away.
The magnetic field is a 2D mid-stack solution lifted forward in the 3D view so that its return paths through iron remain visible. It is not a three-dimensional end-fringing solution. Contour spacing represents equal flux per unit axial length within each snapshot; the contour scale is adjusted for readability.
Scope and limitations This is a physically coupled educational reference, not validated motor-design software. Steel uses fixed μr = 600; saturation, hysteresis, eddy-current loss, temperature, magnet demagnetization, saliency/cogging torque, and end leakage are omitted. A finite outer boundary and Cartesian discretization introduce field errors, and the annular permeability model smooths the narrow gaps between magnets.
PWM is voltage-averaged with current-dependent duty foldback near 6 A. Switching ripple, dead time, MOSFET losses, and parasitic wiring inductance are not resolved. Body diodes are ideal. The DC bus is a stiff bidirectional source that absorbs regenerated energy. Field-map tesla values are model estimates, not measurements.
X-ray and exploded views change presentation only. Slow motion advances every physical variable on the same scaled clock. Shaft speed readouts always report physical rpm.
Primary technical references: semiconductor manufacturers’ application notes on trapezoidal control of BLDC motors with Hall-effect sensors and on six-step sensored commutation; finite-element magnetics references for the permanent-magnet source formulation and boundary conditions.
Linear 2D magnetostatics coupled to circuit and rotor dynamics. A reference machine for teaching, not a manufacturer's digital twin.
