Darrieus Engineering Notebook
Vertical-Axis Wind Turbine & Generator Research
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When does the rotor push harder than an electromagnetic winding short can resist?
Move the wind-speed slider. Compare rotor driving torque against hypothetical EM braking torque on the same generator-shaft RPM axis.
Exploratory model only. Direct three-phase AC terminal short · no diode bridge or battery · no stopping or safety prediction.
Explore the graph ↓The source rotor and Step 03 winding are read without changing your saved design.
Beaufort is a wind-speed label, not a physical braking threshold. Above 25 m/s the displayed rotor curves extrapolate the source Cp(TSR) scenario; this is not validated storm-wind data. Ghost curves show separate steady-state rotor scenarios, not a rotating machine speeding up over time. The dashed EM-braking curve is hypothetical.
HIGH-WIND EXTRAPOLATION · Above 25 m/s the source-derived rotor curve uses fixed-TSR wind scaling (RPM ∝ wind; torque ∝ wind²). Aerodynamics, survivability, RPM, currents and real braking are unverified. Not for safety or stopping decisions.
Awaiting selection and model…
Manufacturer RPM and current boundaries are screening references, not short-braking certification.
Solid coloured rotor curve above dashed amber means greater modelled driving torque at that generator RPM; dashed amber above the rotor curve means greater hypothetical braking torque. Where curves cross, the torques balance mathematically. No crossing means no crossing in the modelled and source-supported RPM envelope. None of this proves stability, startup or a complete stop.
Original v1.20.27 exploratory direct-short model: balanced Y phase approximation, sinusoidal open-circuit EMF proportional to generator RPM, winding copper loss and optional inductance. A manufacturer voltage/sag graph supplies a hypothetical resistance proxy, not measured winding resistance. The brake torque is not a calibrated TGET short-circuit measurement. No bridge, battery, controller, switching transients, saturation, thermal response, inertia, stopping time or static holding torque is simulated. A short-circuit should not be attempted based on this graph.
Any speed-reference or current-ceiling comparisons are indicative only. The short-duration current rating is not permission to short a winding for that time.