At the heart of our turbine sits a passive bearing system that offloads up to 90 % of the rotor's weight — eliminating the friction that kills small wind turbines before the breeze even starts.
The Root Challenge
Conventional small vertical-axis turbines use standard ball bearings to support the rotor's full weight. At the low wind speeds found on urban rooftops, bearing friction consumes a disproportionate share of available torque. The turbine stalls — or never starts at all.
Our engineers traced the problem to its root: offload the axial load and friction drops to near zero, letting the turbine respond to the gentlest breeze. The solution was hiding in physics — Ring magnets placed in mutual repulsion.
The Mechanism
Our rotor combines passive magnetic levitation, aerodynamic Savonius drag, and Darrieus lift — each force reinforcing the others so the turbine spins in almost any breeze and loses virtually no energy to friction.
Two ring magnets — one on the rotor, one on the fixed frame — face each other with the same magnetic pole. The repulsion force cushions the rotor axially without any mechanical contact.
The inner concave face of each carbon blade captures wind by drag, providing instant torque at even the lowest wind speeds. The turbine is fully self-starting — no electronics, no kickstart motor needed.
The outer leading edge forms a NACA-inspired airfoil. As wind flows across it, lift is generated — just like an aircraft wing. At higher speeds this effect takes over, dramatically boosting efficiency.
Earnshaw's theorem means purely passive levitation is unstable. A single ceramic ball bearing — carrying only ~10 % of rotor weight — provides radial control without reintroducing meaningful friction.
The three helix blades are moulded from aerospace-grade carbon fibre and finished in deep purple — maximising stiffness while minimising rotational mass, so the magnetic system has less work to do.
The entire assembly mounts directly onto standard chimney stacks at up to 1.2 m height — no permits, no new foundations — accessing cleaner airflow above rooftop turbulence.
Engineering Detail
Every element of the magnet pair has been chosen to balance holding force, stability and long-term reliability. The carbon fibre rotor keeps total rotational mass low — which means smaller magnets, lower cost, and a lighter stator structure.
The air gap between the rings is maintained at 2–4 mm. Within this range the repulsion force offloads the rotor while tolerating small manufacturing variations — critical for a product installed on a rooftop by a single technician.
On Earnshaw's theorem: purely passive magnetic levitation creates an unstable equilibrium. Our design acknowledges this — the magnets carry the weight, the mechanical bearing provides radial stability. Both together produce a system that is simultaneously near-frictionless and robust.
Real-World Performance
Small rooftop turbines are limited by swept area and available wind speed. Our design is honest about that — and optimised to extract every available watt from the conditions that actually exist on a Dutch rooftop, day and night, winter and summer.
Whether you are a housing corporation, researcher or municipality — we want to walk you through the full system. Let's build the next phase of the energy transition together.
Contact our team →